Think twice before prescribing for ADHD

LATE last year, The BMJ published a systematic (Cochrane) review of the efficacy of methylphenidate for children and adolescents with a diagnosis of attention deficit hyperactivity disorder (ADHD).

The results were reported as suggesting that “methylphenidate may improve teacher-reported symptoms of ADHD and general behaviour and parent-reported quality of life”. But the authors also noted that virtually all the trials on which they based their conclusions were of very low quality and likely to be biased.

Nevertheless, many would take reassurance from the fact that this Cochrane review did not find a statistically significant increase in severe adverse outcomes. However, such conventional meta-analyses will underestimate harms because adverse events are generally poorly documented in randomised controlled trials.

This failure is one manifestation of an unacceptable lack of proper pharmacovigilance, whereby regulators, such as the Therapeutic Goods Administration (TGA) in Australia or the Food and Drug Administration (FDA) in the United States, pharmaceutical companies and doctors alike are poor at collecting and analysing adverse events from drugs.

A recent MJA article by Cairns and colleagues is therefore vital. The authors analysed intentional exposures to drugs used for ADHD (methylphenidate, dexamphetamine, modafinil and atomoxetine) reported to the New South Wales Poisons Information Centre (NSWPIC) from 2004 to 2014. During this 11-year study period, there were 1735 reports of overdoses or recreational use, 93% of which were severe enough to require hospitalisation. Increases in the rate of misuse over that decade correlated with increases in the rate of prescription. Of course, there is no evidence that the stimulant itself led to the dangerous behaviour; it may just have been the most convenient drug to hand.

• Related: MJA -- ADHD and psychostimulants — overdiagnosis and overprescription
• Related: MJA InSight -- ADHD meds + party drugs “complex cocktail”
• Related: MJA -- ADHD medication overdose and misuse: the NSW Poisons Information Centre experience, 2004–2014

The authors made a rough distinction between likely self-injurious behaviour and illicit use (defining the latter as co-ingestion with alcohol or a street drug). While these drugs may also be part of a self-harm overdose, this approach seems reasonable.

Likely illicit use constituted 10% of intoxications overall, increasing to 20% in 2014. Furthermore, the authors provide evidence from other sources that most of the stimulants that are used as intoxicants are diverted from patients to others for whom they are not prescribed.

So how should a parent respond to a suggestion that their child has ADHD and should be treated with methylphenidate?

First, they should, with their doctor, seek a better explanation of why their child is overactive, inattentive or impulsive, rather than calling it ADHD.

That label really just amounts to a dumbed-down shorthand signalling pattern-recognition of one way in which a child can manifest or communicate that he/she is not managing.

It is far more productive to explore the child’s particular predicament and to try to intervene as appropriate with the individual, family and educational system. 

Some argue that the ADHD label, while merely descriptive, confers benefit through increased access to services and a reduction in blaming the child or family for the child’s behaviour. But against this needs to be balanced the potential for the ADHD diagnosis to distract the medical system and family from seeking more meaningful explanations, and the real loss of autonomy for child and family when behaviour is framed as being outside their control.

Second, medication should only be used if it is made explicit that it is for symptomatic relief, as an adjunct to other interventions. Potential harms must be openly discussed.

While not apparently a life-threatening drug, methylphenidate slows growth, disrupts sleep and, as the NSWPIC study shows, has an association with dangerous intoxication in suicidal or recreational use, in one’s self and others. And we still don’t know what long-term impact it has on the growing brain.

All of this would be acceptable if we weren’t lacking evidence to believe that medicating ADHD has a clinically positive impact on the associated significant risks – school failure, offending and drug misuse.

As with all drug prescribing, the prescriber, in consultation with the family, needs to weigh up potential benefits against potential harms.

In doing so, the prescriber needs to take account of the fact that apparent efficacy will be exaggerated by factors such as selective reporting and publication bias, and that harms will be underreported due to poor pharmacovigilance. 

Most often, the equation will not favour prescribing.

Professor Jon Jureidini is a child psychiatrist at the Women's and Children's Hospital, Adelaide, where he works in consultation-liaison psychiatry. He is professor in the disciplines of psychiatry and paediatrics at the University of Adelaide, where he leads the Robinson Research Institute's Critical and Ethical Mental Health (CEMH) research group and the Paediatric Mental Health Training Unit (PMHTU).