Mediating Effect of Depressive Symptoms on the Relationship between Adult Attention Deficit Hyperactivity Disorder and Quality of Life

OBJECTIVE The aim of this study was to investigate whether depressive symptoms affect the relationship between adult attention deficit hyperactivity disorder (ADHD) and the quality of life (QOL) in Korean soldiers. METHODS We evaluated past and present symptoms of adult ADHD (the Korean Adult Attention-Deficit/Hyperactivity Disorder Scale and the Wender Utah Rating Scale), depression (the Center for Epidemiological Studies Depression Scale) and QOL (the Korean version of the SmithKline Beecham 'Quality of Life' scale) in 131 soldiers during mental health screenings performed by a local mental health center. A structured equation model using AMOS 19.0 was used to evaluate the mediating effect of depression. RESULTS In our first model (without depressive symptoms), adult ADHD significantly affected QOL (standardized regression weight=-0.51, p<0.01). After depressive symptoms were added to this model, the direct effect of adult ADHD on QOL was not significant (standardized regression weight=0.10, p=0.43). Regarding the indirect effect, adult ADHD significantly affected depression (standardized regression weight=0.78, p<0.01), and depression also affected QOL (standardized regression weight=-0.79, p<0.01). CONCLUSION Through structural equation modeling, the complete mediation model for the influence of depressive symptoms on ADHD and QOL was confirmed. These findings indicated that it might be important to consider comorbidities, such as depression, when adult ADHD is being evaluated.