Encyclopedia of Psychology and Law

subjects in a given research study. Following disclo-

sure of discrete informational elements, subjects’

understanding is queried by asking them to paraphrase

the disclosure about specific items. Appreciation ques-

tions can be modified, if necessary, according to the

nature of a given project but reasoning and choice

questions are fixed. There is no effort to provide the

kind of comprehensive disclosure typically embodied

in informed consent forms or to measure understand-

ing and appreciation of, or reasoning about, all aspects

of the study. Rather, the MacCAT–CR offers a virtual

“biopsy” of subjects’ abilities related to competence,

on the assumption that the sampled data will be typical

of their abilities in dealing with a complete disclosure.

Subjects’ responses to the MacCAT–CR items are

scored in a structured fashion, with scores aggregated

on scales for each of the four abilities being assessed.

However, composite scores across all four scales are

not generated, because poor performance on any one

of the relevant abilities may indicate significantly

impaired capacity, rendering a composite score mean-

ingless. Nor does the MacCAT–CR provide a fixed cut-

off above which subjects are deemed competent to

consent. The degree of capacity required for participa-

tion in a given study should reflect the characteristics

of that study, including its complexity and risks.

Moreover, the capacity demanded of subjects at risk for

decisional impairment (e.g., persons with mental ill-

nesses, developmental disabilities, dementia, and seri-

ous medical disorders) ought not to exceed the abilities

demonstrated by the general population. Finally, deci-

sions about capacity should take into account clinical

data that may not be reflected in assessment scores.

Although investigators or institutional review boards

can set MacCAT–CR cutoffs for particular studies, the

instrument is designed to be used as an aid to clinical

judgment, with investigators retaining the discretion to

determine whether subjects are capable of consenting.

Use of the MacCAT–CR for research on decisional

capacity and to screen subjects for entry to research

projects has demonstrated that the instrument can be

scored reliably, and that it shows good construct and

convergent validity. Studies have been performed to

date with samples of persons with depression, schizo-

phrenia and related psychotic disorders, Alzheimer’s

disease, mental retardation, and HIV infection and

with prisoners, forensic patients, and parents of

neonatal research subjects. Impairments in the abili-

ties measured by the MacCAT–CR correlate strongly

with cognitive impairments on neuropsychological

tests and correlate more variably with psychotic

symptoms. Thus, increasing levels of decisional abili-

ties are found as one moves from subjects with

Alzheimer’s disease to those with schizophrenia,

depression, and general medical illnesses. Further

research is required to determine the impairments

associated with varying levels of depression and with

medical conditions in which the disorder itself or its

treatment may affect mentation.

Screening of potential research subjects with the

MacCAT–CR has demonstrated that subjects, espe-

cially those with mental illnesses, who score poorly on

initial administration can often experience improved

decisional capacities with remedial educational efforts.

As might be expected, levels of understanding show

the greatest response to additional education, with

lesser impact seen on appreciation and reasoning.

Nonetheless, these studies have suggested that many

research subjects can learn the information required to

give a competent consent if afforded extra assistance

for doing so. Thus, screening for decisional capacity

accompanied by remedial education may result in bet-

ter informed subjects capable of giving consent on

their own rather than in the exclusion of large numbers

of subjects or in a resort to substituted consent.

Paul S. Appelbaum

See alsoConsent to Clinical Research; MacArthur

Competence Assessment Tool for Treatment Decisions

(MacCAT–T)

Further Readings

Appelbaum, P. S., & Grisso, T. (2001). MacArthur

Competence Assessment Tool for Clinical Research

(MacCAT–CR).Sarasota, FL: Professional Resource

Press.

Grisso, T., & Appelbaum, P. S. (1998). Assessing competence

to consent to treatment: A guide for physicians and other

health professionals. New York: Oxford University Press.

MACARTHUR COMPETENCE

ASSESSMENTTOOL FORCRIMINAL

ADJUDICATION(MACCAT–CA)

Mental health professionals often conduct evalua-

tions to assist courts in determining whether a criminal

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