One in Four Anxiety Patients Also Had ADHD, a Clinic Found

What one clinic counted

The expected figure was 9.5 percent. That is the rate of ADHD among people with an anxiety disorder in the US National Comorbidity Survey Replication, the large population survey the authors take as their comparison. In a specialist anxiety clinic in Hamilton, Ontario, the figure reached 27.9 percent.

The counting was done by Michael Van Ameringen, Catherine Mancini, William Simpson and Beth Patterson, of the Department of Psychiatry and Behavioural Neurosciences at McMaster University, and reported in the journal CNS Neuroscience and Therapeutics in 2011. They took 129 consecutive admissions to the Anxiety Disorders Clinic at McMaster University Medical Centre and put every one of them through a structured diagnostic interview, a scripted set of questions that yields a diagnosis by fixed criteria rather than by clinical impression. Thirty-six of the 129 met criteria for adult ADHD. On a self-report questionnaire completed by 118 of them, the proportion was 31.4 percent.

These were established patients of an anxiety service, average age 33, roughly two thirds of them women. More than three quarters had already been treated with an antidepressant, and their clinician-rated severity at intake averaged 4.6 on a seven-point scale, which is moderate to marked illness.

Of the 36 adults who met criteria, 36.1 percent had been diagnosed with ADHD as children. Fewer had ever been treated for it, 16.7 percent at some point in their lives, and 2.8 percent at the time of the study. The remainder reached a sub-specialty clinic in their thirties with the attention question either never formally asked or answered another way.

The two groups were otherwise hard to tell apart. Patients with ADHD carried the same average number of lifetime diagnoses as those without, 3.2, and their clinician-rated severity was higher only slightly and not significantly. Where they did differ was in the texture of the anxiety itself: obsessive compulsive symptoms were substantially more severe, worry scores were higher, and depression had begun earlier in life. Those particular comparisons were run in a small, mostly female sample without correction for multiple testing, which makes them provisional, and the clinic is a tertiary referral centre where several diagnoses in one patient is the norm rather than a surprise. The 27.9 percent survives all of that. More than one patient in four in an anxiety clinic met criteria for a disorder of attention.

What it means for you and your child

This was an adult sample, and the paper says nothing directly about children. Carrying it across to a nine-year-old is an inference, and it should be held as one.

The study cannot speak to which condition came first, and the authors are explicit that the long-run relationship between the two is poorly understood, to the point that it is still unsettled whether anxiety worsens ADHD or shields a person from some of its consequences. Nobody should tell a parent that unrecognised attention difficulties produced their child’s worry, and this design does not permit it.

The clinic’s procedure is where the value lies. When a room already has an explanation for a child’s distress, the questions tend to stop. Worry accounts for the stomach aches and the hour it takes to fall asleep, the referral is written for anxiety, and attention is never examined on its own terms because nothing appears to be left over. In a clinic that put the attention question to every patient anyway, the yield was nearly three times the population figure.

Most of these patients had already had antidepressant treatment and were still moderately to markedly unwell when they were assessed. The study cannot test whether their attention difficulties explain that incomplete response, though it does show that a treated anxiety diagnosis and an unidentified attention disorder can occupy the same person for years without either being noticed by the other.

For a parent, that converts into a question rather than a course of action. An anxiety diagnosis describes what is most visible; whether anything else is present remains open. Attention can be assessed in its own right, with history from school and from home, rather than inferred from how distracted an anxious child appears.

Anxiety is the diagnosis the referral was written for. Whether attention has been examined separately, and on what evidence, is a different question, and it is yours to ask.