Grandiose delusions in individuals with schizophrenia are associated with positive symptoms such as hallucinations and optimism for the future, according to a study published in Schizophrenia Research. These symptoms further play a role in the maintenance of grandiose delusions, which may be a coping mechanism in this population. The investigators of this cross-sectional study sought to understand how the expectations for the future and sensitivity to reward contribute to grandiose delusions in schizophrenia disorder and whether specific measures of positive and negative symptoms, as well as depression were associated with grandiose delusions.

The study sample included 115 patients diagnosed with schizophrenia disorder recruited from the Departments of Adult Psychiatry in France. Grandiose and persecutory delusions were evaluated using specific items from the Positive and the Negative Syndrome Scale, Scale for the Assessment of Negative Symptoms, and the Calgary Depression Scale. The Sensitivity to Punishment and Reward Questionnaire short version was used to measure sensitivity to punishment and reward. Future expectations were assessed using a task in which the participants were asked to estimate the probability that certain positive, negative, and neutral situations will occur in the future. Correlation and Linear Regression models were used to test the extent to which grandiose delusions are associated with future expectations, sensitivity to reward, depression, and positive and negative symptoms.

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The study results showed that hallucinations and positive expectations for the future were significantly associated with grandiose delusions, but not future negative or neutral expectations nor depression or negative symptoms. Higher sensitivity to reward was associated with higher levels of grandiose delusions, but not when other factors or clinical variables were considered. These findings suggest that individuals with grandiose delusions have more positive symptoms and are more optimistic about the future as part of the underlying psychological process associated with the maintenance of these delusions, which allow them to cope with stress and adversity caused by their disease.

Limitations to the study included the cross-sectional design in which the causal relationship is difficult to infer, and that a control population was not used, preventing the ability to determine optimism bias. Furthermore, the task used to measure future expectations only explained a small variation of grandiose delusions specific to everyday situations and not related to personal expectations or to the content of the delusions.

The investigators suggest that optimism for the future may be an important psychological process associated with the maintenance of grandiose delusions in patients with schizophrenia. Grandiose delusions may be further maintained in patients who interpret hallucinations as a kind of special ability or power.


Bortolon C, Yazbek H, Norton J, Capdevielle D, Raffard S. The contribution of optimism and hallucinations to grandiose delusions in individuals with schizophrenia [published online January 10, 2019]. Schizophr Res. doi: 10.1016/j.schres.2018.12.037