Is metacognitive training for psychosis effective?

Until the 1990s cognitive research in schizophrenia predominantly targeted ‘cold cognition’, that is deficits in neurocognitive faculties such as attention and memory impairment, which have been shown to compromise functional outcome [1]. In the past two decades the field has increasingly embraced cognitive biases, that is, distortions in the appraisal and processing of information. While cognitive biases are normal to a certain degree and in some cases may even promote well-being (e.g. unrealistic optimism, self-serving bias), escalation of some specific cognitive biases seem to play a role in the formation and maintenance of psychotic symptoms, particularly delusions. For example, a number of studies, recently summarized in two meta-analyses [2,3], demonstrated that patients with psychotic disorders and particularly those who experience delusions, jump to conclusions. Another literature indicates that patients are overconfident in their false judgements pertaining to memory, perception and social cognition [4,5]. Finally, a number of studies indicate that patients with psychosis are less open to counter-arguments, even for delusion-neutral scenarios [6].