Switching from risperidone to paliperidone palmitate in schizophrenia: Changes in social functioning and cognitive performance.

BACKGROUND: Previous studies suggest that paliperidone might show a better profile for social functioning and cognitive abilities than risperidone. We aimed to study whether switching from risperidone to paliperidone palmitate (PP) is associated with improved cognitive abilities at 3 or 6 months after the switch. METHODS: Thirty-eight patients with a DSM-IV diagnosis of schizophrenia were studied. All patients were treated with oral risperidone or risperidone long-acting injection (RLAI) and had an indication to be switched to PP by their psychiatrists. Statistical analyses were conducted in a final sample of 27 patients who completed the follow-up visits. Three assessments were completed: 1) baseline (preswitch), 2) 3 months postswitch, and 3) 6 months postswitch. Social functioning at each visit was assessed with the Personal and Social Performance Scale. Cognitive assessment was conducted at each visit with the MATRICS Consensus Cognitive Battery. Statistical analyses were performed with R. Linear mixed models were used to explore longitudinal changes in social functioning and cognitive outcomes. RESULTS: PSP scores significantly improved over time after the switch from risperidone to PP. A sensitivity analysis found a significant negative interaction between time and PP maintenance doses (greater improvement in those patients receiving lower doses when compared to higher doses). Regarding longitudinal changes in cognitive functioning, patients improved in 6 out of 10 cognitive tasks involving processing speed, working memory, visual memory, reasoning and problem solving, and attention and vigilance. CONCLUSIONS: Our study suggests that switching from risperidone to PP in patients with schizophrenia is associated with an improvement in social functioning and cognitive performance.

A pharmacogenetic intervention for the improvement of the safety profile of antipsychotic treatments.

Antipsychotic drugs fail to achieve adequate response in 30-50% of treated patients and about 50% of them develop severe and lasting side effects. Treatment failure results in poorer prognosis with devastating repercussions for the patients, carers and broader society. Our study evaluated the clinical benefits of a pharmacogenetic intervention for the personalisation of antipsychotic treatment. Pharmacogenetic information in key CYP polymorphisms was used to adjust clinical doses in a group of patients who started or switched treatment with antipsychotic drugs (PharmG+, N = 123), and their results were compared with those of a group of patients treated following existing clinical guides (PharmG-, N = 167). There was no evidence of significant differences in side effects between the two arms. Although patients who had their antipsychotic dose adjusted according to CYPs polymorphisms (PharmG+) had a bigger reduction in side effects than those treated as usual (PharmG-), the difference was not statistically significant (p > 0.05 for all comparisons). However, PharmG+ patients treated with CYP2D6 substrates that were carriers of CYP2D6 UMs or PMs variants showed a significantly higher improvement in global, psychic and other UKU side effects than PharmG- patients (p = 0.02, p = 0.05 and p = 0.01, respectively). PharmG+ clozapine treated patients with CYP1A2 or CYP2C19 UM and PMs variants also showed higher reductions in UKU scores than PharmG- clozapine patients in general. However, those differences were not statistically significant. Pharmacogenetic interventions may improve the safety of antipsychotic treatments by reducing associated side effects. This intervention may be particularly useful when considering treatment with antipsychotics with one major metabolic pathway, and therefore more susceptible to be affected by functional variants of CYP enzymes.

Hypothalamic-pituitary-adrenal system, neurotrophic factors and clozapine response: association with FKBP5 and NTRK2 genes.

Clozapine is an atypical antipsychotic drug known as being more effective compared with traditional antipsychotics for patients with poor response or resistance to treatment. It has been demonstrated that clozapine modulates hypothalamic-pituitary-adrenal activity and affects central brain-derived neurotrophic factor levels, which could explain part of its therapeutic efficacy. In this study, we investigated the role of genes related to the hypothalamic-pituitary-adrenal axis (FKBP5 and NR3C1) and neurotrophic factors (BDNF and NTRK2) in clinical response to clozapine in 591 schizophrenia patients. We found significant allelic and genotype associations between FKBP5-rs1360780, NTRK2-rs1778929 and NTRK2-rs10465180 polymorphisms and clozapine response. The haplotypes composed of rs1360780-rs3777747-rs17542466-rs2766533 (FKBP5) and rs1619120-rs1778929-rs10465180 (NTRK2) were also nominally significant. Our results suggest that genetic variability in FKBP5 and NTRK2 genes may partially explain clinical response to clozapine. Further studies are needed to clarify the involvement of these genes in clinical response to atypical antipsychotics.