Comorbid Psychiatric Conditions Common for Adults With ADHD

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The most frequent psychiatric disorder that appeared in patients with ADHD was substance use disorder, followed by mood disorders, anxiety disorders, and personality disorders.

Adults with attention deficit/hyperactive disorder (ADHD) are more likely to have comorbid psychiatric conditions like mood and personality disorders than the general population.

A team, led by Won-Seok Choi, Department of Psychiatry, Hallym University Sacred Heart Hospital, identified the prevalence of comorbid psychiatric disorders in adult patients with ADHD compared to adults without ADHD.

The Unknown

It remains crucial to study comorbid psychiatric conditions for adult patients with ADHD because they might complicate the ADHD diagnosis and worsen the prognosis.

However, it is unknown what the overall prevalence of comorbid psychiatric conditions is for adult patients with ADHD because it could vary based on different diagnostic tools used and the characteristics of the target populations.

In addition, studies and data are more prevalence in the pediatric population compared to the adult population for ADHD.

Despite that fact, the comorbidity rate is higher in adult patients with ADHD, with as many as 80% of adults with ADHD reporting at least 1 comorbid psychiatric disorder.

In the systematic literature review, the investigators identified 32 studies between January 1, 1990 and August 1, 2022. Each study was classified according to the diagnosis of other psychiatric disorders in groups of adult patients with ADHD.

Patient Population

Of this group, 11 studies involved general populations, 18 included psychiatric populations, and 3 studies had incarcerated populations as its patient sample.

In addition, 12 diagnostic tools were used, including clinical diagnostic criteria like DSM or ICD. Mainly 5 diagnostic tools were used for the comorbid psychiatric disorder, with most used the Adult ADHD Self-Report Scale for the adult ADHD population.

Five studies also used ASRS alone to evaluate ADHD, while the Connor’s Adult ADHD Diagnostic Interview for DSM-IV and the Wender Utah Rating Scale also commonly used.

In the review, the investigators identified 19 studies looking at mood disorders, including depressive disorders and bipolar disorders.

Prevalence of Disease

The most frequent psychiatric disorder that appeared in patients with ADHD was substance use disorder (SUD). There was also a high prevalence of mood disorders, anxiety disorders, and personality disorders in this group.

“The prevalence of these four disorders was higher in the ADHD group, whether or not subjects were diagnosed with other psychiatric disorders,” the authors wrote.

The investigators also found diversity of ADHD diagnostic tools was found throughout the study, which could have affected the variability in the prevalence of comorbidities.

The prevalence of depressive disorders in adults with ADHD was between 8.6-55% compared to 1.2-12.5% for the non-ADHD group.

The non-ADHD group also had a prevalence of bipolar disorder of 0.2-3.6%, compared to 4.48-35.3% for the ADHD group.

However, the investigators did not observe any differences in the prevalence of mood disorders between ADHD and non-ADHD cohorts in the incarcerated population.

There was also 16 studies involving anxiety disorders, including obsessive-compulsive disorder, somatoform disorders, and trauma/stress-related disorders between the 2 groups.

The prevalence of any anxiety disorder in the non-ADHD group was estimated at between 0.5-9.5% compared to 4.3-47.1% for the ADHD group.

Finally, 22 studies had data on substance use disorders, including addiction to alcohol, opioids, stimulants, cannabis, anxiolytics, and nicotine, as well as gambling disorders.

The prevalence of substance use disorder was between 0-16.6% in the general population, compared to 2.3-41.2% in the ADHD population.

The investigators suggest the standardization of ADHD diagnostic tools in the future.

“In conclusion, our findings indicate a higher prevalence of comorbid psychiatric disorders in ADHD subjects compared to non-ADHD subjects, whether they were previously diagnosed with other psychiatric disorders or not,” the authors wrote. “Furthermore, our results suggest a complex association between the multiple comorbidities of ADHD. Given that ADHD is often unrecognized and under-diagnosed in adults, screening for ADHD might be beneficial for patients presenting multiple psychopathologies including substance abuse, mood disorders, and anxiety disorders.”

The study, “The prevalence of psychiatric comorbidities in adult ADHD compared with non-ADHD populations: A systematic literature review,” was published online in PLOS One.