withdraw from the research setting at any time, issues
of confidentiality, and any other pertinent information
such as how to contact the main investigator.
The final element required to obtain informed con-
sent is competency, which refers to the functional
capacity to give valid consent to participate in research.
Grisso and Appelbaum note that those persons who
cannot use the disclosed information because of a lack
of certain cognitive abilities are not capable of partici-
pating in an informed consent procedure. When the
impairment reaches a certain level of severity, a deter-
mination can be made of incompetence. In legal terms,
a de facto incompetence determination is made when
inquiries into the person’s actual capacities reveal a suf-
ficient lack in cognitive functionality.
When making a judgment about one’s decision-
making capacities, three types of information are usu-
ally required as delineated by Grisso and Appelbaum:
(1) the person’s clinical condition, (2) the person’s
degree of functioning in tasks involving decision-
making abilities, and (3) the situation-specific demands.
There are four legal standards for assessing decision-
making competence, which include the ability to com-
municate a choice, the ability to understand relevant
information, the ability to appreciate the circumstances
and likely outcome, and the ability to rationally manip-
ulate the information. Grisso and Appelbaum also note
that although four standards have been proposed, not
all courts and jurisdictions apply all concepts in a
determination of competency. Also of importance is
that a person’s status on the four abilities is not all-or-
none. A person usually possesses all the abilities but in
varying degrees and one must consider the complexity
of the decision being made in relation to the condition
of the person making that decision.
For researchers it is important to provide all the
necessary information to the potential participant so
that he or she is able to make an informed decision.
The information of the purposes, procedures, benefits,
risks, and voluntary nature of participation must be
outlined in a written document and signed by both
parties. It is the responsibility of the researcher to
ensure that the participant understands the informa-
tion and is not being coerced in any way to participate.Competency of Special Populations
When conducting research with normal healthy pop-
ulations, researchers tend to presume that the partici-
pant is capable of understanding the material in theinformed consent document and capable of making
an autonomous decision of whether to participate or
not. However, when conducting research with poten-
tially vulnerable populations, the same assumption
cannot necessarily be made. Potentially vulnerable
populations include children and adolescents, who
are vulnerable because of their developmental level
and their susceptibility to coercion; prisoners and
other institutionalized individuals by virtue of their
lack of voluntary status; medical patients who may
have impaired cognitive function ranging from being
comatose to some memory impairment; and psychi-
atric patients as a result of possible compromised
capacity to consent. Several empirical studies have
examined the ability of psychiatric patients to pro-
vide informed consent; a brief summary of the find-
ings follows. In persons with schizophrenia and
psychotic disorders, mixed results have been pro-
duced. The consensus is that these types of patients,
on the whole, perform more poorly than their non-ill
counterparts on tests of competency. Several studies,
however, have further noted that even with this
divide, there is much heterogeneity among the schiz-
ophrenic patients and many are able to perform at a
level similar to non-ill persons. Research on persons
with affective disorders is somewhat more promising,
with this group performing at a level similar to non-
ill persons in most of the published studies. Finally,
elderly patients with Alzheimer’s disease seem to be
the population at the greatest risk for having impaired
levels of cognitive processing and thus a diminished
ability to provide informed consent.Elizabeth Arias and Barbara StanleySee also Capacity to Consent to Treatment; Capacity to
Consent to Treatment Instrument (CCTI); MacArthur
Competence Assessment Tool for Clinical Research
(MacCAT–CR)Further Readings
Appelbaum, P., Lidz, C., & Meisel, A. (1987). Informed
consent.New York: Oxford University Press.
Meisel, L., & Lidz, C. (1977). Toward a model of the legal
doctrine of informed consent. American Journal of
Psychiatry, 134(3), 285–289.
Stanley, B., & Galietta, M. (2006). Informed consent in
treatment and research. In I. Weiner & A. Hess (Eds.),
The handbook of forensic psychology(3rd ed.,
pp. 211–239). Hoboken, NJ: Wiley.150 ———Consent to Clinical ResearchC-Cutler (Encyc)-45463.qxd 11/18/2007 12:41 PM Page 150