What is ADHD?

Possible side effects of methylphenidate

Psychiatric outcomes

Concerns have been raised in both the scientific literature and mass media that treatment with methylphenidate can result in a range of adverse psychiatric outcomes. Unfortunately the evidence to support these claims is not strong and several important questions remain unanswered.

MOOD DISORDERS

Clinical experience suggests that low mood is a real but relatively uncommon adverse effect in those taking methylphenidate. Research evidence on these issues is limited. Also data are confounded by the fact that depression and mood lability are common in those with ADHD irrespective of whether they are receiving medication or not. ADDUCE will investigate the link between treatment with metylphenidate and mood disorders.

PSYCHOSIS Hallucinations and other psychotic symptoms have been reported in children taking methylphenidate but the extent of this and whether methylphenidate is the cause remains unclear. There is a lack of long-term evidence in representative populations. ADDUCE will address these issues within the current study.

SUICIDE Data from the atomoxetine (e.g. Strattera) clinical trials database identified a small but statistically significant increased risk of suicidal thoughts among atomoxetine-treated children and adolescents compared with patients taking placebo. However, a recent review of the safety literature for ADHD medications found no evidence to suggest that methylphenidate is associated with an increased risk of suicidal thoughts or acts but this is due to a lack of evidence rather than convincing evidence of an absence of risk. ADDUCE will address this in the present study.

TICS AND TOURETTE DISORDER Studies indicate that in 5-10% of cases, tics may get worse in patients treated with metylphenidate. This effect is usually reversible once they stop taking the medication. However, more evidence is needed. ADDUCE will systematically assess tics using reliable, validated measures in ADHD patients treated with methylphenidate and in untreated ADHD controls.

SUBSTANCE MISUSE Findings from animal studies suggest that the rewarding properties of methylphenidate are diminished by prior exposure to the drug, and this may increase the risk of later substance misuse. On the other hand, the timing of initial exposure to metylphenidate seems to be an important factor. For instance, whilst metylphenidate treatment in adolescent or adult rats was associated with increased levels of subsequent drug abuse, treatment in preadolescent rats produced the opposite result. Clinical surveillance of humans has not yet established an influence of either short term or long-term use of methylphenidate on substance misuse, as it is difficult to establish the level of substance misuse by an individual. It is also probable that substance misuse is associated with ADHD even in the absence of stimulant medication, and that the presence of conduct disorder can be an additional complicating factor. ADDUCE will use standardised measures of substance use/misuse to address these issues.

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News

The fifth ADDUCE Newsletter is now available!

Here, you can read about the finalisation of the project,

the European Medicines Agency and General Assembly meetings

and the dissemination of the results!

The fourth ADDUCE Newsletter is available!

In this newsletter, you can find some information on the final recruitment status of the 2 main studies:

- the prospective open-label methylphenidate pharmacovigilance study

- the long-term cardiascular effects of methylphenidate use

Also, you can read about the future plans of the project!

More than 1500 children, adolescents and adults across all Europe already took part in our study! Thanks to them, we have already gathered lots of information so we can know a lot more about methylphenidate than ever before!