Negative Interpretation Bias As a Clinical Marker and a Scar of Depression: New Insights from a Large-Scale Study of the Scrambled Sentence Task in Formerly, Subclinically and Clinically Depressed Individuals.

Negative interpretation biases are thought to be clinical markers of depression and risk factors for its recurrence that would remain active after remission. Evidence on the conditions under which negative interpretation biases are active after remission is still unclear, and further studies are required to clarify whether negative interpretation biases are equivalent in magnitude at different depression conditions. A large-scale study of the Scrambled Sentence Task (SST) was conducted (639 participants), where different depression and never-depressed samples were compared in their performance in the SST through three experiments (i.e., formerly - Studies 1 and 2 -, subclinically - Study 2 - and clinically depressed individuals - Study 3 -). Cognitive load manipulations were used while completing the task. Formerly compared to never-depressed individuals showed higher negative interpretation biases at conditions of cognitive load only (Study 1). Formerly and subclinically depressed showed equivalent biases compared to never-depressed individuals (Study 2). Negative interpretation biases were further supported for clinically depressed (Study 3). Comparative analyses showed that both formerly and subclinically differed from clinically depressed individuals in their negative bias magnitude. These results prove the utility of the SST to detect negative interpretation biases in different depression conditions, including those recovered from depression. Results further show that negative bias magnitudes tend to decrease after remission but remain at subclinical levels, potentially conferring risk for depression recurrence.