The vulnerability-stress model of psychotic disorders describes, in essence, an interaction between personal vulnerability and environmental stressors. The present study investigated this interaction and studied emotional reactivity to daily life stress as a vulnerability marker for psychotic illness.
Patients with psychotic illness (n = 42), their first-degree relatives (n = 47), and control subjects (n = 49) were studied with the Experience Sampling Method (a structured diary technique assessing thoughts, current context, and mood in daily life) to assess (1) appraised subjective stress of daily events and smaller disturbances in daily life and (2) emotional reactivity conceptualized as changes in both negative affect and positive affect.
Multilevel regression analyses showed that an increase in subjective stress was associated with an increase in negative affect and a decrease in positive affect in all groups. However, the groups differed quantitatively in their pattern of reactions to stress. Patients with psychotic illness reacted with more intense emotions to subjective appraisals of stress in daily life than control subjects. The decrease in positive affect in the relatives was similar to that of the patients, while the increase in negative affect in this group was intermediary to that of patients and control subjects.
Higher levels of familial risk for psychosis were associated with higher levels of emotional reactivity to daily life stress in a dose-response fashion. Subtle alterations in the way persons interact with their environment may constitute part of the vulnerability for psychotic illness.