Risperidone redefined: A three-decade odyssey of broadening indications and evolving formulations

Risperidone, one of the most widely prescribed second-generation antipsychotics globally, is distinguished by its broad therapeutic utility and adaptable formulation strategies. It was the second atypical antipsychotic introduced after clozapine and its pharmacological profile was characterized by potent antagonism of dopamine D2 and serotonin 5HT2A receptors. It provided more effective management of positive, negative, and mood symptoms across psychiatric disorders while minimizing extrapyramidal side effects compared to first-generation agents. Since its introduction, risperidone's indications have expanded significantly to encompass schizophrenia, bipolar I disorder, and autism-related irritability across diverse age groups from children aged five years to older adults. This therapeutic breadth is matched by remarkable formulation versatility, beginning with oral tablets and liquid syrup, progressing to intramuscular depot injections, and most recently culminating in subcutaneous extended-release formulations approved in 2018, 2023, and 2025. These innovations address critical challenges in psychiatric care, particularly medication adherence, by offering flexible dosing intervals and eliminating the need for oral supplementation in newer formulations. This article provides a comprehensive review of risperidone's basic pharmacology, its evolving landscape of Food and Drug Administration-approved and off-label indications, the transformative journey from oral to long-acting injectable formulations, and the complex interplay among drug attitudes, patient perceptions, and treatment acceptance.