The role of rumination and racing thoughts in co-occurrence of ADHD symptoms, depression and anxiety symptoms

Abstract

Objective: Higher rates of comorbidity for depressive disorders and anxiety disorders have been observed in adults with Attention-Deficit/Hyperactivity Disorder (ADHD), which result in a significantly poorer prognosis. Developing an understanding of why this comorbidity occurs may help identify modifiable factors and inform treatment approaches. However, there is limited research examining the mechanisms through which these symptoms co-occur. This study evaluated whether racing thoughts and rumination (which have been observed in adults with ADHD, depression and anxiety) mediate the relationship between inattentive and hyperactive/impulsive symptoms of ADHD and depression and anxiety symptoms in a general population sample. Method: Participants were 289 adults, aged 18–65 (M = 38.57; SD = 11.24; 64% female), who completed online self-report questionnaires assessing their symptoms of inattention and hyperactivity/impulsivity, racing thoughts, rumination, and depression and anxiety symptoms. Results: Racing thoughts significantly mediated the relationship between inattentive and hyperactive/impulsive symptoms of ADHD with depression and anxiety symptoms. Rumination significantly mediated the relationship between hyperactive/impulsive symptoms, but not inattentive symptoms, with depression and anxiety symptoms. Conclusion: Implications for future research and interventions are outlined in relation to the role racing thoughts and rumination may play in the association between ADHD symptoms and depression and anxiety symptoms.