Daily cortisol, stress reactivity and psychotic experiences in individuals at above average genetic risk for psychosis

Background. Hypothalamic-pituitary-adrenocortical (HPA) axis abnormalities have been found in patients with a psychotic disorder and first-degree relatives of patients with a psychotic disorder react with subtle increases in non-clinical psychotic experiences and negative emotions in the face of everyday stress. The current study investigated whether HPA axis functioning is altered in individuals at above average genetic risk for psychotic disorder, examining diurnal cortisol profiles, cortisol reactivity to daily stressors and the association between HPA axis activity and subclinical psychotic experiences. Method. Participants included siblings of patients with a psychotic disorder (n=60) and a healthy comparison group (n=63). The Experience Sampling Method (a structured diary technique) was employed to assess stress, psychotic experiences, negative affect and salivary cortisol repeatedly in the flow of daily life. Results. Multi-level analyses revealed higher diurnal cortisol levels and heightened cortisol reactivity to negative daily events in siblings compared with controls. Diurnal cortisol slope did not differ between the two groups, but momentary increases in psychotic experiences and negative affect were associated with increased cortisol in the sibling group. Conclusions. Findings support altered HPA axis activity in individuals at above average genetic risk for psychotic disorder, as evidenced by higher diurnal cortisol levels and increased cortisol reactivity to daily stress. Results also suggest a dynamic association between cortisol secretion and the intensity of psychotic-like experiences and negative emotions in daily life, although the direction of this association remains to be elucidated.