Some commonly prescribed ADHD drugs
The drugs (sometimes referred to as psychostimulants) used to treat so-called ADHD are usually
amphetamines and amphetamine-like substances; as such, they are not really specific treatments to counter
hyperactivity, distraction and/or impulsivity; neither do they correct a chemical imbalance in the brain.
You may have heard of drugs like Ritalin (methylphenidate) and Concerta the extended-release version. It is in
fact a drug very similar to cocaine. Focalin (dexmethylphenidate) is a form of methylphenidate and also comes
in a long-acting formulation. Strattera (atomoxetine) and dexamphetamine (as the name indicates, is
amphetamine) are also used here in the UK. Although Strattera is marketed by the maker (Eli Lilly) as a non-
stimulant it shares most of the adverse effects associated with stimulant drugs like Ritalin 1. Cylert,
previously prescribed for ADHD, was removed from UK market around 15 years ago and has been associated
with liver toxicity and death 2.
Studies show stimulant drugs are not as effective or safe as the marketing hype
One particular study on stimulant drugs (as used for ADHD-type behaviours) seems to have had quite an
impact on persuading many people (doctors and teachers included) that these drugs are effective with so-
called ADHD: this is the Multimodal Treatment Study of Children with ADHD (MTA 1999. Abstract here).
Although the study results did seem to show improvement with attention and reduced activity levels in the
short-term, the follow up studies did not paint the same picture: at the end of 6 years the patients were showing
“worse hyperactivity-impulsivity” 3. Note, these are the very behaviours the drugs were intended to
alleviate. And, as Prof Alan Sroufe rightly concludes, "by eight years there was no evidence that medication
produced any academic or behavioral benefits."
It is also worth noting that there are numerous methodological problems with the MTA study which was
conducted with a bias that is likely to favour the drug treatments 4. Although it is sometimes claimed that
Ritalin and similar drugs help with learning, the study also “failed to indicate any beneficial effects on school
performance or family relations 5.”
A report based on a review (by researchers at Oregon University, available here 6) of nearly 300
publications on stimulant drugs showed that trials testing the drugs tended to be of poor quality, very small and
of short duration. Noticeably, the very matters that parents would like to know more about were inadequately
addressed by the studies or simply scored poorly. So the evidence for the drugs’ safety and ability to show that
the drugs make real life changes - academically and socially - were poor. In addition, there was a distinct lack
of comparisons between one drug and another.
The Oregon study showed conflicting reports as to whether or not use of childhood stimulant drugs was likely
to lead to later drug abuse. Interestingly, one doctor (Biederman) reported a later reduced likelihood for
substance abuse following earlier use of ADHD meds. It is however, important to note that Dr Biederman’s
credibility and reliability have been discredited in that he initially failed to disclose drug company payments of
over $1 million. (The discrepancies between what Biederman disclosed as consultancy income from drug
companies and the payments he actually received are shown here in the New York Times). Another researcher
(Lambert) did find significantly increased odds of tobacco and cocaine and/or amphetamine dependence later
on among those who had used stimulants as children 6.
Do children diagnosed as ADHD really have smaller brains?
In 2002 the National Institute of Mental Health issued a press release: “A 10-year study by National Institute of
Mental Health (NIMH) scientists has found that brains of children and adolescents with Attention Deficit
Hyperactivity Disorder (ADHD) are 3-4 percent smaller than those of children who don't have the disorder —
and that medication treatment is not the cause.” Wow, that’s some claim, that ADHD diagnosed children have
smaller brains. It’s an important study result for those people pro-stimulant drugs as it appears to counter a
claim that the ADHD drugs cause brain shrinkage – so now we know it’s the “disease” not the drugs that
causes this. Well, that’s the assertion in the study often referred to as the Castellanos Study (after one of the
authors, Dr Xavier Castellanos).
We have already looked at the research that misleadingly claimed that a genetic basis for so-called ADHD has
been discovered, under this heading: Beware of misleading press reports making unfounded claims, located in
this website here .
Dr Grace Jackson points out numerous methodological weaknesses with regard to the Castellanos study,
including the fact that “the NIMH team repeatedly compared the features of older, medicated children with
unmedicated patients who were 2½ years younger (and, hence 2½ years behind them in brain development)”
8. Not surprisingly, the stimulant damage would be less apparent when less developed (smaller) brains were
compared with those stunted by stimulant medications. Professors Leo and Cohen similarly have asked: “Why
is the control group two years older, taller, and heavier than the group of unmedicated patients? It seems odd
that, given ten years and the resources of the NIMH these experienced researchers could not find a more
appropriate control group…The issue of height and weight is especially relevant here because most research
on brain size has found brain size to be correlated with body weight 9.”
Side-effects of ADHD medications
Before taking a closer look at some more of the risks of these ADHD medications, we will consider some of the
possible (and in some cases, likely) ill-effects of these drugs on the child. As the drug effects wear off between
doses there may be withdrawal effects that resemble the behaviours, like hyperactivity, that the doctors intend
to treat with the drugs. Parents and teachers so often take this to reinforce the idea that the children need
these drugs: misconstruing these behaviours and moods as an underlying disorder that needs to be
medicated. The side-effects listed below are based on the following references: 1, 10, 11, 12, 13,
14, 15 , 16, 17. These are some of the possible costs (see also the Safety concerns I mention on
further below) borne by the child or young person taking these drugs.
- Psychosis (and may hallucinate)
- A distinct drug rebound with the drug-effect wearing off between doses. This can be confused with the
original behaviours that lead to the drug being prescribed (including hyperactivity)
- Emotionally bland – “zombie-like”
- Reduced creativity
- Tourettes or other tic syndromes
- Increased blood pressure and heart rate
- Cardiac arrhythmias
- Gastrointestinal symptoms e.g. vomiting, stomach pain
- Poor appetite
- Weight loss
- Mood swings
- Growth suppression, and slower rate of physical development during puberty (Consider the
- Blurred vision
- Increased sadness
- Quietens some children
- Agitation (sometimes hyperactivity)
- Obsessive compulsive behaviour (OCD)
- Personality changes
- Feeling suicidal
- Less able to control their emotions
- Social isolation, becoming more detached and lonesome
- Chance of seizures increased (epileptic fits)
Safety concerns of ADHD medications
The big issue is – we don’t know enough about long-term use of ADHD drugs
A closer look at the data on ADHD drugs shows a number of serious safety concerns. When it comes to drugs
like Ritalin (methylphenidate) we really don’t know the long-term effects. Methylphenidate has been approved
for human use for over 50 years and yet “there are surprisingly few studies on the potential for serious side
effects, such as mutagenicity, and carcinogenicity, in animals or in humans 18.” Put simply, there is
insufficient research to assure parents and children that these drugs will not later on lead to cancer through
damaging cells. This study concludes: “the lack of research on the long-term effects of methylphenidate use in
humans warrants great concern. At present, it is not clear what the long-term effects would be for children who
took methylphenidate 10 or 20 years ago or for those who are currently being treated with this drug.” The
study did discover that liver tumours developed in mice with prolonged use of methylphenidate/Ritalin. It is
worth bearing in mind that rodents share a high degree of genetic similarity to humans 8. What we do know
is that “Repeated exposure to methylphenidate in early life affects a variety of behavioural and physiological
responses in adulthood 19.”
Ritalin has not been evaluated for long-term use (over 12 months) in children and adolescents
Although these drugs are often used for some years, there aren’t long-term trials supporting this practise.
According to the maker of Ritalin/methyphenidate (Novartis), “The safety and efficacy of long term use of
methylphenidate has not been systematically evaluated in controlled trials. Methylphenidate treatment should
not and need not be indefinite 20.”
Just because they are prescribed drugs does not mean that they are not addictive
People readily associate street drugs such as cocaine or speed as addictive. And yet, because ADHD drugs
are prescribed by a doctor, it is too easy to assume they are less likely to be addictive. We forget that these
drugs are close relatives of these illicit drugs. “Tolerance, in which more and more drug is needed to produce
the usual effects, can develop rapidly, and psychological dependence occurs. In fact, the strongest
psychological dependence observed occurs with the more potent stimulants, such as amphetamine,
methylphenidate, methamphetamine, cocaine and methcathinone. Abrupt cessation is commonly followed by
depression, anxiety, drug craving, and extreme fatigue, known as a ‘crash’ 21.” Thus, as with ‘recreational’
stimulants, these drugs are known to induce tolerance with continued use; for the same effects, the dose has
to be increased. This means that ever-increasing doses will be necessary to maintain the early effects that are
perceived as beneficial 5.
Methylphenidate has a chemical structure similar to that of cocaine and thus acts on the brain in a very similar
way: “Cocaine, which is one of the most reinforcing and addictive of the abused drugs, has pharmacological
actions that are very similar to those of methylphenidate” 22. In fact, as the psychopharmacologist Richard
DeGrandpre writes, “All else being equal, Ritalin is nothing less than synthetic cocaine” 23 and its
“pharmacology is more akin to cocaine than amphetamines”. Not surprisingly, methylphenidate (Ritalin) is used
(crushed and snorted) illegally as a recreational drug. When used intravenously, “Ritalin is about twice as
potent as cocaine”11.
The fact that Ritalin is a prescribed drug does not mean that it is safe or less addictive. Richard DeGrandpre
makes a pertinent point: “either cocaine is not the inherent demon drug it was made out to be, or Ritalin is
incorrigibly evil and corrupting 23”.
According to the FDA, “Adolescents with ADHD, especially when untreated, are at greater risk of substance
abuse” 24. So give them addictive drugs - amphetamines!! It seems quite bizarre: putting youngsters on
drugs to keep them off drugs. Not surprisingly, higher rates of substance abuse are later on associated with
those who as children were prescribed stimulants. They have an increased likelihood of becoming dependent
on stimulant drugs such as cocaine and amphetamine (and of becoming a regular smoker) 5.
Animal studies indicate childhood use of ADHD drugs could lead to later brain damage
Dr Jackson points out that (in this study here 25) just a single injection of methylphenidate resulted in a 5-
fold increase in cell death when administered to a mouse pup.
A further rodent study (this time with rats) showed that Ritalin reduces brain cell (neurons) fibre density. The
purpose of the study was to better understand the consequences of the childhood use of Ritalin.
Note the title of this study:
Methylphenidate administration to juvenile rats alters brain areas involved in
cognition, motivated behaviours, appetite, and stress 26. Based on this research, Dr Grace Jackson
concludes that early use of methylphenidate “impairs the growth and/or survival of neurons in brain regions
which are considered to be essential for judgement, impulse control, learning, memory, and movement 8.”
Based on this study, Dr Jackson comments: “the results of this experiment strongly suggests that
methylphenidate is a brain teratogen 8.” [teratogen: a drug or other substance capable of interfering with
the development of a foetus, causing birth defects.]
Risk of psychosis from stimulant meds
“Psychotic symptoms are well-known side effects of all stimulant medications” 27. In the US the FDA issued a
memorandum 28 warning that any of the drugs currently used to treat “ADHD” can lead patients to suffer
from mania or psychosis (including experiencing hallucinations). This is consistent with reports by US pilots of
hallucinations and delusions with the use of so-called combat amphetamines 11.
Stimulant drugs can cause depression
Stimulant drugs can cause depression 10; so starting a child on stimulant drugs can lead to antidepressants
also being prescribed. There is then added risks as different drugs are not usually tested together.
Stimulants damage the brain
“For almost 70 years, children have received stimulants for the treatment of ADHD…with little understanding of
the long-term effects of those drugs on brain development...The effects of stimulant drugs during different
stages of this process have unique short-term, acute effects that also influence long-term effects. Chronic,
pre-pubertal exposure alters the expected development trajectory of brain structure and function and results in
a different topography in adulthood 29.”
As “each brain zone has its own unique schedule of development” 8 different brain regions mature at
different rates. The extent of the damage from hindering the child’s brain at critical stages of development is
not fully understood.
Research shows that “There is reason to be concerned about brain tissue shrinkage as a result of long-term
Ritalin therapy 1”. The use of amphetamines have also been shown to lead to structural changes in parts of
the brain 30.
It is worth bearing in mind that as sustained-release stimulants provide a steady release of the drug to the
brain, “the brain has less opportunity to bounce back or recover” so long-acting ones are “likely to produce
more harm to the brain” 31 than shorter-acting ones.
Cardiovascular risks and sudden death
Dr Steven Nissen, an eminent cardiologist warns that the amphetamine drugs used to treat so-called ADHD
“substantially increase the heart rate and blood pressure” which can of course lead to cardiovascular
problems, particularly with those with a specific vulnerability 32.
A report published by the Australian Dept of Health states that: “Based on the findings of this research, it is
now well accepted that both methylphenidate and dexamphetamine result in statistically significant increases
in blood pressure and heart rate…and the long-term implications of the cardiovascular effects of stimulant
medication-use over a number of years have not yet been adequately explored 33.”
This study investigated the fact that some children taking stimulant medications died suddenly. Their
conclusion was: “This case-control study provides support for an association between the use of stimulants
and sudden unexplained death among children and adolescents. Although sudden unexplained death is a
rare event, this finding should be considered in the context of other data about the risk and benefit of
stimulants in medical treatment 36.”
Clonidine (a drug used to treat migraines and also for high blood pressure in adults, see here) is sometimes
prescribed for children diagnosed as ADHD. It is sometimes used in conjunction with a stimulant drug and
“prescribed to children as a sleep aid and calming agent, especially to counteract the activating effects of
stimulants. When mistakenly prescribed with stimulants, it causes an elevated risk of cardiac arrest." 39
A brief word about Strattera (atomoxetine)
Strattera is marketed by the manufacturer (Eli Lilly) as a non-stimulant drug; unfortunately, this can
misleadingly give the impression that this drug is a safer option. In 2011 Lilly issued a safety notice warning
about "the risk of increased blood pressure and increased
heart rate with the use of Strattera (atomoxetine)".
Also, a letter to the editor of the journal of the Academy of Pediatrics raised concerns over extreme irritability,
aggression, mania and mood de-stabilisation in relation to the use of Strattera with youngsters 34.
According to Dr Breggin, Strattera has been promoted by Lilly as “especially safe, when it is in fact especially
dangerous 1." Furthermore, a meta-analysis showed that “atomoxetine was associated with significantly
higher risk of suicidal ideation than placebo 6.”
The drug label (patient and doctor information) for Strattera warns in sec 5.5:
"Treatment emergent psychotic or manic symptoms, e.g., hallucinations, delusional thinking, or mania in children
and adolescents without a prior history of psychotic illness or mania can be caused by atomoxetine at usual
doses." (See the drug label here).
Do the benefits outweigh the risks?
The long-term benefits and long-term risks are central factors when deciding whether or not to start a child on
stimulant medications. Not only have long-term benefits from stimulants been difficult to demonstrate in
controlled trials 17, but, over time, children have been shown to perform worse academically too: “In
children with ADHD, ever receiving stimulant medication was found to increase the odds of being identified as
performing below age-level by a classroom teacher by a factor of 10.5 times (compared to never receiving
stimulant medication) 33.”
You will be familiar with students using amphetamine-type drugs to help focus on
exams. A press release
the American Academy of Neurology raises serious
concerns about ADHD-type drugs as used by
children to boost cognitive function
(sometimes described as "neuroenhancements"). The reasons given
long-term health and safety of neuroenhancements, which has not been studied in
the risk...of dependency.37." Clinical guidance, also from the
American Academy of Neurology, adds
concerns over the effect on the child's
"developing brain"38. This is a clear acknowledgement by
neurologists that these
drugs are dangerous, addictive and not properly studied for risks. Prescribing them
for children with the ill-founded ADHD diagnosis is not going to make these same drugs safe or non-addictive.
However, please note the safety warning above about changing drug doses (and/or stopping) these drugs.
As we have seen, concerns about these medications are very real. With this in mind it makes sense to
carefully consider alternative ways of dealing with inattenitve, hyperactive and distracted youngsters. This
will do here.
References - Bibliography - Further reading
1 Breggin, P. (2008) Brain-Disabling Treatments in Psychiatry. New York: Springer Books
2 Bremner, J. D. (2008) Before You Take That Pill. London: Penguin Books.
3 Molina, B et al. 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 (2009):484-500.
4 Breggin, P. (2000) The NIMH multinodal study of treatment for ADHD: A critical analysis. International Center for the Study
of Psychiatry and Psychology Journal. Available here.
5 Moncrieff, J. (2009) A Straight Talking Introduction to Psychiatric Drugs. UK: PCCS Books Ltd
6 McDonagh, M et al (2007) Drug Class Review on Pharmacologic Treatments for ADHD. Oregon Health & Science
University. Available here.
8 Jackson, G. (2009) Drug-induced dementia - a perfect crime. USA: Anchor House
9 Leo, J. & Cohen, D. (2003) Broken brains or flawed studies? A critical review of ADHD neuroimaging research. The
Journal of Mind & Behavior Vol 24 No 1
10 Breggin, P. (2001) The Antidepressant Fact Book. US: Da Capo Press
11 Jackson, G. (2005) Rethinking Psychiatric Drugs. USA: Anchor House
12 Timimi, S. (2002) Pathological Child Psychiatry. UK: Brunner-Routledge
13 Breggin, P. (2001) Talking Back to Ritalin. US: Da Capo Press
14 Baughman, F. (2006) The ADHD Fraud. Canada: Trafford Publishing
15 Timimi, S. (2004) Developing non-toxic approaches to helping children who could be diagnosed with ADHD and their
families: Reflections of a UK clinician. Ethical Human Psychology and Psychiatry, 6, 41-52.
16 Breggin, P. & Cohen. D. 2007 (Update of 1999) Your Drug May Be Your Problem. US: Da Capo Press
17 Moncrieff, J. (2008) The Myth of the Chemical Cure. UK: Palgrave MacMillan
18 El-Zein, R.A. et al (2005) Cytogenetic effects in children treated with methylphenidate. Science Direct, Pub by Elsevier
Ireland Ltd. Full study available here.
19 Legrace, D.C. et al 2006 Juvenile administration of methylphenidate attenuates adult hippocampal neurogenesis.
Biological Psychiatry 2006;60:1121-1130. Available here. p. 1126
20 See sec 4.4 Special warnings and precautions, at Novartis here (accessed 14.01.13)
21 US Drug Enforcement Administration, Stimulant Drugs Factsheet. Available here
22 N. D. Volkow et al. Is methyphenidate like cocaine? Studies on their pharmacokinetics and distribution in the human
brain, Archives of General Psychiatry, 52 (1995): 350
23 DeGrandpre, R. (2006) The Cult of Pharmacology. USA: Duke University Press
24 ADHD: US Clinical Practice Guideline for the Diagnosis, Evaluation, and Treatment of Attention-Deficit/Hyperactivity
Disorder in Children and Adolescents. Pediatrics 2001. Available here.
25 Husson et al. (2004) Methylphenidate and MK-801, an N-methyl-d-aspartate receptor antagonist: shared biological
properties. Neuroscience 2004;125(1):163-70
26 Gray, J. D. et al (2007) Methylphenidate administration to juvenile rats alters brain areas involved in cognition, motivated
behaviours, appetite, and stress. The Journal of Neuroscience.
27 Cherland, E. & Fitzpatrick, R. (1999) Psychotic side effects of psychostimulants: A 5-year review. Canadian Journal
Psychiatry 1999; 44:811-813. Available here.
28 Dept. of Health and Human Services Public Health Service Food and Drug Administration Center for Drug Evaluation and
Research. March 3, 2006. Available here.
29 Anderson, S.L. (2005) Stimulants and the developing brain. Trends Pharmacol Sci. 2005 May;26(5):237-43.
30 Robinson, T.E. & Kolg, B. (1997) Persistent Structural Modifications in Nucleus Accumbens and Prefrontal Cortex
Neurons Produced by Previous Experience with Amphetamine. The Journal of Neuroscience, November 1, 1997,
17(21):8491–8497. Available here.
31 Breggin, P. (2002) The Ritalin Fact Book. US: Perseus Publishing
32 Nissen, S.E. (2006) ADHD Drugs and Cardiovascular Risk. New England Journal of Medicine. Available here.
33 Raine ADHD Study: Long-term outcomes associated with stimulant medication in the treatment of ADHD in children.
(2010) Available here. Govt of Western Australia Dept of Health p.12
34 Madelyn S. Gould et al. (2009) Sudden Death and Use of Stimulant Medications in Youths. Am J Psychiatry 2009;
166:992-1001. Abstract available here.
35 Poulton, A. et al. (2013) Growth and pubertal development of adolescent boys on stimulant medication for attention deficit
hyperactivity disorder. Med J Aust 2013; 198 (1): 29-32. Available here.
36 Henderson, T. & Hartman, K. (2004) Aggression, Mania, and Hypomania Induction Associated With Atomoxetine
Pediatrics Vol. 114 No. 3. Available here.
37 American Academy of Neurology: Press release March 13 2013. Doctors Caution Against Prescribing Attention-Boosting
Drugs for Healthy Kids
38 American Academy of Neurology (2009). Responding to requests from adult patients
Ethics, Law and Humanities Committee. PDF Available here.
39 Breggin, P. (2013) Psychiatric Drug Withdrawal. New York: Springer Publishing Company.