In this case report we present the case of three sisters experiencing shared psychotic disorder (SPD), or folie à trois, characterized by the transmission of delusional beliefs within close familial relationships. The primary patient presented aggressive behaviors and paranoid delusions, leading to hospitalization, while the other two siblings displayed similar beliefs but with less severe symptoms. Treatment involved physical separation and pharmacological intervention, resulting in significant improvement, particularly in the induced siblings. The case underscores the importance of a comprehensive approach to managing SPD, combining pharmacotherapy and psychosocial interventions. Further research is needed to improve understanding and optimize treatment strategies for shared delusions. Documenting and sharing such cases can contribute to improved outcomes for patients and their families.