Agomelatine-Induced Subjective Double Delusion in Adolescent Bipolar Disorder

Delusional misidentification syndromes are rare psychiatric conditions, and subjective double delusion is particularly uncommon in adolescents. Agomelatine, an antidepressant with melatonergic and serotonergic properties, has limited evidence in pediatric populations and may trigger mood instability in vulnerable individuals.

We report the case of a 17-year-old male with a history of depressive symptoms who developed a manic episode with psychotic features shortly after initiating agomelatine. The clinical picture was dominated by a subjective double delusion, in which the patient believed an identical double existed and conspired against him. Following discontinuation of agomelatine and initiation of olanzapine, significant clinical improvement was observed within three weeks. Symptom reduction was confirmed with standardized rating scales.

This case highlights the importance of cautious antidepressant use in adolescents at risk for bipolar disorder. Clinicians should closely monitor for emerging manic or psychotic symptoms and provide timely interventions to prevent serious complications.