Risperidone long-acting in-situ microimplant following a brief oral risperidone lead-in in the acute inpatient management of manic episodes with psychotic symptoms in non-adherent patients with schizoaffective disorder: a retrospective, uncontrolled real-world study

Background Nonadherence is a major cause of relapse in patients with schizophrenia, schizoaffective disorder, or bipolar disorder who have achieved remission. However, it is also a significant challenge during manic episodes. Risperidone in-situ microimplant (ISM) releases the drug early and in a sustained manner once a month, eliminating the need for daily administration, which can be difficult during a manic episode. In this study, we described symptom trajectories and tolerability of a brief oral risperidone lead-in followed off-label initiation of risperidone ISM within multimodal inpatient care in nonadherent inpatients with schizoaffective disorder experiencing a manic episode with psychotic symptoms. Methods This retrospective, observational, single-centre study included 50 consecutive adults admitted after discontinuation/marked non-adherence and with prior response to risperidone who received ≥ 6 days of oral risperidone to confirm tolerability, then risperidone ISM (75 or 100 mg) and were followed for 6 weeks. Mania severity was assessed with the Young Mania Rating Scale (YMRS). Results Fifty patients were included; most received concomitant mood stabilisers and benzodiazepines. Median YMRS decreased from 32 at admission (Tx) to 26 at the first injection (T0, after the oral lead-in), 8 by day 8, and remained low at day 28 (5) and day 42 (6). Activation/behavioural items improved earlier, whereas psychotic thought content improved more gradually, predominantly between days 8 and 28. Side-effect burden at weeks 4 and 6 was minimal, and no discontinuations due to adverse events occurred. Conclusions In this exploratory uncontrolled cohort, an oral risperidone lead-in plus monthly risperidone ISM within multimodal inpatient care was associated with with rapid and sustained improvement in symptom trajectories and favourable short-term tolerability. Findings reflect multimodal inpatient care and cannot be attributed to ISM alone. Prospective, controlled studies are warranted.