Anxiety Disorders and ADHD: Comorbidity the Rule, Not the Exception
Anxiety Disorders and ADHD: Comorbidity the Rule, Not the Exception
If you work in an anxiety disorder clinic or adult outpatient psychiatric clinic, you probably see a higher prevalence of patients with ADHD than you would in the general population.
Speaking during the Scientific and Clinical Report Session on attention spectrum disorders, Michael Van Ameringen, MD, FRCPC, Co-Director of the Anxiety Disorders Clinic at McMaster University Medical Center in Canada and Associate Professor in the Department of Psychiatry and Behavioral Neuroscience at McMaster University, summarized some of the medical literature on anxiety and ADHD prevalence.
He then described a study of 264 consecutive patients referred to the Anxiety Disorders Clinic in Hamilton, Canada. The patients completed the Adult ADHD self-report scale and were assessed with the Structured Clinical Interview for DSM-IV (SCID-I) and the ADHD module of the Mini International Neuropsychiatric Interview (MINI).
Of the patients referred for anxiety, the prevalence of lifetime ADHD was 37.5% (48.5% male, 51.5% female, p<0.05). “The prevalence of lifetime ADHD was higher in our anxiety disorders clinic than that found in the general population,” he concluded.
Among those with ADHD, comorbidity was the rule rather than the exception. ADHD was significantly associated with a primary diagnosis of impulse control disorder and bipolar disorder and most commonly associated with social phobia (57.6%, NS) and major depressive disorder (56.6%, NS).
Despite meeting DSM-IV criteria for lifetime ADHD, Van Ameringen noted that most patients in the study had never been given a diagnosis or treatment. Seventy-six percent (75/99) of those diagnosed with adult ADHD on the MINI had never received a prior diagnosis and only 17.2% had received ADHD treatment before the study.
When asked which disorder should be treated first when a patient has both ADHD and anxiety, Van Ameringen responded: “I would treat the most impairing condition first.”
Another study, this one conducted by Robert Kayser, MD, Staff Psychiatrist for the US Department of Veterans Affairs, examined the prevalence of ADHD and comorbid psychiatric disorders among patients at an outpatient clinic in Tucson, Arizona.
The prevalence of ADHD in the general adult population, he said, is estimated at 4.4%, but the prevalence of ADHD in adult outpatient psychiatric clinics is substantially higher—ranging from 17% to 22%.
Kayser’s recent study sought to determine the prevalence of ADHD among veterans referred by their primary care physicians for psychiatric evaluation in the mental health section of a community-based outpatient clinic as well as to determine the prevalence and types of comorbid psychiatric disorders in these patients with ADHD.
Among the 674 patients (629 males, 45 females) that Kayser personally evaluated between May, 2007 and December, 2010, 23.4% (158/674) had ADHD (22.4% males, 37.8% females).
Among the patients with ADHD, 93% had two or more comorbid psychiatric disorders, including major depression, dysthymic disorder, bipolar disorder, PTSD, panic disorder, and GAD. Forty-one percent (66/158) of those with ADHD were experiencing insomnia and 27.8% (44/158) had sleep apnea.
My “findings suggest the diagnosis of ADHD may be underrepresented among veterans in outpatient mental health clinics,” he wrote in his presentation summary. “This [finding] could have important prognostic and treatment implications.” He recommended that all veterans seen in mental health clinics be evaluated for ADHD.
Barriers to diagnosing ADHD in veterans, he said, include denial, an inability to recall childhood behaviors before the age of 7, concern about adversely affecting disability claims for PTSD, and lack of knowledge about adult ADHD and about use of stimulants.
Physician resistance is also an issue, he added, due to the lack of data and training in the diagnosis and treatment of adult ADHD, concern about the use of stimulant medications, restrictive formularies, lack of diagnostic clarity from overlapping symptoms, and the high rate of medical complexity and psychiatric comorbidity among patients with ADHD.
There is great resistance to acknowledging the presence of ADHD in adults. One has to question whatis this about. The argument below that that stimulants cause anxiety is an assumption. Frequently patients with ADHD will say stimulants have a calming effect. SSRI's cause anxiety , they have black box warnings, yet we use them all the time to treat Anxiety Disorders. The response one often hears from psychiatrists in off the record comments, the patient is drug seeking; which is an assumption. Perhaps when we speak discrimination against those individuals with mental illness, we should not exclude ourselves? One thing psychiatrists forget, which I imagine feeds some of the anti- psychiatry rhetoric, is that we are just as human as our patients. It is naive to think we do not operate in the world with biases and prejudices.
OK. I think it's time we had a frank, honest discussion about the overdiagnosis of ADHD and the overprescribing of stimulants. In what I have seen in my practice, stimulants are given out much like Junior Mints with very little regard to either of the two (yes, remember, there's TWO...and I know there's been a lot of contradictory evidence about the cardiovascular stuff recently....but there's still that OTHER one...) black box warnings. I see them given (on a regular basis, I'm afraid) to people who suffer from psychosis, seizure disorders, and, in the most egregious case, to a patient with known methamphetamine dependence.
These are serious, powerful drugs with serious side effects. By the way, in any of the statistics above, did anyone think to wonder that anxiety is one of the most common side effects of stimulants? This leads to the other problem I see on a regular basis: the co-prescribing of benzodiazepines to those individuals on stimulants. In most cases, what does it serve us to give, basically, an upper AND a downer to the same individual...?
Ever wonder why there's such a shortage of stimulants? Have we stopped to ask ourselves if this is an iatrogenic problem? Maybe, just maybe, (gasp!) could we be overprescribing these medications?
Let's also consider the abuse potential of these medications (remember that pesky OTHER black box warning?). There is little, if any, regard given to the abuse potential from what I have witnessed. Have any of us reviewed the statistics of stimulants diversion/abuse recently? Have they increased or decreased over the last few years?
Let's have that sensible discussion about stimulant prescribing. And let's remember that what's best for our patients is not simply granting their every prescription wish.
Thanks.