Capacity to consent to psychotherapy: Reliability of the newly adapted German version of the MacArthur Competence Assessment Tool for Treatment for psychotherapy

BACKGROUND: Patients' capacity to consent to treatment (CCT) is a prerequisite for ethically sound informed consent in psychotherapy. The MacArthur Competence Assessment Tool for Treatment (MacCAT-T) is a reliable instrument for assessing CCT. A German version was adapted to the psychotherapeutical context (MacCAT-PT) to investigate its reliability and possible influences of age, education and prior experience with psychotherapy on CCT in a mixed clinical sample.

METHODS: N = 108 patients with indication for psychotherapy were recruited. The MacCAT-PT was administered by trained psychologists, took 20 min on average and was rated by the administering psychologist and an independent rater. Reliability statistics were investigated and regression analyses were conducted on MacCAT-PT scores and sociodemographic variables.

RESULTS: Sufficient to moderate inter-rater reliability (ICC = 0.80) and internal consistency (α = 0.80) were found for the total sum score of the MacCAT-PT and its scales, Understanding (ICC = 0.79, α = 0.77), Reasoning (ICC = 0.57, α = 0.65) and Making a Choice (ICC = 0.57). Appreciation featured an unacceptable inter-rater reliability (ICC = -0.01). Regression analyses indicated no significant effects.

CONCLUSION: These findings suggest that the MacCAT-PT is a reliable tool for assessing patients' overall CCT in psychotherapy. Psychometric properties of three scales were of good quality, while Appreciation needs to be reanalysed in patient samples with lower motivation for psychotherapy or limited CCT. The CCT may be suggested to be independent of age, education and prior experience. Future research should provide analyses focusing on structural and clinical validity in multiple clinical samples.