A Cross-sectional Cohort Study of Prevalence, Co-Morbidities, and Correlates of Attention-deficit Hyperactivity Disorder among Adult Patients Admitted to the Li Ka Shing Psychiatric Outpatient Clinic, Hong Kong.

OBJECTIVE: To examine the prevalence, co-morbidities, and correlates of attention-deficit hyperactivity disorder (ADHD) among adult patients who attended the Li Ka Shing psychiatric outpatient clinic (LKSPC), Hong Kong.

METHODS: This study was a cross-sectional cohort study of patients consecutively referred to LKSPC over a 3-month period for evaluation of adult ADHD in 2 phases. In the screening phase, the Adult ADHD Self-Report Scale-v1.1 (ASRS-v1.1) Screener and Symptom Checklist and Sheehan Disability Scale (SDS) were used in the evaluation. In the interview phase, ADHD diagnosis was ascertained using the Diagnostic Interview for ADHD in Adults, version 2.0 (DIVA 2.0), with the DSM-5 criteria, in patients who exceeded the cut-off point of either the ASRS-v1.1 Screener or Symptom Checklist.

RESULTS: The study included 254 patients of whom 49 were diagnosed with ADHD. Patients with ADHD were aged 18 to 60 (mean, 40.1) years, and 63.3% were women. The estimated prevalence of ADHD in adult psychiatric patients, by sensitivity analysis, was 13% to 19.3% with a higher prevalence in men than women (24.7% vs. 17.1%). Adult ADHD was highly co-morbid with substance / alcohol use disorders and forensic record, and associated with functional impairment. In the ADHD combined presentation group, there was additional co-morbidities of bipolar disorder, active substance use and chronic alcohol use, and a higher associated risk of suicidal attempt.

CONCLUSIONS: Efforts are needed to increase the detection and treatment of adult ADHD that affects a relevant proportion of our adult psychiatric outpatient population, and was associated with adverse social outcomes and functional impairment.