Psychological processes underlying delusional thinking in late-onset psychosis: a preliminary investigation

It has been suggested that delusions may serve as a defence against negative self-representations. The present study investigated general psychological well-being and evidence for defensive emotional processes among people with late-onset psychosis.

The performance and responses of older people with late-onset psychosis (n = 13), older people with depression (n = 15), and age-matched healthy controls (n = 15) were compared in a cross-sectional design. Participants rated their own levels of depression and self-esteem, and completed an emotional Stroop task to establish whether there was evidence of implicit depression in the absence of explicit acknowledgement. Participants rated themselves on a number of personal attributes in relation to two life stages to generate discrepancies in 'actual', 'ideal' and 'other' self-concepts, and completed measures of their perceptions of current and past psychological well-being.

People with late-onset psychosis showed no evidence of overt depression or low-self esteem. All three groups showed an attentional bias to depression-related and age-related words, although response times overall were faster for controls. The psychosis group showed no discrepancies between either their past or their current 'actual' and 'other' self-concepts, suggesting that they do not have more negative views about how others see them.

Evidence from this study does not support the application of the 'delusion-as-defence' model to late-onset psychosis, but methodological constraints must be borne in mind when interpreting the findings.