© 2019 Hong Kong College of Psychiatrists. CC BY-NC-ND 4.0 East Asian Arch Psychiatry 2019;29:118-23 | https://doi.org/10.12809/eaap1851 Original Article 118 Adult Attention Defcit Hyperactivity Disorder in a Malaysian Forensic Mental Hospital: a Cross-sectional Study LSC Woon, H Zakaria Abstract Objective: To determine the prevalence of adult attention defcit hyperactivity disorder (ADHD) and comorbid mental disorders in a Malaysian forensic mental hospital. Methods: All adult patients admitted to the forensic wards who were able to understand Malay or English language and give written informed consent were included. Participants were assessed using the Conners Adult Attention-Defcit Diagnostic Interview for DSM-IV (for presence of adult ADHD and a history of childhood ADHD) and the Mini International Neuropsychiatric Interview (for psychiatric comorbidities). Sociodemographic and offence-related data were also collected. Results: Of 199 patients admitted, 120 were included for analysis. The mean age of participants was 36.3 years. 94.2% were men. 81.7% were single, divorced, or separated. 25% had a history of childhood ADHD. The prevalence of adult ADHD was 15.8%. The persistence rate was 63%. Among the 19 participants with adult ADHD, the most common psychiatric comorbidities were substance dependence (68.4%), lifetime depression (63.2%), and generalised anxiety disorder (47.4%). Compared with participants without ADHD, participants with adult ADHD were less likely to be married (0% vs 21.8%, p = 0.022) and more likely to have alcohol abuse (15.8% vs 2%, p = 0.028), lifetime manic/hypomanic episodes (42.1% vs 7.9%, p = 0.001), and generalised anxiety disorder (47.4% vs 19.8%, p = 0.017), and were of younger age at frst offence (21.8 years vs 26.9 years, p = 0.021). Conclusions: Adult ADHD is common in a Malaysian forensic mental hospital and is associated with unmarried status, alcohol abuse, lifetime manic/hypomanic episodes, generalised anxiety disorder, and younger age at frst offence. Key words: Attention defcit disorder with hyperactivity; Comorbidity; Forensic psychiatry; Hospitals, psychiatric; Prevalence Luke Sy-Cherng Woon, MD, DrPsych, Department of Psychiatry, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia Hazli Zakaria, MBBS, DrPsych, Department of Psychiatry, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia Address for correspondence: Dr Luke Sy-Cherng Woon, Department of Psychiatry, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia Email: lukewoon@gmail.com Submitted: 18 May 2018; Accepted: 12 October 2018 Introduction Attention defcit hyperactivity disorder (ADHD) is characterised by high levels of hyperactivity, impulsivity, and inattention since early childhood. The prevalence of childhood ADHD is estimated to be 4.0% to 8.0%. 1 In 15% of cases, the condition persists to age 25 years, and further 50% of cases were in partial remission. 2 The pooled prevalence of adult ADHD in meta-analyses has been 2.5% to 5.0%. 3,4 Childhood predictors of adult ADHD include treatment for ADHD and combined subtype of childhood ADHD, symptom severity, comorbidity with conduct and mood and anxiety disorders, psychosocial adversity, parental psychopathology, and family history of ADHD. 5,6 Other risk factors are male sex, low educational level, unemployment, and unmarried status. 7,8 The lifetime prevalence of psychiatric disorders is signifcantly higher in adults with ADHD than in the general population. 9 80% of adult ADHD cases have comorbidities. 10 Adult ADHD is associated with 5.4 times increased risk of bipolar disorder, 7 and 65% of adults with ADHD have major depression. 9 Adults with ADHD have 7.5 times higher odds of having any anxiety disorders and 3.8 times higher odds for all types of substance use disorder. 7 The prevalence of ADHD is 33% to 65% among individuals with cluster B personality disorders, and comorbidity of ADHD and antisocial personality disorder is common in the forensic population. 11 In two meta-analyses, the prevalence of ADHD in prison populations was estimated to be 25.5% and 26.2%. 12,13 In the Forensic Mental Health Services of the United Kingdom, 33% of patients with personality disorders were positive for ADHD. 14 Prisoners with ADHD involve in more aggressive incidents and have signifcantly younger onset of offending and higher rate of recidivism. 15 To the best of our knowledge, no study on adult