Biases in everyday reasoning: Associations with subclinical anxiety, depression and paranoia

Abstract

Background. Anxiety, depression and paranoia are frequently comorbid and cognitive models of these disorders refer to common reasoning biases. Previous literature exploring reasoning biases of the availability heuristic (invoked when thinking about the future) has distinguished between depression and paranoia but neglected to explore anxiety. This study explores heuristic reasoning biases in relation to levels of subclinical paranoia, depression and anxiety in a non‐clinical sample. Method. Two hundred and six healthy adults completed online measures of self‐reported anxiety, depression and paranoia and the Availability Test, assessing estimations of the likelihood of future neutral, positive and threatening events. Results. Robust past and future estimate correlations provided prima facie support for use of the availability heuristic. Over and above this, elevated levels of depression were associated with the tendency to underestimate the likelihood of future positive and neutral events, whereas subclinical paranoia was independently associated with overestimations of the likelihood of future threatening events. There was no evidence for associations between generalised anxiety and heuristic reasoning biases. Conclusion. The findings support those from clinical studies. It appears that depression and paranoia can be differentiated by the nature of their future‐oriented pessimistic thinking styles. The findings have clear implications for cognitive therapy for depression and paranoia.