There is no doubt attention-deficit hyperactivity disorder (ADHD) in adults is a relatively new concept and as the evidence base emerges it is a good idea to critically appraise it. It has its problems being a ‘trait’ condition where the traits are distributed across the spectrum in the population. This poses a challenge to clinicians on where to set the bar for illness. One can argue to what extent this process is influenced by societal values and expectations.

The dilemma of categorising a symptom present in continuum in the population into an illness and wellness dichotomy is not unique to ADHD or even to mental health. It resonates with issues faced in setting the bar for hypertension or hyperglycaemia.

Rather than getting into a critical analysis, Moncrieff & Timimi ^{Reference Moncrieff and Timimi1} seem to have approached the subject in a one-sided way that tends towards not accepting the condition exits rather than objectively weighing up-to-date evidence. For example, they state: ‘The evidence from randomised trials in adults and children therefore provides little basis for the sort of long-term drug treatment that is now being implemented for adults presenting with ADHD de novo, or for those with a continuation of a childhood presentation’. With regard to this statement, it is unclear who is recommending this.

The paper repeatedly quotes secondary research and uses qualitative remarks without systematically analysing data. Rather than looking into evidence base for current pharmacological treatment, the authors mention the National Institute for Health and Clinical Excellence guidance and focus on three randomised controlled trials quoted in that document. The recent Cochrane review on the matter found seven studies. ^{Reference Castells, Ramos-Quiroga, Bosch, Nogueira and Casas2}

The authors raise the issue of lack of genetic overlap between ADHD in children and adults referring to the European consensus statement on diagnosis and treatment of adult ADHD. ^{Reference Kooij, Bejerot, Blackwell, Caci, Casas-Brugue and Carpentier3} The study does mention that ‘to date several publications highlight potential associations with ADHD in adults, some but not all of which are shared with genetic association findings in children’, which is again a conclusion they draw from five other pieces of research. This information gets subtly presented in the paper as: there are ‘some’ similar genes between adult and child ADHD but ‘many are different’. Further, the authors state that ‘there have been many challenges to the validity of the childhood disorder’. They support this statement with three references, two of which are their own publications.

The debate to be had in the clinical world of adult ADHD in the UK is the issue of false positives. Due to the relative lack of stigma of the condition (which is not necessarily a bad thing!) and the issue of diagnostic overlap (particularly with emotionally unstable personality disorders), front-line adult clinicians face a major challenge. Emotional instability is increasingly recognised in adults with ADHD. ^{Reference Asherson, Chen, Craddock and Taylor4}

With these commonalities in impulsivity and emotional dysregulation the difference between ADHD and emotionally unstable or borderline personality disorder gets blurred in adults (particularly with inclusion of attenuated varieties in DSM-IV) and hinge almost exclusively on ‘inattentiveness’. In my opinion, the authors let us down in not exploring in depth these and other real diagnostic and prescribing challenges surrounding adult ADHD.