Prevalence of attention‐deficit hyperactivity disorder in adult prisoners: An updated meta‐analysis

Abstract

BackgroundPrevious meta‐analyses may have overestimated the prevalence of attention‐deficit hyperactivity disorder (ADHD) in prisoners by including data from selected samples.AimsTo estimate the prevalence of ADHD in unselected samples of adults in prison and examine potential sources of heterogeneity by meta‐regression and subgroup analyses.MethodsWe assessed all studies included in a 2018 systematic review for eligibility and updated the literature search to include studies published up to September 2023.ResultsA total of 11 studies reporting robust diagnostic data on ADHD in 3919 unselected adults in prison were included. In meta‐regression, ADHD prevalence did not differ between men and women but it was significantly higher in studies using a two‐phase design. In random sampling studies, the pooled prevalence of ADHD was 8.3% (95% CI: 3.8–12.8) which was further halved after the removal of an outlier.ConclusionOne in 12 adults in prison have been diagnosed with ADHD. Our findings highlight the importance of using clear and consistent inclusion criteria in meta‐analyses of prevalence.

Meta‐analysis of the prevalence of attention‐deficit hyperactivity disorder in prison: A comment on Fazel and Favril (2024) and reanalysis of the data

“…Moreover, Fazel and Favril (2024) decided to only include randomly selected samples. However, this strategy led to the exclusion of some studies that invited all detained persons from a prison to participate, sometimes with a high response rate.…”

“…We would also like to draw attention to the exclusion criteria of the studies themselves. Some studies analysed in Baggio et al (2018) and in Fazel and Favril (2024) excluded participants with mental health problems or disruptive behaviour. While this is understandable, as it may be difficult to interview these detained persons, it could lead to an underestimation of the true prevalence of ADHD.…”

“…We also provide a reanalysis of our previous meta-analysis only including adult samples. Fazel and Favril (2024) sought to investigate the prevalence of ADHD in the 'general prison population' by conducting a reanalysis that excluded what they termed 'selected samples'. These excluded samples included participants selected based on self-reported ADHD scores, having a primary diagnosis of another psychiatric disorder, involved in violent offending or referred for psychiatric care.…”

“…We acknowledge the importance of sample selection, as an unrepresentative sampling may lead to a biased estimation of prevalence. For example, if participants were selected based on the presence of other psychiatric disorders or a positive ADHD screening test (what Fazel and Favril (2024) called a 'two-stage' approach), the prevalence of ADHD would probably be overestimated. However, we argue that the exclusion of samples on people with violent offending or referred to psychiatric care may lead to an underestimation of true prevalence.…”

“…In fact, ADHD is often associated with comorbid psychiatric disorders, particularly substance use disorders, mood disorders, anxiety disorders and personality disorders (Choi et al, 2022). In addition, these incarcerated individuals are part of the 'general prison population', and therefore the prevalence estimated by Fazel and Favril (2024) is not reflective of the whole prison population.…”