Defective Self and/or Other Mentalising in Schizophrenia: A Cognitive Neuropsychological Approach.

The mentalising abilities of schizophrenic patients and normal controls were tested using picture sequencing and story-telling tasks that required subjects to infer causal mental states in story characters, and a recall task that required subjects to dissociate subjective mental states from objective realities. Selective mentalising deficits were found in some patients. For other patients, general sequencing errors, "sensory" mentalising, and poor recall of symbolic representations suggested more profound problems. Task results were best accounted for by dissociable cognitive abnormalities, rather than graded dysfunction of a central mentalising mechanism. Symptom profiles of patient subgroups and correlations between task measures and clinical ratings linked these cognitive abnormalities to specific symptoms. General sequencing difficulty was associated with both poverty symptoms and reality distortion, suggesting that two mechanisms may underpin such errors: one, inability to manipulate symbolic representations, being linked to poverty; the other, failure to critically evaluate plausible cause-and-effect, being linked to reality distortion. There was some evidence that defective self-monitoring underpins thought disorder. Impaired metarepresentation was linked to the autisticlike symptoms of flat affect, social dysfunction, and alogia, rather than reality distortion. Implications of these findings are discussed with respect to theoretical and methodological issues confronting current schizophrenia research.