This subgroup analysis of the 6-month, open-label Switch to Risperidone Microspheres (StoRMi) trial evaluated long-term safety and efficacy of a direct conversion to risperidone long-acting injectable (RLAI) in 52 elderly patients (> or =65 years) with psychosis stabilized on oral or depot antipsychotic. Study outcomes included adverse events, movement disorder severity, psychiatric symptoms, functional ability, quality of life and patient satisfaction. Change in the Positive and Negative Syndrome Scale at endpoint was the primary efficacy measure. The most common dosage of RLAI used at endpoint was 25 mg every 14 days (60%). The trial was completed by 81% of patients, with six patients discontinuing treatment due to an adverse event. Tolerability was good and most side effects were mild to moderate. Serious adverse events occurred in 11 patients. Two of these (suicidal attempt, n = 1; exacerbation of disease, n = 1) were considered possibly related to RLAI. Conversion to RLAI resulted in significant improvements in movement disorder severity, psychiatric symptoms, functional status and patient satisfaction. Mean PANSS total decreased by 15.8 at endpoint, with 23 patients (46.9%) experiencing a > or =20% improvement. This post-hoc analysis supports that RLAI is well tolerated and safe in elderly patients with psychotic illnesses switched from stable antipsychotic regimens, and suggests possible efficacy, although inferences are limited.