Up to 80% of adults with attention-deficit/hyperactivity disorder (ADHD) have at least one coexisting psychiatric disorder, including mood and anxiety disorders, substance use disorders, and personality disorders. However, psychiatric comorbidities aren’t inevitable for adults with ADHD. Early recognition and treatment of the disorder—and its comorbidities—have the potential to “change the trajectory” of psychiatric morbidity later in life, according to the authors of a recent review article published in the journal BMC Psychiatry.
“In fact, treating ADHD has been shown to prevent worsening comorbidities with depression, bipolarity, anxiety, and substance use disorders,” the authors wrote.
Comorbidities and complex presentations
Despite the relatively high prevalence of ADHD in adults—an estimated 2.5%—the disorder often goes unrecognized when patients present to the clinic, wrote Martin Katzman, MD, and colleagues in their article. Dr. Katzman is Clinic Director and staff psychiatrist at the S.T.A.R.T. (Stress, Trauma, Anxiety, Rehabilitation and Treatment) Clinic for Mood and Anxiety Disorders, in Toronto, Canada.
One significant reason why ADHD in adults may go unrecognized is that it may be overshadowed by another disorder.
To that end, Dr. Katzman and colleagues sought to identify a practical, “dimensional approach” to help clinicians diagnose ADHD in patients with complex presentations, as well as to improve patient outcomes in this under-treated population. (The dimensional approach, as opposed to a categorical approach, considers the disorder to occur along a spectrum of clinical presentations and severity.)
For their review, Dr. Katzman and colleagues included 150 articles from 1996 to 2016—particularly those that investigated ADHD in adult patients with comorbidities and complex presentations.
“ADHD [in adults] is associated with a higher risk of developing mood and anxiety disorders,” as well as functional and psychosocial impairments, the researchers wrote.
In fact, adults with ADHD are twice as likely to experience substance abuse or dependence, three times more likely to develop major depressive disorder, more than four times more likely to have a mood disorder, and six times more likely to develop persistent depressive disorder (dysthymia), the researchers reported.
ADHD also has a high prevalence of comorbidity with bipolar disorder, they noted, and several studies have indicated that comorbid ADHD hastens the onset of bipolar disorder at an earlier age.
Three key screening questions
“These comorbidities present important clinical challenges since their co-occurrence results in greater disease burden and more severe illness courses than ADHD or mood and anxiety disorders alone,” the authors wrote.
However, it can be difficult to distinguish whether a patient who presents with one of these common disorders also has comorbid ADHD. So, Dr. Katzman and colleagues provided three key questions that clinicians can ask to help identify red flags for ADHD diagnosis in complicated patients:
- “Have you had long-standing and consistent problems with attention and distractibility?”
- “Have your current complaints been present over the last 10 or 20 years?”
- “If I could see you in the classroom when you were a child, what would you be like?”
If the patient’s answers suggest a possible positive ADHD diagnosis, then the patient should be given an in-depth clinical interview using a validated screening instrument, the researchers advised. These include the Adult ADHD Self-Report Scale (ASRS), the Wender-Reimherr Adult Attention-Deficit Disorder Scale (WRAADDS), or the Conners Adult ADHD Rating Scales (CAARS).
If the diagnosis is positive, then the severity of functional impairment and quality of life can be assessed using the Weiss Functional Impairment Rating Scale (WFIRS) and the Adult ADHD Quality of Life Scale (AAQoL).
“Given that [ADHD] is often comorbid with other psychopathologies, including mood or anxiety disorders, substance use disorders, and personality disorders, adults presenting with symptoms of ADHD should be screened for these frequently comorbid conditions, and vice versa, in order to identify patients who could potentially benefit from optimal management of ADHD and its comorbidities,” the authors advised.
While the diagnosis of the patient with adult ADHD can be challenging, treatment of those who have comorbid conditions can also be complicated, the researchers noted.
“The best practice for comorbid ADHD and psychiatric disorders is the principle of treating the most serious or debilitating condition first and proceeding with treatment of subsequent residual symptoms in a stepwise manner,” they wrote. “If both conditions are equally debilitating, treatment for both conditions can be initiated in close succession, but preferably not at exactly the same time, so that side effects or lack of efficacy can be attributed to a single intervention.”
Interestingly, when the ADHD is effectively treated, the comorbid psychiatric symptoms may also show improvements, studies have found.
“Perhaps more exciting is the concept that early and optimal treatment of ADHD could potentially prevent the later development of psychiatric comorbidities,” Dr. Katzman and colleagues wrote.
For instance, a 10-year longitudinal follow-up study showed that male youths with ADHD who were treated with stimulants had a significantly lower risk of developing comorbid depressive and anxiety disorders as adults than those who were not treated. The treated patients were also significantly less likely to have impaired functional outcomes, the study found.
Another study found that adolescents with ADHD who were treated with stimulants had a significantly lower risk of cigarette smoking and development of substance use disorders after five years of follow-up.
“Taken together, these observations suggest that pharmacologic therapy for ADHD in young adults could change the trajectory of psychiatric morbidity in adulthood,” the authors wrote. “Such findings provide powerful support for the early and aggressive treatment of ADHD."
The review was funded by Janssen, Purdue, and Shire.