Schizophrenia-spectrum patients treated with long-acting injectable risperidone in real-life clinical settings: functional recovery in remitted versus stable, non-remitted patients (the EVeREST prospective observational cohort study).

BACKGROUND: Previous studies showed functional improvement in stable patients with schizophrenia treated with risperidone long-acting injection (LAI). We therefore re-investigated functional improvement with risperidone LAI in remitted patients, in comparison with stable patients. The study was conducted in real-life conditions because of the high heterogeneity of the patients' situations. METHOD: This was a multi-centre, prospective observational cohort study involving adult schizophrenia-spectrum chronic patients who were previously treated with risperidone LAI for 6 months. Remission was evaluated using the consensus criteria proposed by the Remission in Schizophrenia Working Group (RSWG). The primary endpoint was global functioning (assessed with the Global Assessment of Functioning scale, GAF) after one year of treatment. Social functioning was a secondary outcome. RESULTS: The analysis included 1490 patients. Attrition rate was 9.1 % at the end of the study. 27.7 % of patients were in remission after one year of risperidone LAI treatment. The mean GAF rating score (62.5 ± 1.5) was higher than the cut-off previously used to identify patients with satisfactory functioning (60) and significantly higher than the mean GAF score in stable, non-remitted patients (48.3, p < 0.001). Social functioning was also high in remitted patients (21.0 ± 3.6 vs. 17.2 ± 3.7 in non-remitted patients, p < 0.001). CONCLUSION: The results clearly show that after one year of treatment with risperidone LAI, RSWG-remitted patients have a high level of global functioning, which is significantly higher than in stable, non-remitted patients. Social functioning was also higher in remitted patients as compared with stable, non-remitted patients.

GLP-1 and GIP receptors signal through distinct ß-arrestin 2-dependent pathways to regulate pancreatic ß cell function.

Glucagon-like peptide 1 (GLP-1R) and glucose-dependent insulinotropic polypeptide (GIPR) receptors are G-protein-coupled receptors involved in glucose homeostasis. Diabetogenic conditions decrease ß-arrestin 2 (ARRB2) levels in human islets. In mouse ß cells, ARRB2 dampens insulin secretion by partially uncoupling cyclic AMP (cAMP)/protein kinase A (PKA) signaling at physiological doses of GLP-1, whereas at pharmacological doses, the activation of extracellular signal-related kinase (ERK)/cAMP-responsive element-binding protein (CREB) requires ARRB2. In contrast, GIP-potentiated insulin secretion needs ARRB2 in mouse and human islets. The GIPR-ARRB2 axis is not involved in cAMP/PKA or ERK signaling but does mediate GIP-induced F-actin depolymerization. Finally, the dual GLP-1/GIP agonist tirzepatide does not require ARRB2 for the potentiation of insulin secretion. Thus, ARRB2 plays distinct roles in regulating GLP-1R and GIPR signaling, and we highlight (1) its role in the physiological context and the possible functional consequences of its decreased expression in pathological situations such as diabetes and (2) the importance of assessing the signaling pathways engaged by the agonists (biased/dual) for therapeutic purposes.