Rapid Improvement with Mirtazapine in a 14-Year-Old Adolescent Diagnosed with Hypomania: A Case Report

This case report describes a 14-year-old male patient diagnosed with hypomania who demonstrated a rapid and marked clinical improvement following the addition of mirtazapine to his treatment regimen. The clinical significance of this case lies in highlighting both the potential manageability of childhood mood disorders through early intervention and the possible influence of genetic vulnerability, given a family history of schizoaffective disorder and suicide. The patient presented with a one-year history of increasing anger, violent tendencies, extreme emotional reactivity, insomnia episodes lasting up to two consecutive nights, restlessness, distractibility, subthreshold flight of ideas, abrupt school dropout, evening exacerbation of symptoms, excessive speech, swearing, subthreshold grandiosity, and recurrent episodes of running away from home. Multiple previous pharmacological treatments—including lurasidone 80 mg, methylphenidate 36 mg, zuclopenthixol depot injection, fluoxetine 20 mg, risperidone 1 mg, and escitalopram 10 mg—were ineffective, and several were associated with worsening irritability. Valproic acid (depakine) 500 mg three times daily and aripiprazole 20 mg were initiated for hypomania; however, increasing anger attacks necessitated the addition of chlorpromazine 100 mg, without clinical benefit. Following the introduction of mirtazapine 15 mg for prominent anxiety and insomnia, irritability and temper tantrums resolved completely within two weeks, with full clinical recovery observed at one month. This case suggests that mirtazapine may have a role as an adjunctive treatment in selected pediatric mood disorder cases and underscores the importance of individualized, early therapeutic strategies.