Temperament traits in seasonal affective disorder, suicide attempters with non-seasonal major depression and healthy controls.

Background: Very few studies have compared the temperament traits in matched suicidal and non-suicidal patients with major depression.
Methods: We compared the temperament traits in two matched groups of patients with major depressive disorder (MDD), MDD with seasonal subtype (SAD) without any suicide attempt (n = 23) and MDD without seasonal variation who attempted suicide (non-SAD SA), and compared the patients to matched healthy controls by using the Karolinska Scales of Personality (KSP) and the Marke-Nyman Temperament (MNT) questionnaires.
Results: Both the SAD and non-SAD SA groups showed significantly higher Somatic Anxiety, Muscular Tension, Psychasthenia, Irritability, Suspicion, and lower Socialization and Validity than the controls. The non-SAD SA group also showed significantly higher Psychic Anxiety, Detachment and Guilt as compared to controls. When the SAD and the non-SAD SA were compared, we found significantly higher Somatic Anxiety, Psychic Anxiety and Muscular Tension for the non-SAD SA group.
Conclusions: Both SAD and non-SAD SA patients display different temperament profiles compared to controls and in comparison with each other and the suicide attempters show especially high trait anxiety and hostility.
Clinical Relevance: The results suggest that trait anxiety and hostility, but not impulsivity, are associated with suicidal behavior in major depression.