Attention-deficit/hyperactivity disorder and autism spectrum disorder in chronic pain: a study in Japanese pain centers.

Chronic pain is influenced by physical and psychosocial factors and associated with symptoms of attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD); however, the specific symptom dimension related to pain severity and the underlying psychosocial pathways remain unclear. This cross-sectional screening study included 958 adult patients with persistent chronic pain despite standard care at their initial visit to multidisciplinary pain centers (Japan). Screening positivity rates were 17.1% for ADHD and 4.4% for ASD. ADHD symptoms, but not ASD symptoms, were considerably associated with higher pain intensity and extremely severe pain [average numerical rating scale score: 9-10]. Among patients with extremely severe pain, 27.4% were screened positive for ADHD. Hierarchical logistic regression analyses revealed that the association between ADHD symptoms and extremely severe pain was attenuated after adjustment for anxiety/depression and pain catastrophizing. Path analyses further indicated that ADHD symptoms were indirectly associated with severe chronic pain through anxiety/depression alone or through anxiety/depression combined with pain catastrophizing. Thus, ADHD symptoms are more strongly associated with pain severity than ASD symptoms in patients with persistent chronic pain, and emotional and cognitive factors may play a key mediating role. Screening for ADHD symptoms is crucial for comprehensive management of severe chronic pain.