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Q: Long terms study regarding Ritalin ( Answered,   0 Comments )
Subject: Long terms study regarding Ritalin
Category: Health > Children
Asked by: buddysystems-ga
List Price: $25.00
Posted: 25 Sep 2005 07:37 PDT
Expires: 25 Oct 2005 07:37 PDT
Question ID: 572351
Long terms study regarding the effects of use of Methylphenidate
(Ritalin) or similar drugs on mental health of patients
Subject: Re: Long terms study regarding Ritalin
Answered By: welte-ga on 26 Sep 2005 08:04 PDT
Hi buddysystems-ga, and thanks for your question.

As you likely know, there are very few long term studies of the
effects of methylphenidate.  One of the longest followup studies was
conducted by Charac, et al., from the Hospital for Sick Children in
Toronto.  Their article nicely summarizes what is currently known
about the long term side effects (both mental and physical):

"In addition to unanswered questions about the long-term benefits of
chronic stimulant use, questions remain about its long-term side
effect profile and overall safety. In a recent report, Jadad et al.
(1999) indicated that the cumulative physiological effects of
children?s use of chronic stimulants are poorly documented. The side
effects studied most frequently have been sleep disorders, headaches,
motor tics, decreased appetite, stomach pain, nausea, and irritability
(Jadad et al., 1999). Some adverse effects, such as overfocusing or
listlessness, occur at the time of peak pharmacological activity and
seem to be an exaggeration of the desired effect of MPH (Ahmann et
al., 1993). These physiologic effects may not represent safety
concerns as such; however, unwanted side effects can interfere with
treatment adherence. Schachar et al. (1997) found that 15% of children
treated with MPH terminated treatment by 4 months because of side
effects. For 50% of these children, the side effects that led to
discontinuing medication were not a problem until the children had
been treated for several months. More specifically, it is important to
identify late-onset adverse effects that may arise with chronic
stimulant use. Law and Schachar (1999) took a close look at one type
of adverse event, the development of tics, and noted that tics
occurred with similar frequencies in children taking placebo and
children taking MPH. However, they reported two cases of new-onset
Tourette-like symptoms that occurred between 4 and 12 months after
initiation of treatment (Law and Schachar, 1999). These observations
document the importance of identifying adverse effects that may appear
after months or years of stimulant use."

Charach A. Ickowicz A. Schachar R. Stimulant treatment over five
years: adherence, effectiveness, and adverse effects. [Clinical Trial.
Journal Article. Randomized Controlled Trial] Journal of the American
Academy of Child & Adolescent Psychiatry. 43(5):559-67, 2004 May.
UI: 15100562

This article is not freely available, but you can request a reprint
from Dr. Charach at this address:

There has also been some discussion in the literature regarding growth
retardation and other physical side effects of treatment. 
Unfortunately, these controversies have not yet been resolved.  The
authors of the above article summarize the situation:

"Recent evidence suggests that children with ADHD show delayed growth
(Spencer et al., 1998), have more tics (Barkley et al., 1990b ; Law
and Schachar, 1999), experience sleep disorders (Corkum et al., 1998;
Picchietti et al., 1998), and develop substance use disorders in
adolescence (Barkley et al., 1990a; Biederman et al., 1999) more often
than other children, independent of their exposure to
psychostimulants. However, little long-term evidence is available, and
controversy remains about whether these conditions are worsened by
stimulant use."

The authors state that the most prominent long term side effect was
decreased appetite:

"The current data also documented that stimulant medications continued
to cause adverse effects for up to 5 years. Some physiological adverse
effects, especially decreased appetite, seemed to be tolerated over
time, as many children who experienced it continued to take medication
anyway. The adverse effects documented are in general relatively mild
and of little health concern."

Figure 1 from the above article compares patients adherent vs. those
who were not adherent to therapy over the course of 5 years with
regard to physiological side effects, affective side effects,
overfocusing, and development of tics.  In terms of mental health side
effects (affective and overfocusing), there was no clinically
significant difference found at 5 years.


A second article with a shorter followup period (12 months) also
looked at methylphenidate efficacy and side effects.  The authors
again state that there is a small amount of information available on
the long term efficacy and side effects of this drug:

"Despite a robust body of literature on the short-term effects of
stimulant medications (Goldman et al., 1998), a paucity of studies is
available on the long-term effects of these medications in youths with
ADHD. Emerging data suggest that longer-term treatment of ADHD results
in improved academic and social functioning (Gillberg et al.,
1997;MTA, 1999) and reduced sequelae such as the development of
psychiatric disorders (MTA, 1999) and substance abuse (Biederman et
al., 1999;Wilens et al., 2003). Thus long-term treatment and the
issues of acceptability, sustained effectiveness, and tolerability
become paramount."

Wilens T. Pelham W. Stein M. Conners CK. Abikoff H. Atkins M. August
G. Greenhill L. McBurnett K. Palumbo D. Swanson J. Wolraich M. ADHD
treatment with once-daily OROS methylphenidate: interim 12-month
results from a long-term open-label study. [Clinical Trial. Journal
Article. Multicenter Study] Journal of the American Academy of Child &
Adolescent Psychiatry. 42(4):424-33, 2003 Apr.
UI: 12649629

Again, this article is not freely available, but a reprint can be
requested from Dr. Wilens:

This article is an interim report, with its ultimate followup goal
being 24 months.  The study again looked at the effect of this drug on
growth, and found no significant effect:

"Issues of weight and height deficits with long-term stimulant
treatment remain of great concern (Spencer et al., 1998). In the
current study, mean absolute weight decreased by 0.1 kg during the
first 3 months of the study, then showed a steady increase of 2.7 kg
over the remainder of the study. The growth in weight between months 4
and 12 approximated that expected for the represented age group
(Kuczmarski et al., 2000). Mean absolute height increased throughout
the entire 12-month study period, from 137.1 cm at baseline to 142.3
cm at month 12, approximating the 5.0-cm growth expected for this age
group over a 1-year period (Kuczmarski et al., 2000). Clearly, further
analyses of growth in children in this study and other longitudinal
studies are necessary..."

"Findings from the current study appear consistent with recent
literature indicating a lack of long-term height/weight issues related
to MPH."

With regard to mental health side effects, the most relevant endpoint
measured by this group would be side effects involving sleep, for
which they found no effect:

"No deleterious effects of OROS MPH were found for appetite, growth,
sleep, tic onset/exacerbation, vital signs, or laboratory results over
the 1-year study."


A third group from the University of Maryland reviewed the toxicology
and side effect profile of methylphenidate, looking at multiple
studies.  They found that the drug has a favorable side effect

"Adverse effects of methylphenidate therapy

Methylphenidate's margin of safety is high. Side effects increase
linearly with dose and are more likely with daily methylphenidate
doses larger than 2 mg/kg [4,7]. Therefore, decreasing the dose or
changing the spacing between doses will usually minimize adverse
effects [1]. Common adverse effects include insomnia, nervousness,
irritability, anxiety, jitteriness, headache, stomachache, and
anorexia. Palpitations, tachycardia, and increases in diastolic and
systolic blood pressure can occur. Increase in heart rate is a
dose-related adverse effect [8]. Despite concerns regarding
methylphenidate-associated tics, usual doses of methylphenidate
probably do not exacerbate or precipitate tic disorders in most
children [9,10]. Chronic use of methylphenidate decreases growth, but
long-term effects on weight and height are generally not considered
significant [11,12]."

The group also found that methylphenidate has potential for abuse
(known on the street as vitamin R, R-ball, and Skippy), something
which has been on the rise by individuals without ADHD obtaining
Ritalin and those taking the drug who overdose or share with friends
or siblings:

"There are concerns that methylphenidate is being diverted from
legitimate use and that abuse is on the rise among preteens, teens,
and college students. Many published reports of methylphenidate
toxicity involve methylphenidate abuse. Although methylphenidate has
abuse potential, there is disagreement about the extent to which it is
being abused. Data from the US Drug Enforcement Agency and media
suggest that methylphenidate abuse is becoming a significant problem.
Production of methylphenidate, a schedule II controlled substance with
strict government quotas on the quantity manufactured, increased
eightfold between 1990 and 1999 [15?]. In 1995, the Drug Enforcement
Agency reported a 600% increase in methylphenidate prescriptions since
1990 [16]. There was a sixfold increase in methylphenidate mentions to
the Drug Abuse Warning Network between 1990 and 1995. A study of 161
students on methylphenidate found that 16% of the 73 survey
respondents had been asked by other students to trade, sell, or give
them their stimulant medication [17]. In 48 of 60 animal and human
studies analyzed to assess methylphenidate's abuse potential,
methylphenidate was found to cause reinforcing,
discriminative-stimulus, or subjective effects comparable with those
caused by d-amphetamine or cocaine [15?]. In nondrug-abusing
volunteers, methylphenidate has been shown to function as a
reinforcer, a strong predictor of abuse potential [18]."

Abusers of methylphenidate also suffer withdrawal:

"After chronic abuse of methylphenidate, withdrawal symptoms include
lethargy, apathy, depression, and paranoia [34]. These symptoms are
similar to those of withdrawal from amphetamines."


Another group from SUNY Stony Brook looked at methylphenidate in
children with ADHD and chronic tic disorder for a period of 2 years. 
This study looked primarily at whether or not this drug makes tic
disorder worse, and found no significant effect:

" Long-term treatment with methylphenidate seems to be safe and
effective for the management of ADHD behaviors in many (but not
necessarily all) children with mild to moderate tic disorder.
Nevertheless, careful clinical monitoring is mandatory to rule out the
possibility of drug-induced tic exacerbation in individual patients."

Gadow KD. Sverd J. Sprafkin J. Nolan EE. Grossman S. Long-term
methylphenidate therapy in children with comorbid attention-deficit
hyperactivity disorder and chronic multiple tic disorder.[see
comment]. [Clinical Trial. Controlled Clinical Trial. Journal Article]
Archives of General Psychiatry. 56(4):330-6, 1999 Apr.
UI: 10197827

Again, this article is not freely available, but can be purchased here:

You can also request a reprint from Dr. Gadow:


There have been several stories in the news lately about the potential
applicability of animal (rat) studies to humans.  Here's an article
from Medical News Today with a good summary of the concerns:

As the article states, there is concern that use of methylphenidate in
adolescent rats resulted in changes in brain architecture.  What this
means and whether or not it has anything to do with the effects of
this drug in humans is still an open question.

Here is an additional news article similar to the above:

Here is a Google News search for methylphenidate and "long term,"
which will be automatically updated as new news results appear:


This is an vigorously ongoing area of research, and everyone agrees
that more information is needed on the long term effects of this drug.
 New research findings will no doubt be forthcoming in the next few
years.  Keeping an eye on the press is one way to keep up on this
information, although you obviously get a filtered view of the
research results.

You can also set up PubMed to scan the medical literature
periodically:  Set up a "My NCBI" account (free), perform a search
(e.g. methylphenidate), then click on "Save Search" to the right of
the search box.  You will be asked if you'd like e-mail updates on
this search.  If you click "yes," you will be asked how often you'd
like updates.  Here's the main site:

I hope this information was useful.  Please feel free to request any clarification.


There are no comments at this time.

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