Methylphenidate treatment of adult male prison inmates with attention-deficit hyperactivity disorder: randomised

inherited and disabling developmental disorder with early onset. Symptoms of ADHD often persist into adulthood. A recent meta-analysis of population-based studies across several countries estimated the pooled prevalence of adult ADHD to be 2.5% (95% CI 2.1–3.1). However, most of the populations in these studies were unbalanced with regard to gender and age, and applied different tools to diagnose ADHD according to DSM-IV. Therefore, the reported prevalence rates may not reflect the general population across these countries. Attention-deficit hyperactivity disorder is associated with pervasive cognitive, emotional and functional impairments that affect various aspects of life, including educational, occupational and social performance. In addition, nearly 80% of adults with ADHD present with at least one comorbid disorder, particularly anxiety disorders, affective disorders, substance use disorder and antisocial personality disorder. Both substance use disorder and antisocial personality disorder increase the risk for delinquency, and approximately 25–45% of adult prison inmates are estimated to have ADHD. Inmates with ADHD have an increased incidence of behavioural problems and comorbid psychiatric disorders, including substance use disorder and personality disorder, compared with other inmates. According to UK guidelines issued by the National Institute for Health and Clinical Excellence (NICE), drugs are the first-line treatment for ADHD in adults with moderate or severe levels of impairment, and methylphenidate is the drug of first choice. Clinical trials evaluating methylphenidate and other stimulants display short-term efficacy in both children and adults with ADHD. These trials have typically excluded participants with comorbid disorders. The small number of studies evaluating methylphenidate for participants with ADHD and comorbid substance use disorder has not been able to establish efficacy against ADHD. The long-term effectiveness, safety and tolerability of methylphenidate is not well understood as there have been few long-time follow-up studies. Despite the high prevalence of ADHD in prison inmates, pharmacological treatment has not been evaluated in this group. This is likely due to concerns about safety and misuse of the drug therapies by this patient population, and the challenge of conducting pharmacological trials in prison settings. The purpose of the present study was to evaluate the efficacy, long-term effectiveness, safety and tolerability of osmotic-release oral system (OROS) methylphenidate in adult long-term prison inmates with ADHD and comorbid disorders. The OROS methylphenidate was delivered at a daily dose of 72mg compared with placebo over a 5-week period, followed by an open-label extension with OROS methylphenidate delivered at a flexible dosage of up to 1.3mg/kg daily over a 47-week period.