Low-dose quetiapine induced or worsened mania in the context of possible undertreatment

Bipolar disorder is a mental illness with a lifetime prevalence of 2% and has a dramatic impact on quality of life. Mania is a distinct period of abnormal and sustained elevated, expansive, or irritable mood and increase in goal-directed activity or energy that lasts at least 1 week and is present for most of each day. Quetiapine is an atypical antipsychotic approved for the treatment of bipolar depression and mania. For the treatment of acute mania, a dose of 600 to 800 mg/day is recommended. There has been concern of potential induction or worsening of hypomanic or manic symptoms at low doses via the ratio of 5HT2A/D2 receptor antagonism, which at lower doses favors greater 5HT2A receptor blockade and thus increases dopamine concentrations. This article describes a case report of hypomania worsening to mania with psychotic features in a drug-naïve patient who was started on low-dose quetiapine. This case adds to the existing literature of case reports indicating that low-dose quetiapine may be associated with induction or worsening of hypomanic/manic symptoms, while acknowledging the difficulty of suggesting a causal relationship.