By Christian Jarrett

Some researchers hope that focusing on the cognitive, neural, genetic and social processes that contribute to symptom dimensions – like anxiety-depression or social withdrawal – may be more fruitful than trying to understand the causes of different diagnostic categories, like “schizophrenia” or “major depression”. It’s in this vein that a new paper in Biological Psychiatry has used a simple perceptual task to investigate how judgment confidence, judgment accuracy and metacognition (judgment insight) are related to various trans-diagnostic symptom dimensions in the general public.

Across two experiments, Marion Rouault at UCL and her colleagues asked nearly a thousand participants recruited online to complete surveys about their experience of various psychiatric symptoms, from impulsivity to anxiety to schizotypy. The researchers looked for correlations between different symptoms and found that they grouped into three key dimensions: anxiety and depression, compulsive behaviour and intrusive thoughts, and social withdrawal.

Next, the participants all performed the same perceptual judgment many dozens of times: decide which of two adjacent boxes contained the most dots, and they rated their confidence in each decision.

As they judged each pair of boxes, the participants weren’t given any feedback on their performance. However, in the second experiment, the task difficulty was continually adjusted for each participant so that their accuracy was kept constant and comparable to other participants (this was so the researchers could examine participants’ confidence and insight into their own judgment accuracy independent of their actual perceptual ability).

The researchers found that the participants’ experience of different mental health symptoms was not related to their accuracy at the perceptual task (unlike older age and lower IQ, which were both related to poorer accuracy, as you might expect).

Intriguingly, however, participants who scored higher on the anxiety-depression symptom dimension showed a consistent tendency towards being less confident in their judgments, and yet they showed more accurate metacognition – that is, their confidence more appropriately tracked their actual accuracy from one trial to the next. Perhaps in everyday life this blend of bias and insight might manifest as pessimism and harshly honest self-evaluation (which could contribute to problems in everyday life when you consider that sometimes a little over-confidence can give us the impetus to tackle important challenges).

In contrast, participants who scored higher on the “compulsive behaviour and intrusive thought” symptom dimension showed the opposite pattern – they were consistently more confident in their judgments, yet showed less accurate metacognition. This symptom dimension is shared by people who are diagnosed with schizophrenia, OCD and eating disorders, and one can imagine the mix of over-confidence and lack of insight playing out in everyday life in terms of jumping to conclusions and holding harmful convictions about the self.

“Our findings reveal that shifts in metacognitive evaluation represent a specific and pervasive behavioral correlate of subclinical psychopathology,” the researchers said, adding that, “…The anxiety-depression and compulsive behaviour-intrusive thought dimensions show equal and opposite relationships between two key aspects of metacognition – confidence and meta-cognitive accuracy.”

From a methodological perspective, it’s notable that these patterns would have remained hidden if, rather than looking at symptom dimensions, the researchers had used participants’ scores on questionnaires tapping specific symptoms and diagnostic categories in isolation.

This study should be considered preliminary. The sample was from the general public and the researchers relied on the participants’ reports of their own symptoms. The findings might be different with clinical samples. It also remains to be seen if the symptom-related patterns of confidence and insight uncovered here would apply to other contexts beyond the specific perceptual task that was used. The researchers predict they will: “Recent evidence points towards metacognition relying in part on domain-general resources, suggesting that the findings from the current study are likely to generalise to other scenarios,” they said.

—Psychiatric symptom dimensions are associated with dissociable shifts in metacognition but not task performance

Christian Jarrett (@Psych_Writer) is Editor of BPS Research Digest