"Sticky" thinking disrupts decision making for individuals with a tendency toward worry and depression.

Depressed individuals are commonly known to suffer from low mood. Less attention is paid to their decision-making deficiencies, consisting of indecisiveness and biased judgments. Many theories attempt to explain these impairments by focusing on reduced sensitivity to reward and punishment or biased information processing. Beyond these accounts, the present study explores another scenario, namely, whether the occurrence of sticky thinking-the occurrence of thoughts that are difficult to disengage from-could be a cause for the disruption of the decision-making process in individuals with depression. To test this hypothesis, we utilized the drift-diffusion model to investigate the influence of sticky thinking on the accumulation of evidence during a task commonly used to measure spontaneous thinking-the Sustained Attention to Response Task. Results showed that the more vulnerable group-specifically those with higher levels of repetitive negative thinking and depressive symptoms, including rumination-performed less accurately than the less vulnerable group. The more vulnerable group also showed a lower speed of evidence accumulation as evidenced by a decrease in the drift rate according to the drift-diffusion model. Moreover, the more vulnerable group exhibited prolonged nondecision time when more sticky thoughts occurred. At the neural level, we found that stronger alpha-band power marked more sticky thinking. We also demonstrated that the lower drift rate in the more vulnerable group, compared to the less vulnerable group, was exclusive to moments when the alpha-band power was higher than average. In summary, the study supported the idea that sticky thinking could explain the decision-making impairment among individuals who are more vulnerable to depression and worry. (PsycInfo Database Record (c) 2025 APA, all rights reserved).