Long-acting risperidone improves negative symptoms in stable psychotic patients

The aim of this paper was to evaluate the efficacy of risperidone long-acting injectable (RLAI) for reducing negative symptoms of schizophrenia in patients with predominantly negative symptoms at baseline. A subanalysis was performed on data from the 6-month, open-label Switch to Risperidone Microspheres trial. Patients with Positive and Negative Syndrome Scale (PANSS) negative subscale score ≥21, which was higher than their PANSS positive subscale score, were included in this subanalysis. Improvement in negative symptoms was measured by assessing change in the PANSS negative subscale and a negative factor score. Additional outcome variables included measures in general functioning, quality of life and patient satisfaction. A total of 842 patients were eligible for inclusion in this subanalysis. Six months of treatment was completed by 631 (74.9%) patients. Forty-three (5.1%) patients discontinued treatment due to an adverse event. Negative symptoms were significantly reduced by 6.1 ± 6.3 points for the PANSS negative score and 6.1 ± 6.4 points for the negative factor score (P < 0.0001 for both). Significant improvements were also noted for total PANSS and other PANSS subscale scores, general functioning, quality of life and patient satisfaction (P < 0.0001). The most common treatment-emergent adverse events (>5%) were: anxiety (6.8% of patients), exacerbation of disease (6.2%) and insomnia (5.7%). Overall, RLAI was well tolerated and associated with significant reductions in movement disorder severity. The treatment resulted in a significant improvement in negative symptom severity and was well tolerated in patients with predominantly negative symptoms, who switched from a stable antipsychotic regimen.