Methylphenidate-Induced Hypomania in an Adult with Undiagnosed Bipolar II Disorder and ADHD: A Case Report

Abstract

Methylphenidate is a first-line pharmacological agent for attention-deficit/hyperactivity disorder (ADHD). While generally well-tolerated, it may precipitate hypomania or mania, especially in patients with underlying bipolar spectrum disorders. A 34-year-old man presented with features of hypomania, including elevated mood, reduced need for sleep, and impulsive behavior, after initiating methylphenidate for presumed adult ADHD. Subsequent psychiatric evaluation uncovered an undiagnosed history consistent with bipolar II disorder. Methylphenidate was discontinued and mood stabilized with lamotrigine and psychoeducation. This case highlights the potential for psychostimulants to induce mood episodes in individuals with latent bipolarity, underscoring the importance of comprehensive psychiatric evaluation prior to initiating stimulant therapy.