Solitude and cortisol: associations with state and trait affect in daily life

The social context can impact psychological and physiological functioning. Being alone, in particular, is experienced as more negative on average than being with others, in both normative and pathological populations. This study investigates whether daily solitude is associated with changes in cortisol and, if so, whether momentary and trait affect can explain this relationship. Forty-four female college students used the Experience Sampling Method during a week, completing questionnaires and collecting saliva 8 times daily. Effects of current solitude, affect, and trait affectivity on cortisol were tested with multilevel regression. Cortisol levels were significantly higher when individuals were alone. Although momentary affective states changed during solitude and were also associated with cortisol, they did not fully explain the effects of solitude on cortisol. Trait affectivity moderated the association between solitude and cortisol. Findings may help clarify how daily experience may heighten risk of depression or other negative health outcomes in vulnerable individuals.