"ADHD" Stimulants

ADHD Pentacle

This mini-booklet reviews the relative effectiveness, safety and harms of psychiatric drugs that are prescribed to people diagnosed with Attention Deficit/Hyperactivity Disorder.

How is the information about psychiatric drugs on this page different from what’s provided by other online resources, and why should I read it?

Inner Compass Initiative has developed these informational pages because many descriptions of the safety and effectiveness of psychiatric drugs that are provided by popular online medical, psychiatric and mental health websites are often brief, vague, and more promotional than factual. (For an examination of some of the reasons why this is the case, please read ICI’s “How Psychiatric Drugs are Researched and Marketed”.) We believe that, when trying to make serious, potentially life-changing decisions about whether to take or discontinue psychiatric drugs, people deserve a fairer opportunity to properly understand and evaluate the potential risks and benefits, and thereby be empowered to make informed choices. Our articles will take you more time to read because they provide more detailed information than most of the overviews you’ll read elsewhere – but isn’t your health worth the investment?

If you notice an error, broken link or needed update, please contact us. Click here to learn more about Inner Compass Initiative.

Why do Inner Compass Initiative’s reviews of safety and effectiveness focus mainly on the FDA-approved drug labels?

Inner Compass Initiative’s mini-booklets about the six main classes of psychiatric drugs do not review all of the scientific research about these drugs. That would be an extremely ambitious effort that could easily fill an entire book for each drug class, after which even the most neutral team of researchers could still be accused of “cherry picking” evidence from tens of thousands of available studies. We have taken a different approach. We’ve focused mainly on reporting and clarifying what is arguably the single most important body of evidence: The evidence that drug companies themselves provided to government health regulators in order to try to establish evidence that their drugs are safe and effective.

If a pharmaceutical company wishes to market a prescription drug for a specific use in the United States, the company is legally required to provide scientific evidence in support of its application to the Food and Drug Administration (FDA). If the drug is approved by the FDA, this evidence is then summarized in the official “drug label”. The information pamphlets for consumers that come with prescription drugs are often unregulated, general information about the drug or just a brief collection of highlights from the drug label. In its complete form, the official drug label can be ten to fifty pages or longer in length, and includes the “Full Prescribing Information” and “Medication Guide” that are intended to inform physicians, psychiatrists, pharmacists and others about the most important scientific evidence relating to the safety and effectiveness of that drug. Since the drug labels are generally based on evidence provided to the FDA by the drug companies themselves, and are developed in collaboration between the drug companies and FDA, they tend to be strongly biased in favor of the drugs. Yet even with this bias, we at Inner Compass Initiative believe that most readers, like us, will find much of the information in them to be enlightening, surprising, concerning and even at times shocking – and nothing if not helpful for making more informed decisions weighing the potential risks and benefits of psychiatric drugs. So in creating our mini-booklets, we distilled the contents of a representative sampling of drug labels from each major class of psychiatric drugs -- supplemented at times with information from related scientific studies and the FDA's own medical reviews. (Also included are some general Q&As about key ideas in psychiatric science such as safety, effectiveness, and drug dependence, which apply to essentially all psychiatric drugs and are duplicated across the mini-booklets.)

Still, we urge anyone who is considering or already taking any psychiatric drug to read the official drug label in full. These are freely available online at a variety of commercial websites, but the most reliably up-to-date sources are those run by the federal government such as DailyMed. (Instructions and links for obtaining and understanding drug labels and related information such as FDA medical reviews can be found in our “Guide to the FDA-approved Drug Labels”.) We also strongly recommend doing additional self-directed research, such as examining the FDA’s internal medical reviews, using online tools for searching scientific journal articles, perusing Inner Compass Initiative’s “Resources” section, conferring with people who’ve taken the drug, and consulting with well-informed, supportive prescribers or pharmacists. Choice is only truly meaningful – and truly possible – when it is informed.

What are ADHD drugs and what are they prescribed for?

“Attention Deficit/Hyperactivity Disorder” (ADHD) is a diagnostic label that is typically applied to people who seem to have difficulty maintaining attention and focus on tasks that others expect them to complete, such as schoolwork or job responsibilities, and who seem to act with shifting, unfocused energies that others may find disruptive.

The drugs that are most commonly prescribed to people who’ve been given the diagnostic label of ADHD are central nervous system stimulants. Generic names for these drugs include amphetamine, dextroamphetamine and lisdexamphetamine (e.g. U.S. brand names Dexedrine, Adderall, and Vyvanse) and methylphenidates (e.g. Ritalin, Concerta and Daytrana). A few, like atomoxetine (Strattera) and guanfacine (Intuniv), are not strictly considered to be stimulants, but have similar chemical effects.

Some physicians also prescribe antipsychotic and antidepressant drugs to people who’ve been given the diagnostic label of ADHD, even though this use is “off-label”. (When a physician prescribes a drug for a use that has not been approved by the U.S. Food and Drug Administration and is not listed on the official drug label, the physician is prescribing “off-label”.) Please read ICI’s “Antipsychotics” or “Antidepressants” for information on those classes of drugs.

How do ADHD drugs work?

Notably, the answer to the above question is, in some important ways, similar for all of the major classes of psychiatric drugs: We don't truly know. It can be misleading to talk about how ADHD drugs work, because the word “work” implies that the drugs have a well-understood effect on a discrete area or pathway in the brain that’s involved in attention and focus, or cure an abnormal biological condition, disease or disorder. For many it can be surprising to hear because we’re so often led to believe otherwise, but there is still today no known, biologically detectable mental disorder or discrete area or pathway in the brain that drugs that are prescribed for people diagnosed with ADHD treat or cure. (For more information, read ICI’s “How Mental Disorders are Diagnosed” and “How Psychiatric Drugs are Researched and Marketed”.)

ADHD drugs are psychoactive chemicals that act on the brain in a variety of ways. It is common for popular medical websites, news media, non-profit organizations, and even many medical and mental health professionals to make claims that ADHD drugs re-adjust a biochemical imbalance, compensate for brain structure abnormalities, “help nerves in the brain talk to one another” or “make the pathways in the brain work more effectively”.

These kinds of characterizations resemble promotional advertisements for these drugs more than factual statements. Indeed, the U.S. Food and Drug Administration (FDA) and pharmaceutical manufacturers have developed medically definitive descriptions of the mechanisms of action for every ADHD drug that is approved for use in the United States. These can normally be found in the “Clinical Pharmacology” section of the official drug label. (Instructions and links for obtaining and understanding drug labels can be found in our “Guide to the FDA-approved Drug Labels”.) According to these explanations, the biological mechanisms by which any ADHD drugs might affect some people diagnosed with mental disorders in “therapeutic” ways are “unknown”. For example, the drug label for Ritalin clarifies that, “There is neither specific evidence which clearly establishes the mechanism whereby Ritalin produces its mental and behavioral effects in children, nor conclusive evidence regarding how these effects relate to the condition of the central nervous system.”

It is known that, in part, all of the ADHD drugs disrupt and alter the activities of important neurotransmitters in a myriad of complex ways – ways that also tend to change over time as the body reacts to the presence of the drugs. Neurotransmitters are key chemical messengers that are vital for communication between nerve cells and in the effective functioning of our brain, nervous system, and body. ADHD drugs work by disrupting or altering the functioning of many neurotransmitters including epinephrine (adrenaline), norepinephrine, dopamine and serotonin. These neurotransmitters are variously involved in emotions and moods, sensory and reward perceptions, sleep, appetite, motor system functions, motivation, pleasure, wakefulness, attention, sexual arousal, memory, cognition and much more, in ways that no one fully understands. This is why ADHD drugs can produce such a wide range of effects, both wanted and unwanted.

Many users report that ADHD drugs tend to create for them an apparent short-term increase in energy, alertness, attention and focus. These are effects that are commonly reported by people who take stimulant drugs whether they have an ADHD diagnosis or not. In other words, it is likely that these drugs “work” through some of the commonly recognized effects of any stimulant drug.

Are ADHD drugs effective? – But first, what does “effective” mean?

We often hear that certain psychiatric drugs are effective. But it’s rarely explained what exactly “effective” means. Does effective mean that the drug makes everyone feel completely better? Or if some people feel better when taking the drug, in what ways do they typically feel better, by how much, and for how long a time? And do some people feel worse in certain ways because of the drug?

Unless you ask probing questions, or carefully and critically analyze scientific studies yourself, it’s difficult to know exactly what certain people mean when they state that a particular psychiatric drug is effective. Often, different people can even look at the same scientific evidence and reach opposite conclusions about whether a psychiatric drug demonstrated true effectiveness or not. (For more information, please read ICI’s “How Outcomes are Measured in Psychiatric Research” and “How Psychiatric Drugs are Researched and Marketed”.) Yet when deciding if a drug is right for you or for someone you care about, it is very important to have a strong understanding of in what ways the drug is apparently effective and to what degree it is apparently effective, so that you can reasonably weigh the potential benefits of the drug against its potential adverse effects.

As we described in our introductory section, one helpful way to resolve these challenges and learn about a psychiatric drug’s effectiveness is to examine the actual medical evidence that resulted in the FDA approving the drug to legally be described by the pharmaceutical manufacturer as “effective” for the drug’s intended use. This evidence comes from the clinical trials that a pharmaceutical company presented to the FDA in order to try to establish their drug’s effectiveness. Though these trials were sponsored and selected by the drug companies and so tended to be biased in favor of the drugs, they are still extremely instructive. So in this article, we provide some representative examples of how drug companies tried to prove to the FDA that their drugs were effective – and we examine what “effective” actually meant in that context.

How effective are ADHD drugs and in what ways are they effective?

According to the evidence provided to the FDA, all of the ADHD drugs are effective over periods of about 1 to 8 weeks at slightly reducing the frequency or intensity of some of the behaviors associated with the diagnostic label of Attention Deficit/Hyperactivity Disorder.

As a representative example, the drug Concerta (methylphenidate) was approved by the FDA in 2000 as effective in the treatment of childhood ADHD on the basis of three clinical trials. In two of these trials, children were prescribed Concerta, Ritalin or placebo pills for just one week, and in one trial children were prescribed Concerta, Ritalin or placebo for four weeks. The children’s behaviors were then scored by teachers who were asked questions like whether the children seemed to be never, sometimes, often or very often fidgety, excitable, or easily distracted. (For more information, see ICI’s “How Outcomes are Measured in Psychiatric Research”.) On a scale of 15 total points, the teachers rated the behaviors of the children taking either Concerta or Ritalin on average about 3-5 points lower (or “less inattentive/disruptive”) than the children taking placebo pills.

The FDA’s analysis of these Concerta trials revealed some of the ways in which these findings were even weaker than they appeared:

  • The selection of trial participants was biased in favor of the drug, because all of the children who participated had been identified before the trials began as good responders to methylphenidate drugs. In addition, any children known to not respond well to methylphenidates were excluded from participating.
  • All of the children in the trials had already been taking methylphenidate drugs for some time; consequently, the children who were put into the placebo groups were forced to suddenly stop taking their drugs. Since methylphenidates can cause physical dependence to develop, many of the children in the placebo group were likely experiencing acute drug withdrawal during these trials, which likely would have destabilized them and affected their levels of attention and hyperactivity. (See below for further discussion of dependence on ADHD stimulants and withdrawal.)
  • Compared to the children taking placebo pills, the children continuing to take the drugs still experienced many times more adverse physical and psychological effects, such as abdominal pains, coughing, sinus problems, dizziness, twitching, insomnia, hostility, depression, and anorexia. The increases in these adverse effects, though, were not relevant to the measuring of the effectiveness of Concerta at reducing specific disruptive and inattentive behaviors associated with a diagnoses of ADHD.
  • All of the children in the trials that were taking either drugs or placebo pills generally achieved lower (or “improved”) scores. And during the longer, four-week trial, the children taking placebo pills kept steadily improving week by week while the children taking drugs did not.
  • There was no evidence that the children taking the drugs were improving in other aspects of their lives such as academic achievement, social relationships, or levels of happiness, since the studies focused only on whether ADHD-related behaviors changed.

Nevertheless, the results of these clinical trials were enough for the FDA to allow the pharmaceutical company to state that Concerta is effective in treating pediatric ADHD.

These findings are a fair representation of the general level of effectiveness of ADHD drugs. As another example, in 2002, the ADHD drug Strattera was approved by the FDA as similarly effective to Ritalin in the treatment of children diagnosed with ADHD on the basis of four trials lasting only eight weeks. On a 54-point scale rating inattentive and disruptive behaviors, parents scored the children taking the drug on average only about 8-10 points lower than the children taking placebo.

In 2015, a large international team of medical scientists in the Cochrane Collaboration reviewed 185 clinical trials of ADHD methylphenidate drugs conducted over several decades. Most of the clinical trials, they wrote, were small, short in duration, and scientifically “of low quality” as they tended to have high risks of bias in favor of the drugs. Yet even then the researchers noted that, overall, the studies showed that children’s improvements on the drugs barely passed the absolutely minimal level necessary for being considered to be clinically relevant or meaningful. And these findings were “very low-quality evidence”, they wrote, because they were based only on teachers’ ratings. Because the drugs were also clearly causing a variety of adverse side effects, the authors could not conclude that taking stimulants would improve the lives of children and adolescents who’d been diagnosed with ADHD, even over the short term.

These limited levels of effectiveness of ADHD drugs are important to understand when trying to appropriately weigh their potential benefits against their potential harms.


Related reading:

U.S. Food and Drug Administration. Concerta Drug Approval Package: Medical Review. (2000)

U.S. Food and Drug Administration. Strattera Drug Approval Package: Medical Review (Part 2). (2002).

Storebø, Ole Jakob, Erica Ramstad, Helle B. Krogh, Trine Danvad Nilausen, Maria Skoog, Mathilde Holmskov, Susanne Rosendal, et al. “Methylphenidate for Children and Adolescents with Attention Deficit Hyperactivity Disorder (ADHD).” In Cochrane Database of Systematic Reviews. John Wiley & Sons, Ltd, 2015.

How effective are ADHD drugs over long-term use?

Many children and adults who take ADHD drugs take them not for weeks or months, but for many years. Yet the FDA has not evaluated the long-term effectiveness of any ADHD drugs, and there have been almost no published medical studies examining the long-term effectiveness of ADHD drugs compared to non-drug interventions or placebo pills.

The Multimodal Treatment Study of Children with ADHD (MTA) began in the 1990s and was the U.S. National Institute of Mental Health’s major attempt to respond to the fact that, as the authors wrote, “long-term efficacy of stimulant medication has not been demonstrated for any domain of child functioning”. This study found that, after 14 months, children taking stimulant drugs achieved slightly lower (or “better”) scores for ADHD-related behaviors. However, after three years, the authors found that “medication use was a significant marker not of beneficial outcome, but of deterioration”. After six years, the MTA study reported that stimulant use was “associated with worse hyperactivity-impulsivity and oppositional defiant disorder symptoms” and with “overall functional impairment”.

The National Institute of Mental Health has stated that there are limitations to what can be interpreted from these findings beyond 14 months, partly because the children who had worse problems might have been more likely to continue taking drugs. In any case, the MTA failed to find that long-term stimulant use was effective for helping people diagnosed with ADHD.

Less formally-structured investigative reports produced by the government of Western Australia and the Bureau of Economic Research in Quebec, Canada also found that long-term stimulant use did not seem to improve outcomes for children diagnosed with ADHD when compared to children who were also diagnosed with ADHD but did not take drugs, or who took drugs only for a brief period. The Western Australia study found that children taking drugs continuously for about 8 years had higher blood pressure and were more likely to have academic problems. The Canadian study also found an association between long-term medicating and academic failure, as well as a greater likelihood of mood problems.


Related reading:

Richters, J. E., L. E. Arnold, P. S. Jensen, H. Abikoff, C. K. Conners, L. L. Greenhill, L. Hechtman, S. P. Hinshaw, W. E. Pelham, and J. M. Swanson. “NIMH Collaborative Multisite Multimodal Treatment Study of Children with ADHD: I. Background and Rationale.” Journal of the American Academy of Child and Adolescent Psychiatry 34, no. 8 (August 1995): 987–1000. doi:10.1097/00004583-199508000-00008.

Jensen, Peter S., L. Eugene Arnold, James M. Swanson, Benedetto Vitiello, Howard B. Abikoff, Laurence L. Greenhill, Lily Hechtman, et al. “3-Year Follow-up of the NIMH MTA Study.” Journal of the American Academy of Child and Adolescent Psychiatry 46, no. 8 (August 2007): 989–1002. doi:10.1097/CHI.0b013e3180686d48.

Molina, Brooke S. G., Stephen P. Hinshaw, James M. Swanson, L. Eugene Arnold, Benedetto Vitiello, Peter S. Jensen, Jeffery N. Epstein, et al. “The MTA at 8 Years: Prospective Follow-up of Children Treated for Combined-Type ADHD in a Multisite Study.” Journal of the American Academy of Child and Adolescent Psychiatry 48, no. 5 (May 2009): 484–500. doi:10.1097/CHI.0b013e31819c23d0.

Smith, Grant, Brad Jongeling et al. “Raine ADHD Study: Long-term outcomes associated with stimulant medication in the treatment of ADHD in children.” Government of Western Australia Department of Health. (February, 2010).

Currie, Janet, Mark Stabile and Lauren E. Jones. “Do Stimulant Medications Improve Educational and Behavioral Outcomes for Children with ADHD?” The National Bureau of Economic Research. (June, 2013).

Stratton, Allegra. "Ritalin of no long-term benefit, study finds." The Guardian. (November 12 , 2007.)

If ADHD drugs are not very effective, why do I/do some people seem to become much better when taking them?

If you read all of ICI’s mini-booklets on the major psychiatric drug classes you will notice that, based on the clinical trial information that was provided to the FDA, most psychiatric drugs seem to have at best very modest, short-term effectiveness in helping people diagnosed with mental disorders. These findings generally match the findings in the broader scientific literature as well. Yet some people report that they benefit immensely from taking certain psychiatric drugs. What is going on?

Many psychiatric drug trials do show that a percentage of people respond much more positively than most other people to certain psychiatric drugs. However, the studies generally cannot shed light on why that’s happening. Are these random, “lucky” occurrences? Is there a particular subgroup of people who respond better to certain psychiatric drugs due to unknown genetic, biochemical or lifestyle differences? Do a person’s responses tend to be greater or smaller depending on what is actually causing the person’s problems?

One important factor has been extensively studied: Psychiatric drug trials tend to have the highest placebo response rates in all of medicine. Most psychiatric drug trials show the majority of participants scoring substantially better on improvement tests whether they are taking a drug or placebo – apparently, simply hoping or believing that they are taking a potentially helpful psychiatric drug seems to be very helpful for many people. Indeed, in most trials this placebo effect accounts for a much larger portion of people’s apparent improvements than the drugs themselves. So while we can determine scientifically that the overall positive effects of a particular psychiatric drug are relatively modest, some people will experience the effect of the drug plus a very substantial placebo effect, which can make the drug seem to be much more effective than it otherwise might to those people personally.

There can also be, for example, “social placebo” effects, where having the encouragement and support of mental health professionals, family, and other people around you when you take a psychiatric drug can change both their and your feelings and behaviors in ways that can contribute significantly to the positive overall impacts of a drug. In addition, after experiencing some initial benefits from a drug, over time some people can have a tendency to attribute further positive developments in their moods and experiences to the drug while attributing negative developments to re-emergence of their own underlying problems.

Alternatively – and some experts argue most importantly – some people might simply more strongly like or have positive therapeutic responses to the sedating, numbing or stimulating effects of certain prescribed psychiatric drugs on their feelings, experiences or behaviors, in similar ways to how some people respond positively to the effects of coffee, cigarettes, painkilling medication, alcohol, marijuana or other drugs.

If ADHD drugs are not very effective, why do I/do some people seem to become much worse when stopping them?

Many people find that, when they stop taking psychiatric drugs after long periods of regular use, they rapidly start to feel worse. They may then believe (or they may have been told by their prescriber or others) that this is because the underlying problem that the drug was treating has re-emerged. This could be the case; however, there is actually a more likely explanation.

All psychiatric drugs are, to greater or lesser degrees, dependence-forming – today, the majority of drug labels for all classes of psychiatric medications include indications of this fact. Benzodiazepines, stimulants, and Z-drugs are specifically classified as Controlled Substances in the United States due to their potential for causing dependence and addiction. And the drug labels for most antidepressants and anticonvulsant “mood stabilizer” drugs, along with many antipsychotics, include specific cautions about “drug discontinuation syndromes” (withdrawal symptoms) that have been observed.

Essentially, “dependence-forming” means that, over time, the human body adjusts to the presence of these drugs in biochemical and structural ways. When stopping the drugs suddenly, many people will experience very uncomfortable or even dangerous physical and mental withdrawal symptoms, as the body is forced to rapidly re-adjust to the absence of the drugs.

Among many other possible withdrawal symptoms, abrupt discontinuation of psychiatric drugs commonly produces unusually extreme and intense manifestations of some of the feelings, experiences or behaviors that the drugs were helping to suppress. For example, stopping a sedating drug is likely to cause withdrawal symptoms such as abnormally intense anxiety and agitation. Stopping a numbing drug is likely to cause withdrawal symptoms such as hypersensitivity and moodiness. Stopping a stimulant drug is likely to lead to feelings of unusually intense depression. Moreover, some withdrawal symptoms can continue for weeks, months, or even years until the body and brain have had enough time to fully re-adjust to the absence of the drug. (For more information, see The Withdrawal Project’s overview essay, “Psychiatric Drug Tolerance, Dependence and Withdrawal”.)

Are prescription stimulants like ADHD drugs similar to cocaine and “street meth”, and is it true that these drugs affect people diagnosed with ADHD differently than they affect other people?

Central nervous system stimulant drugs that are commonly prescribed for ADHD are chemically similar to recreational stimulants like amphetamines, cocaine and street “meth”, and as a result have similar physical and psychological effects. Some of the stimulants prescribed to people diagnosed with ADHD are in fact amphetamines (e.g. Adderall) or methamphetamines (e.g. Desoxyn). This is why many common ADHD drugs have become popular recreational drugs as well.

There is no scientific evidence to support the claim that prescription and recreational stimulants affect “normal” people differently than they affect people diagnosed with ADHD. The main difference is that recreational stimulant use typically involves higher doses or more rapid consumption methods (such as “snorting” powder through the nose, which takes a drug more directly into the bloodstream). At comparable dosage levels, the main effects of both prescribed and recreational stimulants tend to be similar in both groups. For example, the U.S. National Institute on Drug Abuse explains that, in most humans, ADHD drugs and drugs like cocaine and methamphetamine tend to temporarily “increase focus and attention”.

How safe or dangerous are ADHD drugs? Do I really need to read about and concern myself with all of those apparently minor or rare adverse effects?

It’s often claimed that psychiatric drugs are safe. But what does “safe” actually mean? Different people can mean different things when they say that a drug is generally safe.

The FDA requires pharmaceutical companies to conduct some basic studies into the safety of their drugs. The findings from these studies are then included in the official FDA-approved drug labels under the assumption that patients and prescribers will then together review and weigh a drug’s potential risks and benefits. All prescribing physicians, psychiatrists and pharmacists are ethically and legally required to ensure that patients are informed about the potential harms of any drug that is being prescribed to them. In practice, though, this rarely occurs with respect to any drugs let alone psychiatric drugs, and patients often receive information which is incomplete or inaccurate. 

Prescribers themselves are not always fully informed. The lists of potential adverse effects for most psychiatric drugs are lengthy, and many prescribers are too busy to either learn about them all or, if they do learn them, convey them all to patients. Some prescribers don’t want to dissuade or frighten people from taking psychiatric drugs that they are recommending. Even the more responsible prescribers often just direct patients to read unregulated information or brief highlights of the drug labels that may accompany packages of prescription drugs. Relatively few of us ever read even these inserts, though, and instead we simply trust general reassurances from prescribers. This attitude is usually founded on a basic, deep trust of the medical profession, drug regulators, and scientific research. To learn more about why this trust should be balanced with healthy skepticism, please read ICI’s “How Psychiatric Drugs are Researched and Marketed”.

As we discussed in our introduction, even though the risk and safety information included in the drug labels tends to be biased in favor of the drugs, these labels can still be very informative. That said, it’s easy to feel like it’s not worth the effort to read about all of the adverse effects identified in these lengthy drug labels, because many of them can seem relatively trivial, while many of the more serious side effects are identified as being rare. However, there are other important factors to take into consideration:

  • The real adverse effect rates are unknown and often higher. Most of the adverse effects that are listed in the FDA-approved drug labels are the ones that appeared in relatively short clinical trials involving small numbers of people – so the actual adverse effects in typical users are unknown, and reasonably likely to be (and are often later found to be) much larger in number and varied in type. Indeed, sometimes the drug labels include reports of many more adverse effects in a section called “Post-marketing Experience” – these are lists of adverse effects that started being identified and voluntarily reported to the FDA after many more people in the general population began regularly using the drugs. Because these reports are voluntary, though, the absence of such reports cannot be taken as evidence of a drug’s safety.
  • "Infrequent" doesn’t always mean unlikely. It’s true that any particular, individual user is relatively unlikely to experience any one particular, infrequent adverse effect. However, taken all together, in most cases it’s very likely that most users will experience at least some of the listed adverse effects.
  • "Rare" can add up to a lot of people. In the drug labels, some potentially very serious adverse effects may be described as “rare”. This refers to the fact that small numbers of people will experience a particular adverse effect relative to the overall number of people taking the drug. However, it’s important to remember that, with millions of Americans taking certain psychiatric drugs, “rare” can easily mean that thousands or ten of thousands of Americans will be experiencing that very serious adverse effect.
  • Minor adverse effects may be warning signs. Apparently minor adverse effects can sometimes be early warning signs for more serious, rarer adverse effects; therefore, knowing the minor adverse effects could help prevent more serious harms or even, sometimes, save your life. 
  • Adverse effects reveal a lot about how a drug works. Understanding the full range of possible adverse effects helps you better understand the ways in which a drug is acting on your body and brain.
  • Your choice is better informed. Understanding the adverse effects helps you make a more informed choice about whether, for you, the relative effectiveness of a drug truly outweighs the potential harms.

Deciding to take a psychiatric drug or encouraging a friend or loved one to take a psychiatric drug, especially when it could potentially be for a long time, is a significant choice that could change the course of your or someone else’s life. The only way to make a truly, meaningfully informed choice is to try to ensure that you get the best information and advice that you can to help you think through the decision. If you or someone close to you is taking or considering taking any psychiatric drug, we encourage you to make the time to read the entire drug label. In this article, we have reviewed only a small sampling of the adverse effects identified in these labels, so below we also include links to several places where the U.S. FDA-approved drug labels can be viewed freely in full. However, in light of the limitations of this information, it’s even better to supplement it by examining the FDA’s “drug approval packages” (which include internal medical reviews of a drug), doing wider research, and consulting with well-informed, supportive practitioners.

At the same time, for anyone taking any psychiatric drug, the complexity of all of this information is an important reminder of the vital importance of always trying to listen closely to the wisdom in what your own body is telling you.


Related reading:

Instructions and links for obtaining and understanding drug labels can be found in The Withdrawal Project's “Guide to the FDA-approved Drug Labels”.

U.S. Food and Drug Administration. Drugs@FDA: FDA Approved Drug Products.

U.S. Food and Drug Administration. Drugs@FDA Instructions: Health Information. (A quick guide to searching the FDA’s drug information system.)

U.S. National Library of Medicine. DailyMed

What are the immediate and most common adverse effects of ADHD drugs?

Some of the most common, immediate adverse effects of ADHD drugs include accelerated heart rate, headache, high blood pressure, loss of appetite, nervousness, anxiety, insomnia, and mood swings. Some of these effects are discussed in more detail below.

How severely do ADHD drugs worsen sleep?

According to their drug labels and many studies, all ADHD drugs generally cause people to have two to five times higher rates of insomnia. In surveys covering relatively short periods of time, about 25% of users of ADHD drugs reported experiencing insomnia.

How severely do ADHD drugs affect appetite?

According to their drug labels and many studies, ADHD drugs generally cause people to have two to five times higher rates of loss of appetite and loss of weight. In surveys covering relatively short periods, about 25% of people who were taking an ADHD drug experienced decreased appetite, and for 2% it was severe enough to be identified as anorexic.

This significant interference by the drugs in basic metabolic processes is poorly understood. Some emerging evidence has actually linked ADHD drugs to weight gain over long-term use or after termination of long-term use, especially in adults.


Related Reading:

Schwartz, Brian S., Lisa Bailey-Davis, Karen Bandeen-Roche, Jonathan Pollak, Annemarie G. Hirsch, Claudia Nau, Ann Y. Liu, and Thomas A. Glass. “Attention Deficit Disorder, Stimulant Use, and Childhood Body Mass Index Trajectory.” Pediatrics, March 1, 2014, peds.2013-3427. doi:10.1542/peds.2013-3427.

How severely do ADHD drugs stunt growth?

According to their drug labels and many studies, all ADHD drugs slow physical growth and development in children. Over three years, children aged 7-13 taking ADHD drugs typically grow about 1 inch (2 cm) less and 6 pounds (2.7 kg) less. Little is known about other possible, long-term consequences on the brain or body of this interruption of normal growth during crucial years of child and adolescent development.

How often do ADHD drugs cause verbal and motor dysfunction or tics?

Many ADHD drugs have the capacity to cause the onset or worsening of motor and verbal dysfunction in some children. These abnormal movements are called tics. They can take the form of repetitive movements or utterances, or intermittent, irregular, abrupt shaking of particular parts of the body. If there are several complex tics, then it is usually referred to as Gilles de la Tourette syndrome, or Tourette’s syndrome for short. Many ADHD drugs are not recommended for use by people who already experience tics. According to various ADHD drug labels, after two years, about 1-9% of children taking stimulant drugs will develop tics. These tics are not necessarily permanent.

Can ADHD drugs cause depressed or manic feelings or psychosis-like experiences, or even possibly lead to a diagnosis of Major Depressive Disorder, Bipolar Disorder or Schizophrenia?

ADHD drugs disrupt or alter the functioning of at least four major neurotransmitters in the brain in ways that are not fully understood, and so the drugs can have unpredictable effects on the mind. According to their drug labels, some of the identified mental side effects of many ADHD drugs, especially over long-term use, include anxiety, irritability, agitation, panic attacks, mood swings, aggression, hostility, violent behaviors, impulsivity, and depressed mood.

In addition, ADHD drugs come with warnings that the drugs can cause experiences typically labeled as hallucinations, mania, bipolar and psychosis, even in people taking normal prescribed doses and who have no previous history of, or risk factors for these experiences. The drug labels advise that these kinds of experiences were caused in 0.1% of children even after just a few weeks of use of stimulant drugs at normal doses – it is not known how common these side effects may be after years of use, or if the effects become permanent.

When not properly identified by prescribers as adverse effects of the ADHD drugs, these experiences could lead to a person receiving an additional diagnosis of Major Depressive Disorder, Bipolar Disorder or Schizophrenia, and being prescribed additional medications for these.


Related reading:

U.S. Food and Drug Administration. “Psychiatric Adverse Events Associated with Drug Treatment of ADHD: Review of Postmarketing Safety Data.” Department of Health and Human Services Public Health Service Food and Drug Administration Center For Drug Evaluation And Research. March 3, 2006.

Do ADHD drugs increase the risk of suicide?

The drug labels for some ADHD drugs come with explicit warnings that they can cause increases in suicidal feelings, thoughts, intentions and attempts.

Can ADHD drugs cause heart attacks?

A primary effect of ADHD drugs is significant acceleration or alteration of heart and cardiovascular functions in the human body. Large doses can therefore be very dangerous to the heart and cardiovascular system. According to their drug labels, ADHD drugs should not be prescribed to anyone with pre-existing heart or cardiovascular problems, because deaths are more likely to occur in these people. However, the labels also note that sudden deaths, strokes and heart attacks have been reported in association with many ADHD drugs even at normal dosage levels, and even in otherwise healthy people.

Are ADHD drugs safe to take during pregnancy or while breastfeeding?

All of the ADHD drugs come with warnings in their labels that these drugs have not been studied adequately in pregnant or breastfeeding women. Some of the labels warn about increased risks of premature delivery and low birth weight, and that infants may experience symptoms of drug withdrawal such as agitation, restlessness, listlessness and dysphoria. ADHD drugs interfere with the functioning of body and brain neurotransmitters, which are fundamental to fetal development, so it seems possible that there could be other risks of taking these drugs during pregnancy; there are studies showing a range of serious risks associated with pregnant women using stimulants recreationally.

Some of the side effects from psychiatric drugs seem to diminish over time – isn’t that a good thing?

When you complain about adverse effects after starting a psychiatric drug, it is common for physicians and psychiatrists to advise you to continue to take the drug anyway because some adverse effects will likely stop. Even popular medical websites like WebMD do this, advising that some of the adverse effects “may go away after you take the medicine for a while” because “your body can adjust” to the presence of the drugs.

This is certainly possible. What is not often explained, though, is that this body “adjustment” indicates growing drug tolerance. Your body is compensating for the presence of a foreign chemical and is developing ways to diminish some of the chemical’s impacts. So while you may begin experiencing fewer adverse effects or less intense adverse effects as your body compensates and adapts to the presence of the drug, it’s possible that you’ll begin experiencing decreased beneficial effects as well. And other adverse effects will often be continuing, if unnoticed.

Further, this increasing tolerance also indicates that your body is starting to develop physical dependence on the drug, which could bring the risk of uncomfortable, painful or even dangerous withdrawal symptoms if you try to stop the drug suddenly. Prescribers should warn patients more often about the risks of developing dependency on and tolerance to psychiatric drugs, but they often do not.

Are ADHD drugs addictive or dependence-forming even at normal dosages prescribed by my doctor?

All ADHD stimulant drugs come with strong FDA warnings that they are both addictive and dependence-forming. Addiction involves the development of “cravings” for a drug’s effects, and it most often develops when people take stimulants at levels above the recommended doses. However, even at the lowest recommended doses, ADHD stimulant drugs can still cause dependence to form. This means that over time the body and brain adjust and adapt to the presence of the drug, and people can experience a wide variety of withdrawal symptoms when they abruptly stop taking the drug. The drug labels for all stimulants warn about the risks of developing dependency. It is likely that the non-stimulant ADHD drugs also cause dependence, though at this time these drugs have not been as widely used or studied.

It is not fully understood how ADHD drugs affect the brain and body, and so it is also not understood exactly how abrupt discontinuation of these drugs can produce withdrawal symptoms after a period of regular use. However, it is known that ADHD drugs disrupt and alter the functioning of a number of major neurotransmitters (neurotransmitters are the key chemical messengers in the brain and body’s internal communications and functional systems). For example, ADHD stimulants seem to, at least in the beginning, increase the levels of the neurotransmitter dopamine in the brain. Human and animal studies have suggested that, over time, the body may then adjust to or compensate for this constant overload of dopamine by biologically reducing its sensitivity to dopamine and/or by reducing its own natural production of dopamine. Consequently, if a person then suddenly stops taking the drug, the person may experience a sudden, dramatic drop in dopamine levels that is unlike anything that would ever have naturally occurred before the person started taking the ADHD stimulant.

In other words, we could think of an ADHD drug as a sort of “gas pedal” creating higher dopamine levels in the body and brain. Over a period of time the body compensates by pressing more and more on its own internal dopamine “brake” system. Then, if the drug-driven dopamine gas pedal suddenly stops pressing, while the body’s own dopamine brake is still pressing hard, what happens? What are the mental and physical effects of this sudden, dramatic drop in dopamine levels on a person, especially when dopamine is involved in many different functions of the brain and body from cognition, emotion, motivation, attention and memory to sexual arousal and physical motor control? Further, ADHD drugs affect not only the activities of dopamine, but the activities of other neurotransmitters as well, including epinephrine (adrenaline), norepinephrine and serotonin. How are sudden changes to the activities of a host of major neurotransmitters experienced by a person, when those neurotransmitters are involved in virtually every physical, psychological, emotional and cognitive process in the brain and body?

Some of the most common symptoms of ADHD stimulant withdrawal include abdominal cramps, general aches and pains, nausea, insomnia, agitation, exhaustion, low mood, and extremely depressed feelings. Many of the drug labels also warn specifically about the possibility of prolonged and painful erections occurring during withdrawal.

If I want to stop taking ADHD drugs, what should I know?

There are virtually no formal scientific studies into the symptoms of prescription stimulant withdrawal or the safest methods or time frames for tapering.

Stopping any psychiatric drug can be risky or even dangerous. In particular, many official drug labels, formal scientific studies, and a growing evidence base of anecdotal reports from physicians and patients alike suggest that coming off psychiatric drugs abruptly or too rapidly for the central nervous system to manage tends to be especially risky and in some circumstances can even produce severe seizures or other life-threatening withdrawal reactions. Therefore, aside from situations where a medical emergency may deem rapid withdrawal to be necessary, tapering off a psychiatric drug is a major decision that is very personal and should involve forethought and careful planning. All of the possible benefits, risks and consequences of tapering should be carefully weighed in light of each individual’s life circumstances, physical health, resources, supports, and other factors.

If you or someone close to you is considering tapering, you may find it helpful to visit The Withdrawal Project, where ICI has been gathering the anecdotal reports and accumulated insights from laypeople who have experienced psychiatric drug withdrawal. There you can find discussions about common methods of tapering, what “slow” and “responsible” tapering looks like, how to prepare for tapering, and how to develop a plan of action for withdrawal that ideally involves the collaborative support of a well-informed prescriber, pharmacist, family and friends. At TWP Connect, people considering coming off psychiatric drugs can also connect with others who have experienced psychiatric drug withdrawal, are in withdrawal, or are considering withdrawal. (If you’re simply generally interested in connecting with others who are learning more and thinking critically about all things “mental health”, please consider joining ICI Connect.)