[Characteristics and impact of metacognitive deficits in schizophrenia]

The aim of this review of the literature is to summarise the definitions of metacognition, the measurement tools, the results of studies investigating metacognition in persons with schizophrenia and the therapeutic perspectives.

This review is based upon a selection of articles identified using a PubMed search containing the terms "schizophrenia" and "metacognition".

Cognitive deficits are present in 75 to 85% of persons with schizophrenia. According to the disability model of the World Health Organization, these cognitive deficits have an impact on social functioning, community integration and quality of life. However, heterogeneous results have been obtained by studies exploring the functional impact of cognitive deficits, suggesting that there is no direct relationship between these two characteristics. One possible explanation is that subjective factors, notably metacognition, may play an intermediate role moderating the link between cognitive deficits and functional impairment. Metacognition is defined as the evaluation and regulation of its own cognitive processes. The evaluation (or monitoring) monitors the accuracy and reliability of the cognitive task performance. Regulation (or control) promotes behavioural adjustment. Studies carried out in persons with schizophrenia show that most of them experience deficits in metacognitive performance. These metacognitive deficits are thought to be a key barrier to functioning in schizophrenia. Measurement tools are classified into two types: "independent" measurement of the cognitive task and "on line" measurements performed during the cognitive task. The subjective scale to investigate cognition in schizophrenia (SSTIC) and the metacognitive assessment scale (MAS) are two examples of questionnaires measuring metacognition independently of the cognitive task. Online measurements assess the metacognitive "monitoring" by asking the subject to evaluate between 0 and 100% of his/her degree of confidence in his/her response to a question. The metacognitive "control" is assessed by asking the subject to validate his/her answer. Convergent findings are reported by studies exploring metacognitive persons in people with schizophrenia. Dissociation between metacognitive monitoring and metacognitive control has been reported. Regarding metamemory, which has been currently the most studied area, no difference is observed between persons with schizophrenia and controls with respect to the metamemory judgement. However, subgroups of persons with schizophrenia differ significantly from controls: they are over-confident in their response if it is incorrect and they estimate more frequently than the controls if they do not know when their answer is correct. The relationships between metacognitive and cognitive deficits are complex in persons with schizophrenia, with poor matching between subjective and objective deficits. Several studies have reported that metacognitive difficulties strongly interfere with social functioning. It has been suggested that metacognitive deficits more strongly predict community functioning in persons with schizophrenia than cognitive deficits. Metacognitive skills may hence be viewed as a key factor in translating cognitive performance skills in daily life.

These data suggest that remediation programs specifically targeting metacognitive deficits have to be further developed.