Acute-Onset Bipolar Psychosis in an Adolescent Without Prodromal Symptoms: A Case Report

Early-onset bipolar disorder often begins in adolescence and carries greater severity, comorbidity, and longterm impairment.Diagnosis is complicated by symptom overlap with normative developmental behavior, nonspecific prodromes, and conditions that can cause high-risk or impulsive behaviors, such as attention deficit/hyperactivity disorder (ADHD).This report examines the case of an adolescent with the acute onset of bipolar disorder and psychosis without an identifiable prodrome, after stimulant-treated ADHD, with emphasis on evaluation, treatment, and outcome.A 15-year-old male child with a history of anxiety and ADHD since childhood (well-controlled on dexmethylphenidate hydrochloride extended-release (XR)) presented after two weeks of abrupt restlessness, racing thoughts, decreased sleep, pacing, pressured speech, disorganization, echolalia, episodic disrobing/soiling, and paranoid delusions.He was admitted to the inpatient adolescent psychiatry unit for altered mental status with mania and psychosis.Risperidone was initiated and titrated to 1 mg in the morning and 2 mg nightly, with marked clinical improvement in manic and psychotic symptoms within one week, suggesting an original decrease in dosage may have precipitated psychosis.No organic etiology was revealed on magnetic resonance imaging (MRI), lumbar puncture, labs, or encephalitis panels.Given the patient's clinical improvement, he was discharged on risperidone with first-break psychosis clinic follow-up.The patient tolerated long-term dexmethylphenidate hydrochloride use without prior manic symptoms, and discontinuation did not improve his presentation, making stimulant-induced bipolar disorder less likely.An extensive workup, including MRI, cerebrospinal fluid (CSF), and infectious/autoimmune panels, ruled out encephalitis.The case documents an abrupt-onset severe bipolar episode with psychosis in the absence of a prodrome; the temporal risperidone reduction may have precipitated decompensation.This case highlights the need for thorough multidisciplinary evaluation to exclude medical etiology, structured medication-transition protocols, and close outpatient follow-up.