An intersubjective perspective on negative symptoms of schizophrenia: implications of simulation theory

The majority of neurocognitive models of negative symptoms in schizophrenia focus on failures to construct and sustain accurate representations of others and the world. Rarely considered are the intersubjective dimensions of negative symptoms as well as the mechanisms that sustain such symptoms. This paper critically analyses neurocognitive models of schizophrenia based on Theory of Mind (TOM) deficits and describes an alternative model of negative symptoms of schizophrenia based on Simulation Theory. We assert that several forms of negative symptoms of schizophrenia can be explained by an inability to express oneself, participate in, or be attuned to the context of social interactions. We label this deficit disadherence and suggest it may result from dysfunctions in "mirror" neurons. In particular, we suggest that patients with schizophrenia are unable to construct an inner model of the mind of another person and "select", from among various hypotheses, the one most suited to immediately understand the meanings and goals of interpersonal interactions. Moreover dysfunction in both "canonical" and "mirror" neurons, situated for the most part in the premotor and parietal cortex, could cause psychomotor negative symptoms. These hypotheses are explored in the context of a single case study.