Lack of association between conversation partners' nonverbal behavior predicts recurrence of depression, independently of personality.

High neuroticism and low extraversion are related to depression and its recurrence. We investigated whether nonverbal involvement behavior during social interaction is one of the factors via which these relations are effectuated. We measured nonverbal expressions of involvement from videotaped behavior of remitted depressed outpatients (n=101) and their conversation partners, and assessed self-reported neuroticism and extraversion scores. During a 2-year follow-up, we assessed the recurrence of depression. Twenty-eight participants (27.7%) experienced a recurrent episode. Time to recurrence was predicted by neuroticism and extraversion, and also by the degree of association between levels of nonverbal involvement behavior of conversation partners. The behavioral effect did not explain the personality effect. Neuroticism moderated the behavioral effect. The results point to the independent relevance of personality and nonverbal behavior in the long-term course of depressive disorder.