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Hirofumi Hirakawa, MD, PhD

Decision-making capacity for treatment is a legal concept with a direct role in clinical practice. However, individuals with schizophrenia may lack the legal capacity to make treatment decisions.1 The symptoms of schizophrenia are divided into 3 main categories: positive symptoms, negative symptoms, and disorganization. Schizophrenia is associated with poor insight and cognitive dysfunction, which may influence decisional capacity.1 Therefore, it is important to assess decisional capacity in patients with schizophrenia. The MacArthur Competence Assessment Tool–Treatment (MacCAT-T)2 evaluates patients’ capacity to make decisions about their treatment based on given information consisting of 4 dimensions: understanding, appreciation, reasoning, and expression of a choice. A previous meta-analysis showed that schizophrenia patients had significant impairment in decision-making capacity for treatment as measured by the MacCAT in the context of clinical research and treatment compared to a healthy control group.3 However, this meta-analysis included only 3 studies of the MacCAT-T and did not evaluate the association between psychiatric symptoms and decision-making capacity for treatment.3 This report is a narrative review of the studies on schizophrenia that evaluated both decision-making capacity for treatment with the MacCAT-T and severity of symptoms using a clinical rating scale for schizophrenia.

The review of the literature was conducted in February 2022. The PubMed database was searched using the search terms the MacArthur Competence Assessment Tool for Treatment and schizophrenia. Only original studies that examined both decision-making capacity for treatment with the MacCAT-T and symptom severity using a clinical rating scale for schizophrenia such as the Brief Psychiatric Rating Scale (BPRS)4 or the Positive and Negative Syndrome Scale (PANSS)5 were included. Review articles and those not written in English were excluded. Eight published articles were identified.2,6–12

Patients with schizophrenia showed lower scores for understanding and reasoning than comparison participants without schizophrenia.2,6 One study11 found that schizophrenia patients exhibited lower scores in understanding, reasoning, and appreciation subscales of the MacCAT-T than did controls, and there were nonsignificant differences in the expression of a choice. Another study10 found that patients with schizophrenia scored significantly lower than internal medicine patients in all dimensions.

PANSS positive symptom scores were negatively associated with MacCAT-T subscale scores of understanding.11,12 PANSS positive symptoms were associated with a lack of decision-making capacity for treatment (odds ratio [OR]: 3.88).9 In particular, hallucinations were not associated with a lack of decision-making capacity for treatment (OR: 1.47), whereas delusions were associated with capacity (OR: 3.67).9 Interestingly, Grisso et al2 found strong negative correlations between understanding and conceptual disorganization and hallucinations, while no substantial correlation was found between understanding and unusual thought, contrary to the results of the study by Spencer et al.9 Some studies6–8 have reported no significant correlations between patients’ performance on any of the MacCAT-T subscales and positive symptoms.

Negative PANSS scores were found to be negatively associated with MacCAT-T subscale scores of understanding.8,11 Anergia negatively correlated with understanding, reasoning, and expressing a choice.10 Another study2 using the BPRS found that blunted affect was negatively associated with appreciation. In contrast, PANSS negative symptom scores did not correlate with understanding, appreciation, reasoning, or expressing a choice.12

Understanding was positively associated with the scores of depressive mood and guilt feelings and negatively associated with the scores of uncooperative behavior, disorientation, and mannerisms.2 Another study10 using the BPRS showed that disorientation was correlated with scores on all MacCAT-T dimensions (negatively associated with understanding, reasoning, and expressing a choice and positively associated with appreciation). The score for uncooperativeness was positively correlated with the score for appreciation.10 PANSS general psychopathology was negatively correlated with understanding, reasoning, and appreciation.8,11,12

In this report, the relationship between decision-making capacity for treatment with the MacCAT-T and the severity of symptoms using a clinical rating scale for schizophrenia is summarized. The literature shows that patients with schizophrenia were significantly less capable of making valid treatment decisions than control groups. Use of structured interviews such as the MacCAT-T is important to assess medical decision-making competence for schizophrenia. In addition, decision-making capacity for treatment in patients with schizophrenia was associated with positive and negative symptoms, general psychopathology, cognition, and insight. Therefore, when talking to patients with schizophrenia about their disease and treatment, it is important to use clear, easy to understand language and to repeat information in a manner similar to the informed consent process of Dunn et al,13 which used a computerized slide show incorporating more structure and review of important information.

Article Information

Published Online: June 1, 2023. https://doi.org/10.4088/PCC.22br03424

© 2023 Physicians Postgraduate Press, Inc.

To Cite: Hirakawa H. Assessing medical decision-making competence using the MacArthur Competence Assessment Tool–Treatment for schizophrenia. Prim Care Companion CNS Disord. 2023;25(3):22br03424.
Author Affiliations: Department of Neuropsychiatry, Oita University Faculty of Medicine, Oita, Japan (Hirakawa).
Corresponding Author: Hirofumi Hirakawa, MD, PhD, Department of Neuropsychiatry, Oita University Faculty of Medicine, Idaigaoka 1-1, Hasama-machi, Yufu City, Oita 879-5593, Japan (hira-hiro@oita-u.ac.jp).
Relevant Financial Relationships: None.
Funding/Support: None.