“In general, it’s not been used as a primary outcome, because everyone is so focused on the core ADHD symptoms, but I think if you set up a study where it was the primary outcome, you’d expect to see very similar results.”

Turning to the reasons why emotional instability was dropped from the key domains of ADHD in the first place, Dr Asherson commented: “When the DSM came along, they started to view ADHD as more of a cognitive and educational model, and perhaps this executive function model became more prominent.”

“There was a group of people in the states in particular who felt it often reflect other conditions, like bipolar disorder, rather than perhaps a core feature of ADHD, but it seems the tide has very much turned, and so most of the experts in the field have come around to thinking, ‘Yeah, actually, it does seem to be part of ADHD,’ ” he added.

Dr Asherson noted that the DSM-5 says that emotional lability is a core feature of ADHD and that, although it should not be used in the differential diagnosis, it can support the diagnosis.

“But I think, as a clinician, and particularly in adult psychiatry, where people are less familiar with ADHD, if they see mood instability, they’ll often be thinking bipolar, depression, or personality disorder, and they forget that ADHD can also cause it,” he said.

Need for Biological Markers

The problems with, and new developments in, the diagnosis of ADHD was the theme of the session. Chair Andreas Warnke, MD, PhD, professor emeritus of child and adolescent psychiatry at the University of Würzburg, Germany, explained why this is such an important consideration.

Dr Warnke told Medscape Medical News that information given by patients and parents is the basis of the diagnosis of ADHD.

“The critique on the diagnosis is that’s very subjective, it’s age dependent, and there are only some of the symptoms, [and] of course, there is a dependence on the task you have to solve,” he said, adding: “If you can run all the day, it’s not a problem, but if you have to sit still, then it’s a problem.”

Dr Warnke noted that the result is that there are large discrepancies in the recorded prevalence of ADHD both between and within countries, including the Unite States.

The answer, he said, is that biological markers are needed to help definitively diagnose ADHD: “We need more and more markers that [a patient] really has this diagnosis, because we give medication, and in this case, it’s very important that we don’t treat the wrong people.”

5th World Congress on Attention Deficit Hyperactivity Disorder (ADHD). Abstract PL-1-002. Presented May 29, 2015.

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Liam Davenport