β = standardised beta coefficient, r = correlation coefficient, p = p-value, AD = Anxious-Depression, CIT = Compulsivity and Intrusive Thought, SW = Social Withdrawal. The error bars represent the standard error around the standardised beta coefficient. (A) AD and CIT were associated with metacognitive bias, while SW was not. (B) The residual values for confidence (controlling for age, gender and education) were negatively associated with AD. (C) The residual values for confidence (controlling for age, gender and education) were positively associated with CIT.

β = standardised beta coefficient, AD = Anxious-Depression, CIT = Compulsivity and Intrusive Thought, SW = Social Withdrawal, OCD = Obsessive compulsive disorder, r = correlation coefficient, p = p-value (unadjusted), *** = p <0.001, ** = p <0.01, * = p <0.05. (A) Psychopathology symptoms improved with four weeks of iCBT. (B) Confidence was significantly higher and, (C) the task was more difficult at four-week follow-up. (D) Those with the largest improvements in AD had the greater increases in confidence. (E) Change in confidence also scaled with improvements in trait anxiety, depression and alcohol misuse.

β = standardised beta coefficient, AD = Anxious-Depression, CIT = Compulsivity and Intrusive Thought, SW = Social Withdrawal, OCD = Obsessive compulsive disorder, r = correlation coefficient, p = p-value, *** = p<0.001, ** = p<0.01, * = p<0.05. (A) The majority of psychiatric scales improved in the antidepressant arm after 4 weeks of treatment, while the controls only had significant reductions in OCD symptoms and alcohol misuse at follow-up. (B) The larger increase in confidence in the antidepressant arm compared to controls was trended towards significant. (C) The antidepressant arm had a greater increase in task difficulty (a reduction in dot difference across stimuli) from baseline to follow-up, relative to controls. (D) Although not significant, the association between change in confidence and change in anxious-depression was in the expected negative direction in the antidepressant arm and among controls.

(A) Participant flow chart (CONSORT chart). Participants were considered ‘completers’ if they had metacognitive and transdiagnostic psychiatric dimension data at baseline and follow-up and met task inclusion criteria. (B) Overview of study design from study intake (week 0) to follow-up (week 4) assessments across groups. (C) Metacognitive (visuo-perceptual decision-making) task design (N = 210 trials). On each trial, participants were asked to judge and choose the sunflower that contained more seeds (i.e., higher number of dots) and then provide a confidence rating on their decision.

Baseline Sociodemographic Characteristics of Participants.

Correlation between Items Weights from Factor Analysis of Transdiagnostic Dimensions.

Changes in Psychiatric Dimensions and Scale Scores from Baseline to Follow-up in the iCBT Arm.

The Interaction Effect of Time and Psychiatric Dimension/Scale Change on Mean Confidence in the iCBT Arm.

Changes in Psychiatric Dimensions and Scale Scores from Baseline to Follow-up in Antidepressant and Control Arms.