Competence to give informed consent in acute psychosis is associated with symptoms rather than diagnosis.

To investigate the association between competence to give informed consent to treatment, specific symptomology and diagnostic category, 110 inpatients diagnosed with DSM-IV acute schizophrenia (n = 64), schizoaffective disorder (n = 25) and bipolar affective disorder (n = 21) were interviewed using the MacArthur Competence Assessment Tool for Treatment (MacCAT-T) and the Positive and Negative Syndrome Scale (PANSS). Results indicated no significant difference in competence between the three disorders. Elevated positive, cognitive and excitement PANSS factor scores had lower MacCAT-T scores. Further analyses indicated symptoms that impair cognition; particularly, conceptual disorganisation and poor attention were most consistently related to poor performance on competence tests.