Table 2 Results from Empirical Studies

Appelbaum et al. (1999)[17]

26 female outpatients pre-selected on basis that they were able to communicate.

DSM–IV major depression.

Research participation

MacCAT-CR scores on understanding, reasoning and appreciating abilities.

Assessment of decision-making abilities to consent to research.

Most subjects performed well on ability measures, maintaining this over the course of their admission. Low scores in appreciation and reasoning measures were recorded in a small subgroup.

HDRS

Mean scores for: understanding 23.33 (out of max 26); appreciation 4.89 (out of max 6); reasoning 6.5 (out of max 8).

Mean Score = 18

Range = 15-25

Cohen et al. (2004)[18]

20 psychiatric inpatients

DSM-IV major depression.

Research participation

MacCAT-CR scores on understanding, reasoning and appreciating abilities.

Assessment of decision-making abilities to consent to 2 research protocols with different risks.

Subjectstended to score in the highest range of all three abilities for both research protocols. The poorest scores were in reasoning but with 90% scoring above the mid point of the reasoning scale in the high-risk study.

BDI

Mean score = 41

SD = 9.5

Bean et al. (1994/1996)[19, 20]

96 psychiatric inpatients referred for ECT

‘Major depression unresponsive to medication’ (Personal correspondence from author). Depression type and symptom severity not given in paper.

Treatment participation

Competency Schedule (CIS) scores (a 15 item questionnaire which the authors try to map to 4 standards: evidencing a choice, understanding the issues related to treatment, evidence for a rational reason for the choice, appreciation of the nature of the situation).

To compare physicians’ judgements of competency with scores on the CIS.

Complex presentation of findings. Physician judgments of competency in depressed patients awaiting potential ECT matched well with CIS scores. The item on the CIS that assesses a patients’ ability to specify (or know) the potential benefits of treatment is the best single discriminator of physician judgement (Wilk’s Lambda = 0.49). The authors map this ability to “understanding the issues related to treatment” though, in MacCAT terms, it would map to appreciation: acknowledgement of potential benefit of treatment.

Unstructured physician judgments of competency.

21 patients (21.9%) were categorized by the physician as unable to give consent for ECT.

Grisso & Appelbaum (1995)[21]

92 psychiatric inpatients

DSM-IV Major depression. (Severity not reported)

Treatment participation

Pre-cursor instruments to MacCAT-T. Scores on understanding, appreciation and reasoning abilities.

Assessment of decision-making abilities to consent to treatment.

Most subjects scored well on all abilities. Appreciation was most impaired ability. Subjects with scores indicating impairment in: understanding n = 5, (5.4%); appreciation n = 11 (12.0%); reasoning n = 7 (7.6%).

Compound measures: understanding and/or appreciation n = 17 (18.5%); understanding and/or reasoning n = 11 (12.0%); appreciation and/or reasoning n = 17 (18.5%); understanding, appreciation and/or reasoning n = 22 (23.9%).

Lapid et al. (2003)[22]

40 psychiatric inpatients referred for ECT

DSM-IV major depression including unipolar, bipolar and schizoaffective depression.

Treatment participation

MacCAT-T scores on understanding, appreciation, reasoning and expressing a choice.

Assessment of decision-making abilities to consent to treatment before and after standard and experimental educational intervention.

Subjects scored well both before and after both standard and experimental interventions and both educational interventions increased scores somewhat.

HDRS

A subgroup of patients with psychotic symptoms (n = 11) scored lower on the appreciation subscale compared with the nonpsychotic group (p < 0.001). The lowest appreciation score was 2 (scale range 0-4) indicating that no subject scored less than the mid-point of the scale.

Mean =30.35 and 31.30. Range 21.0- 47.0 and 14.0 -42.0. (These apply to the standard and experimental intervention groups respectively).

Owen et al. (2008)[2]

67 psychiatric inpatients

ICD-10 depression (Severity not reported)

Treatment participation

Structured clinical judgment using the MacCAT-T.

Determine prevalence of DMC for treatment in psychiatric inpatients with depression.

31% lacked DMC for treatment (medication or hospital care) - 95% CI 20-44.

Owen et al. (2009)[23]

64 psychiatric inpatients

ICD-10 non-psychotic disorders Depression =46 Post Traumatic Stress Disorder = 3 Personality disorder = 15 (Severity not reported).

Treatment participation

Structured clinical judgment using the MacCAT-T.

To investigate clinical associations with DMC in depressed patients.

Insight in non-psychotic disorders like depression (as opposed to psychotic disorders like schizophrenia, mania) was a poor “test” of DMC.

Insight measured using the SAI-E

ROC analysis gave an AUC of 0.86. Sensitivity 1.00, specificity 0.44.

Depressed mood using the BPRS

Severity of depressed mood associated with DMC with large effect size (Hedges’ g 1.25; 95% CI 0.64--‒1.85).

Owen et al. (2011)[24]

Mixed group of psychiatric inpatients

ICD-10 Schizophrenia and related disorders = 40 Depression = 16 (Severity not reported).

Treatment participation

Structured clinical judgment using the MacCAT-T.

To investigate the association between depression and regaining DMC following 1 month of inpatient psychiatric treatment.

Compared with schizophrenia and related disorders depression was associated with a higher chance of regaining DMC for treatment (OR 5.35, 95% CI 1.47–9.55).

Vollman et al. (2003)[25]

35 psychiatric inpatients

ICD-10 Moderate/Severe Depression HDRS: Mean = 21.8.

Treatment participation

MacCAT-T scores on understanding, appreciation and reasoning.

To investigate the competence of patients with depression to make treatment decisions.

Most subjects scored well on all abilities. Appreciation was most impaired ability. Subjects with scores indicating impairment in: understanding n = 5, (5.4%); appreciation n = 11 (12.0%); reasoning n = 7 (7.6%).

Unstructured physician Judgment

Compound measures: understanding and/or appreciation n = 17 (18.5%); understanding and/or reasoning n = 11 (12.0%); appreciation and/or reasoning n = 17 (18.5%); understanding, appreciation and/or reasoning n = 22 (23.9%).

One patient with depression (2.9%) was categorized by the physician as unable to give consent for drug therapy.