[Irritability associated with major depressive episodes: its relationship with mood disorders and temperament]

Irritability is a well-known feature of some mood states. Within the framework of major depressive episodes (MDEs) irritability has been associated with subtypes of depressive mood, personality traits, depressive mixed states, and a bipolar diathesis. This study aimed to assess the symptomatology of irritable depression and the effect of personality.

The study included 93 patients with MDEs, with and without other diagnoses. The characteristics and severity of depressive, manic, and anxious symptoms were assessed. Irritability was determined using the Irritability, Depression and Anxiety Scale outwardly directed irritability subscale (IDA-out). The patients were also administered the Multidimensional Assessment of Thymic States and the Irritability Questionnaire. Personality was assessed using the Temperament and Character Inventory-125 (TCI-125) and the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego (TEMPS-A).

More of the MDE patients with irritability (32.3%) had atypical features (i.e. weight gain and rejection sensitivity), guilt, hypomanic symptoms, depressive mixed states, and a personal and family history of bipolar disorder than the MDE patients without irritability. Irritability was moderately correlated with depression, hypomania, anxiety, and emotional reactivity. More of the irritable MDE patients exhibited increased novelty seeking, irritable and hyperthymic temperament scores, and had lower TCI-125 and TEMPS-A cooperation and harm avoidance scores than those that were not irritable. Forward logistic regression analysis showed that there was a strong independent association between irritability, and weight gain, irritable temperament, depressive mixed states, novelty seeking, and depression.

MDE-related irritability was strongly associated with atypical and mixed features, which may be indicative of a bipolar diathesis, as well as specific temperament characteristics that may be indicative of trait activation.