Alcohol misuse and insomnia were significantly correlated with attention-deficit/hyperactivity disorder (ADHD) symptom severity, according to results of a cross-sectional study published in Frontiers in Psychology. Among adults without a clinical diagnosis of ADHD, heavy alcohol use predicted more severe ADHD symptoms.
Researchers at the University of Bergen in Norway recruited patients with ADHD from a national registry of adults diagnosed between 1997 and 2005, as well as healthy controls randomly recruited from the Medical Birth Registry of Norway. Adults with an ADHD diagnosis (n=235) and controls (n=184) completed a questionnaire assessing insomnia, alcohol consumption, and current ADHD symptoms.
The researchers used the Bergen Insomnia Scale, Alcohol Use Disorders Identification Test (AUDIT), and Adult ADHD Self-Report Scale (ASRS) to capture symptoms. Patients with ADHD had the option to provide information on childhood ADHD and lifetime internalizing symptoms. Independent sample t-tests and Chi-square tests were used to capture differences between the groups. Linear regression analyses were performed with ASRS scores as the outcome variable.
The ADHD and control groups did not differ significantly with respect to gender or age. The majority of participants were women (ADHD group: 58.7%; control group: 62.0%), and mean age was 37.91±11.2 years in the ADHD group and 36.55±8.2 years in the control group.
Compared with the control group, a lower proportion of patients with ADHD had completed university (34.3% vs 77.8%; P <.001) or were currently employed (40.2% vs 88.4%; P <.001). The mean AUDIT sum score was significantly higher in the ADHD group vs controls (13.59 vs 12.32; P <.005), suggesting greater severity of alcohol consumption in patients with ADHD. Insomnia was also more frequent in the ADHD group (67.2% vs 28.8%; P <.001).
Among participants with insomnia, 46.9% of the ADHD group and 24.6% of the control group reported drinking at least 5-6 units of alcohol when drinking. Mean ASRS scores were 42.18±12.50 and 21.77±9.78 in the ADHD and control groups, respectively. Insomnia was associated with more severe ASRS scores in patients and controls. In regression analyses, the variance in adult ADHD symptoms among patients with ADHD was explained by insomnia and internalizing symptoms, but not alcohol consumption. In the control group, however, ADHD symptoms were significantly associated with alcohol use.
Study limitations included a reliance on self-report data; patients may have reported lower alcohol use due to bias.
Alcohol use may be associated with ADHD symptoms, even among adults without a clinical ADHD diagnosis. Additionally, insomnia was associated with increased alcohol consumption and more severe ADHD symptoms in both patients and controls. The researchers noted that their findings may “put a critical light on a categorical delineation between adults with a clinical ADHD diagnosis and controls.”
Lundervold AJ, Jensen DA, Haavik J. Insomnia, alcohol consumption and ADHD symptoms in adults [published online May 27, 2020]. Front Psychol. doi: 10.3389/fpsyg.2020.01150