Biogenetic temperament and character in insomnia and depression

Objective: We compared the biogenetic temperaments and characters of primary insomnia patients, major depressive disorder (MDD) patients with insomnia, MDD patients without insomnia, and normal controls. Methods: A total of 417 participants were recruited from a community and a psychiatric clinic in South Korea. Subjects were divided into 4 groups based on the Structured Clinical Interview for DSM-IV axis I disorder (SCID-IV) and sleep questionnaire: 1) normal controls (n = 314), 2) primary insomnia (n = 33), 3) MDD without insomnia (n = 30), and 4) MDD with insomnia (n = 40). All participants were requested to complete the Temperament and Character Inventory. Results: There were significant between-group differences in harm avoidance (HA)(F = 32.96, p < 0.001), reward dependence (RD)(F = 5.21, p < 0.01), self-directedness (SD)(F = 24.72, p < 0.001) and cooperativeness (CO)(F = 15.75, p < 0.001), after controlling for age and gender. Subjects with primary insomnia showed higher HA and lower SD than normal control, but lower HA and higher SD than MDD patients with insomnia. CO was lower in MDD patients, but not in subjects with primary insomnia. Lower RD was found only in MDD patients with insomnia. Conclusion: The current study suggests that high HA and low SD were related to primary insomnia, although these patterns were more prominent in patients with MDD.