Abnormalities of confidence in psychiatry: an overview and future perspectives

Abstract

Our behavior is constantly accompanied by a sense of confidence and its' precision is critical for adequate adaptation and survival. Importantly, abnormal confidence judgments that do not reflect reality may play a crucial role in pathological decision-making typically seen in psychiatric disorders. In this review, we propose abnormalities of confidence as a new model of interpreting psychiatric symptoms. We hypothesize a dysfunction of confidence at the root of psychiatric symptoms either expressed subclinically in the general population or clinically in the patient population. Our review reveals a robust association between confidence abnormalities and psychiatric symptomatology. Confidence abnormalities are present in subclinical/prodromal phases of psychiatric disorders, show a positive relationship with symptom severity, and appear to normalize after recovery. In the reviewed literature, the strongest evidence was found for a decline in confidence in (sub)clinical OCD, and for a decrease in confidence discrimination in (sub)clinical schizophrenia. We found suggestive evidence for increased/decreased confidence in addiction and depression/anxiety, respectively. Confidence abnormalities may help to understand underlying psychopathological substrates across disorders, and should thus be considered transdiagnostically. This review provides clear evidence for confidence abnormalities in different psychiatric disorders, identifies current knowledge gaps and supplies suggestions for future avenues. As such, it may guide future translational research into the underlying processes governing these abnormalities, as well as future interventions to restore them.

Fig. 1. Measures of confidence.

Confidence measures can be divided into general measures of confidence level and precision measures of confidence estimation. To assess someone’s general level of confidence, confidence level or calibration can be analyzed. Calibration (or confidence bias) is usually calculated as the difference between mean task performance and confidence. This results in overconfidence when confidence levels are higher than performance levels, and underconfidence vice versa. To assess someone’s precision of confidence estimation, confidence discrimination, metacognitive sensitivity or metacognitive efficiency can be analyzed. Confidence discrimination refers to the difference in confidence levels between correct and incorrect choices. The larger this difference, the higher the discriminatory accuracy of confidence, signaling an increased ability to recognize accurate from inaccurate performance by using one’s metacognitive report. Confidence discrimination is sometimes referred to as ‘the confidence gap’. Confidence bias and discrimination are two independent aspects of metacognition: an individual might be underconfident, but still be highly sensitive to discriminate between accurate and inaccurate performance with their confidence. Similar to discrimination, metacognitive sensitivity, also referred to as parameter meta-d’, aims to measure the ability of a metacognitive observer to discriminate between correct and incorrect trials with their confidence judgments. Yet, it uses a more sophisticated calculation that is bias free, and controls for performance confounds. On the other hand, metacognitive efficiency, referred to as meta-d’/d’, indicates how well perceptual information (d’) is used to form a metacognitive report (meta-d’). When meta-d’/d’, or the M-ratio, equals 1 (i.e. indicated by the line in the graph), this signals a metacognitively ideal observer that uses all perceptual information captured in d’ for the formation of a metacognitive report. When meta-d’/d’ < 1, not all information was used to form a metacognitive report, corresponding to lower metacognitive efficiency. When meta-d’/d’ > 1, the observer retrieved additional information to form a metacognitive report, corresponding to higher metacognitive efficiency

Fig. 2. Confidence differences confounded by intergroup differences in first-order performance.

a The difference in first-order performance between groups might result in untrue differences of confidence between groups. b First-order performance is equal between groups and therefore specific effects of group identity on confidence are isolated. This figure illustrates the need for bias free measures, such as meta-d’ and metacognitive efficiency, which control for performance differences between groups

Fig. 3. Overall confidence abnormalities in (sub)clinical psychiatry.

This figure shows the overall abnormalities in confidence processes in different (sub)clinical psychiatric disorders (versus healthy controls in clinical patient groups). Every study is represented by one data point (circle or triangle). When a study existed of multiple experiments testing different populations, multiple data points were used. For all clinical studies, the sample size of the patient group is displayed. Different colors are used for subclinical (light blue) and clinical (dark blue) populations. Different symbols represent increases (on upper line) no change (middle line) or decreases (lower line) of general confidence level (circles) or precision of confidence estimation (triangles). Studies that controlled for performance biases, be it by using the bias-free meta-d’ framework, or by showing (or actively keeping) equal performance levels between groups, are outlined. For studies investigating schizophrenia that found both an increase in confidence for errors as well as a decrease in discrimination, the latter effect is displayed in this figure. The subclinical study by Rouault et al. is included in all four disorder categories. For explanation of the different confidence measures, see Fig. 1. OCD obsessive-compulsive disorder, MDD/ANX depression/anxiety disorders