Theory of mind in Asperger's syndrome, schizophrenia and personality disordered forensic patients.

INTRODUCTION: The ability to conceptualise other individuals' mental states is dependent on having a 'theory of mind' (ToM). Individuals with Asperger's syndrome typically display ToM impairments, as do some individuals with schizophrenia, notably those with paranoid delusions. The presenting features of these and other individuals, such as those with some personality disorders, particularly in forensic patients, are often unclear. ToM performance was examined to see whether it could distinguish forensic patients with Asperger's syndrome from other patient groups.
METHODS: The performance of three male patient groups (N = 39) detained in high security psychiatric care, including those with Asperger's syndrome, schizophrenia (with paranoid delusions and/or auditory hallucinations as their predominant symptoms), or a dissocial and/or borderline personality disorder were compared using the revised eyes task and the modified advanced ToM test.
RESULTS: The Asperger's syndrome and schizophrenia groups performed significantly worse than the personality disorder group on both ToM measures. However, the Asperger's syndrome and the personality disorder groups had significantly higher levels of general intellectual functioning than the schizophrenia group.
CONCLUSIONS: Whilst ToM performance may help to discriminate patients with Asperger's syndrome or schizophrenia from personality disorder ed patients, a wide range in performance made it difficult to specify a patient to a particular group. Theoretical and methodological issues are discussed along with the usefulness of ToM assessments with forensic patients.