A prospective investigation of impacts of comorbid attention deficit hyperactivity disorder (ADHD) on clinical features and long-term treatment response in adult patients with obsessive-compulsive disorder (OCD).

BACKGROUND: A close association between obsessive-compulsive disorder (OCD) and attention-deficit/hyperactivity disorder (ADHD) in children and adolescents has been investigated in previous studies. However, few studies examined the relationship between lifetime comorbidity of ADHD and OCD in adults. Therefore, we sought to investigate the clinical and psychopathological features related to comorbid ADHD in Japanese adult patients with OCD. METHODS: We assessed lifetime comorbidity of ADHD in 93 adult Japanese patients with OCD. Additionally, we used the Japanese version of Conners' Adult ADHD Rating Scales to assess the characteristics and severity of ADHD in each participant. According to the results, we excluded OCD patients that did not have ADHD but who exhibited elevated levels of ADHD traits. We compared OCD patients with ADHD (ADHD+ group) and those without ADHD or its trait (ADHD- group) in terms of background profiles and clinical features, such as OCD symptomatology and psychometric test results. Additionally, the 6-month treatment outcome was compared prospectively between groups. RESULTS: Of the 93 OCD participants, the prevalence of lifetime comorbidity of ADHD was estimated as 16.1%. Compared with the ADHD- group, participants in the ADHD+ group had an earlier age of onset of OCD, higher frequencies of hoarding symptoms, higher levels of depressive and anxiety symptoms and lower quality of life, more elevated levels of impulsivity, and higher rates of substance or behavioral addiction and major depression. Finally, the mean improvement rate on the Yale-Brown Obsessive Compulsive Scale after 6 months of standardized OCD treatment in the ADHD+ group (16.1%) was significantly lower than that in the ADHD- group (44.6%). CONCLUSION: The lifetime comorbidity of ADHD is likely to exert a significant effect on clinical features and treatment outcome in adult patients with OCD. It is important to consider that underlying ADHD pathology may function as a facilitator for increased severity of global clinical features and treatment refractory conditions in OCD patients. Further studies are required to examine treatment strategies for such patients.

The cryo-EM structure of full-length RAD52 protein contains an undecameric ring.

The human RAD52 protein, which forms an oligomeric ring structure, is involved in DNA double-strand break repair. The N-terminal half of RAD52 is primarily responsible for self-oligomerisation and DNA binding. Crystallographic studies have revealed the detailed structure of the N-terminal half. However, only low-resolution structures have been reported for the full-length protein, and thus the structural role of the C-terminal half in self-oligomerisation has remained elusive. In this study, we determined the solution structure of the human RAD52 protein by cryo-electron microscopy (cryo-EM), at an average resolution of 3.5 Å. The structure revealed an undecameric ring that is nearly identical to the crystal structures of the N-terminal half. The cryo-EM map for the C-terminal half was poorly defined, indicating that the region is intrinsically disordered. The present cryo-EM structure provides important insights into the mechanistic roles played by the N-terminal and C-terminal halves of RAD52 during DNA double-strand break repair.