Can cognitive deficits explain differential sensitivity to life events in psychosis?

Life events (LE) have been found to influence the onset and course of psychotic disorders. It has been suggested that LE have their effect by increasing underlying sensitivity to daily life stress, a reported vulnerability marker for psychosis. As increased stress-sensitivity and cognitive impairments have been shown to be negatively associated with each other in patient populations, it is attractive to hypothesise that the impact of LE on sensitivity to daily stress is modified by the degree of cognitive impairment, higher levels of cognitive impairment giving rise to reduced impact of LE on daily life stress-sensitivity.

Patients with psychotic illness (n = 42) were studied with a) a standard battery of neuropsychological tests to assess cognitive functioning, b) the Experience Sampling Method (a structured diary technique assessing current context and mood in daily life) to assess (i) appraised subjective stress related to daily events and activities, and (ii) emotional reactivity conceptualised as changes in both negative affect (NA) and positive affect (PA), and c) the Brown and Harris Life Event and Difficulties Schedule to assess LE over the last year.

Multilevel regression analyses showed that a prior history of LE increased the sensitivity for daily life stress in subjects with the best performance on the cognitive tests.

Subjects with cognitive impairments, who already were shown to have lower levels of sensitivity to daily life stress (Myin Germeys et al. 2002), may additionally be less reactive to prior exposure to LE. This result fits with the notion of separate affective and cognitive pathways of symptom formation in psychosis, the cognitive pathway being characterised by severe cognitive deficits and the affective pathway by increased levels of stress-sensitivity associated with prior exposure to LE.