Behavioral, neurocognitive and treatment overlap between attention-deficit/hyperactivity disorder and mood instability.

Attention-deficit/hyperactivity disorder (ADHD) is a common and debilitating psychiatric disorder characterized by symptoms of inattention, impulsivity and motor restlessness. Consistently noted alongside these symptoms is mood instability in the form of irritability, volatility, swift changes in mood, hot temper and low frustration tolerance. The current diagnostic classification systems do not include mood instability as a core aspect of ADHD, but rather as an associated feature of the disorder. However, the literature suggests that overlapping cognitive deficits and neuroanatomical substrates may underlie both the classical ADHD symptoms and mood instability. Furthermore, common neurotherapeutic interventions in the form of stimulant medications or atomoxetine may help to alleviate both types of symptoms when they co-occur. This research suggests that mood instability and symptoms of ADHD may be interlinked and that mood instability may be better understood as a core feature of the ADHD syndrome.