RESUMO
BACKGROUND: D-serine and the D-amino acid oxidase (DAO) enzyme, which breaks down d-amino acids, may be involved in the pathophysiology of schizophrenia by affecting the N-methyl-D-aspartate (NMDA) receptor. The exact role of D-serine and DAO, as well as the consequences of increased DAO activity in patients with schizophrenia, remain unclear. We aimed to investigate D-serine and DAO levels in patients with first-episode schizophrenia spectrum disorders before treatment and after six months of treatment. METHOD: Comparisons for the serum levels of D-serine and DAO were made between 81 healthy controls and 89 patients with first-episode schizophrenia spectrum disorders without a history of treatment. Further comparisons were made after 6 months for changes in these levels in the 41 patients in follow-up. The Positive and Negative Syndrome Scale (PANNS), Calgary Scale for Depression in Schizophrenia (CDSS), Montreal Cognitive Assessment Scale (MoCA), Global Assessment Scale (GAS), and Clinical Global Impression Scale (CGI) were used to evaluate the symptom severity and functionality. Secondary results included comparisons related to antipsychotic equivalent doses. RESULTS: Before treatment, patients had significantly lower levels of D-serine, DAO, and D-serine/DAO ratio compared to healthy individuals (p < 0.001; p < 0.001; p = 0.004). DAO and D-serine levels of the patients were higher after six months of treatment (p = 0.025; p = 0.001). There was correlation of DAO levels with antipsychotic dosage and with PANSS negative and total subscale scores (rho = 0.421, p = 0.01; rho = 0.280, p = 0.008; rho = 0.371, p = 0.000). No correlation was found between serum D-serine level, DAO level, and the D-serine/DAO ratio with cognitive function. CONCLUSIONS: The results suggest that D-serine and DAO may play a role that is sensitive to treatment effects in schizophrenia spectrum disorders. To gain a more comprehensive understanding of the impact antipsychotic drugs have on NMDA receptor dysfunction, there is a requirement for studies that directly evaluates the activity of the DAO enzyme.
RESUMO
ABSTRACT: The stress coping strategies of patients with bipolar disorder (BD) may affect their suicide risk. We examined coping behaviors and impact of coping strategies and clinical characteristics on suicide attempts and lifetime suicidal ideation in patients with BD I, compared with a healthy control group. We recruited 185 euthymic patients with BD and 94 healthy controls. Participants completed the Coping Orientation to Problems Experienced Inventory. Suicide attempt prevalence in patients with BD was around 34%, and frequency of lifetime suicide ideation was around 60%. Binary logistic regression analysis revealed greater use of behavioral disengagement and religious coping strategies among patients with BD, compared with controls. Patients with previous suicide attempts presented a more severe illness course, notably early onset, with more depressive and mixed episodes and a more dysfunctional coping style than nonsuicidal patients. Behavioral interventions can target avoidant coping behavior, such as denial, especially in patients with suicide attempts.
