4.1 RELATIONSHIP BETWEEN ADHD AND PTSD: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract

PTSD is a disorder that occurs after a traumatic experience. Although exposure to trauma is common, few individuals exposed to trauma develop PTSD, suggesting that these individuals have predisposing risk factors. ADHD is one such possible risk factor. The goal of this study was to examine the relationship between ADHD and PTSD by conducting a systematic review and meta-analysis of the literature on the association between ADHD and PTSD. We hypothesized that the literature would show a robust and bidirectional association between ADHD and PTSD. We reviewed literature through PubMed and PsycINFO in the year 2014 utilizing the search (posttraumatic stress disorder OR PTSD) AND (ADHD OR attention deficit hyperactivity disorder OR ADD OR attention deficit disorder OR hyperkinetic syndrome OR minimal brain dysfunction). We included original human research in English that operationalized diagnoses of ADHD and PTSD, evaluated the relationship between the disorders, and included controls. We extracted sample size, age, diagnostic methods, design, referral status, control type, and number of subjects with and without ADHD and PTSD alone and combined. We computed meta-analyses for studies examining ADHD in PTSD and PTSD in ADHD using a random-effects model and meta-analytic regression. We assessed for heterogeneity and publication bias and adjusted for intrastudy clustering. We identified 402 articles; 29 met the criteria for inclusion (14 with adult subjects and 15 with child subjects). The relative risk (RR) for PTSD in individuals with ADHD was 2.9 (p < 0.0005). In samples using only normal controls, the RR was 3.7 (p = 0.001), and in samples using trauma-exposed controls, the RR was 1.6 (p = 0.003). The RR for ADHD in individuals with PTSD was 1.7 (p < 0.0005), and in samples using trauma-exposed controls, the RR was 2.1 (p < 0.0005). All 6 studies examining the temporality of each disorder found earlier ADHD onset than PTSD. All 6 studies examining the correlation between ADHD and PTSD symptoms found a positive and significant correlation. Results indicate a bidirectional association between ADHD and PTSD, suggesting clinical implications and highlighting the need for neurobiological research examining the mechanisms underlying this connection.