Competence to consent and insight in schizophrenia: is there an association? A pilot study

The capacity to consent to treatment or research of patients with severe mental disorders is the focus of important ethical and clinical debate. Many studies evaluate the links between clinical symptoms and the capacity to consent. The aim of this study was to explore the correlations existing between the competence to consent to treatment and the level of awareness of the disease (insight) in patients suffering from schizophrenia in a cross-sectional study.

Participants included 60 outpatients meeting the criteria for a DSM-IV diagnosis of schizophrenia. Measures included the MacArthur Competence Assessment tool for Treatment (MacCAT-T), the Scale to Assess Unawareness of Mental Disorder (SUMD) and psychopathology rating scales including the Positive and Negative Syndrome Scale (PANSS).

The MacCAT-T dimension "Understanding" was found to be negatively correlated with negative and total PANSS scores but was not found to be correlated with any of the SUMD dimensions. However a systematic negative correlation was observed between the MacCAT-T "Appreciation" and "Reasoning" dimensions and the five SUMD dimensions. Finally, the MacCAT-T "Expressing a choice" dimension was found to be negatively correlated with two SUMD dimensions: "Having a mental disorder" and "consequences of the mental disorder".

These findings suggest an important correlation between the competence to consent to treatment and insight, a clinical variable currently assessed by clinicians. We hypothesized that this link could be mediated by cognitive impairments in schizophrenia. Emphasis should be placed on developing prospective studies comparing the courses of insight, cognitive disorders and capacity to consent in schizophrenia.