Cognitive Biases and Delusions in Psychosis

Cognitive biases are systematic deviations in information processing that contribute to the emergence and persistence of delusional beliefs in psychosis. Core biases include a tendency to gather insufficient evidence before forming conclusions, known as the jumping to conclusions (JTC) bias, and a bias against disconfirmatory evidence (BADE), which involves discounting information that contradicts one’s beliefs. These biases operate in concert with lowered decision thresholds and overconfidence in inferences, promoting the premature acceptance and maintenance of false beliefs. Delusional ideation often reflects an imbalance between rapid, heuristic judgements and slower, analytic reasoning, leading to impaired reality testing and social functioning. Recent advances in computational psychology and neuroimaging have begun to map the neural circuits underlying these biases, implicating aberrant salience attribution, altered reward learning and disrupted uncertainty signalling. Understanding these mechanisms informs the design of targeted interventions that enhance belief flexibility, improve evidence integration and foster metacognitive awareness, thereby reducing symptom severity and improving functional outcomes.

Research from Nature Portfolio

Recent studies have delineated distinct decision-making processes that underlie different delusional themes. In a cohort comprising individuals with schizophrenia-spectrum psychosis and matched healthy controls, researchers assessed performance on probabilistic reversal learning and explore–exploit tasks alongside self-reported reasoning measures. Elevated win-switch rates, heightened random exploration and reduced integration of disconfirmatory evidence were found to predict levels of paranoia independently. By contrast, self-reported hasty decision-making correlated specifically with non-paranoid delusional ideation. Computational modelling revealed that parameters indexing environmental volatility and behavioural variability significantly improved the prediction of paranoid thinking. These findings clarify how distinct cognitive mechanisms contribute to different delusional subtypes and suggest that interventions targeting volatility-driven decision processes may be particularly effective in reducing paranoia.

Cognitive Biases and Delusions in Psychosis publication trend

The graph below shows the total number of articles in cognitive biases and delusions in psychosis across all publications each year (not limited to Nature Index journals).

Technical terms

Jumping to Conclusions (JTC) bias: A decision-making style characterised by reaching firm conclusions with minimal evidence.

Bias Against Disconfirmatory Evidence (BADE): The tendency to ignore or discount information that contradicts existing beliefs.

Belief Flexibility: The capacity to consider alternative explanations and revise beliefs in light of new evidence.

Probabilistic Reversal Learning: A task measuring adaptability to changing reward contingencies by assessing how quickly individuals adjust choices when reinforcement patterns shift.

Delusional Ideation: The formation and maintenance of false beliefs that persist despite clear contradictory evidence.

References

1. Cannabis use and cognitive biases in people with first-episode psychosis and their siblings. Psychological Medicine (2024).
2. Relationships between cognitive biases, decision-making, and delusions. Scientific Reports (2023).
3. A Novel Approach to Assessing the Jumping to Conclusions bias: Evidence of Validity from the Real-Life Paradigm. Psychiatry Research (2024).
4. A two-stage cognitive theory of the positive symptoms of psychosis. Highlighting the role of lowered decision thresholds. Journal of Behavior Therapy and Experimental Psychiatry (2016).
5. Fast and slow thinking in distressing delusions: A review of the literature and implications for targeted therapy. Schizophrenia Research (2017).