Schizophrenia May Not Impair Decision-Making Ability

Whether schizophrenia patients are competent at making decisions regarding their own treatment is a question that comes up frequently in clinical practice, but not a lot of research has been conducted on it.

To try to answer that question, four psychiatric researchers decided to undertake a study: Barton Palmer, Ph.D., an assistant professor of psychiatry at the University of California at San Diego (UCSD); Laura Dunn, M.D., an assistant professor of psychiatry at UCSD; former APA president Paul Appelbaum, M.D.; and Dilip Jeste, M.D., a professor of psychiatry and neuroscience at UCSD. They received funding from the National Institute of Mental Health and the National Alliance for Research on Schizophrenia and Depression.

The study included 59 subjects with schizophrenia or schizoaffective disorder aged 40 or older who were stabilized on antipsychotic medications and living in the community, as well as 38 mentally healthy comparison subjects. The researchers used an instrument called the MacArthur Competence Assessment Tool for Treatment (MacCAT-T) to assess the subjects’ ability to make treatment-related decisions. The MacCAT-T subscales evaluate the ability to comprehend disclosed information regarding the condition and proposed treatment; to appreciate the significance of the disclosed information for one’s own condition; to compare the risks and benefits of treatment options and the likely consequences of one’s choice; and to arrive at and communicate a choice regarding the proposed treatment. The subjects were also evaluated for psychiatric symptoms and neuropsychological functioning.

Data Show Marked Variations

The researchers then compared the treatment-related decision-making capacity of the schizophrenia subjects with that of the control subjects. They found that the schizophrenia subjects’ capacity was generally not as good as that of control subjects, yet some schizophrenia subjects demonstrated remarkably good capacity.

The scientists also used their data to determine why schizophrenia subjects were generally not as good at treatment-related decision making as the controls were. While they did not find any significant links between MacCAT-T scores and psychiatric symptoms, they did find significant links between MacCAT-T scores and cognitive test scores.

“Thus, differences in capacity appeared more related to cognitive functions than to severity of psychopathology,” they concluded in their study report, which was published in the March Archives of General Psychiatry.

These findings have some important implications for clinical psychiatrists. For example, Appelbaum told Psychiatric News, “The variation in performance in this severely ill population—including many patients who performed quite well—implies that we cannot assume that because of a psychotic illness, a patient is necessarily incapable of making decisions about treatment. Individual consideration, though not always formal assessment, of patients’ decisional capacities is called for. . . . [Also,] the relationship with neurocognitive impairment suggests that we might do well looking at many currently incompetent patients as having something akin to a learning disorder. It may not be that they can’t understand, appreciate, and reason sufficiently to make decisions, but simply that they need more support (for example, time, repetition, information presented in multiple modalities) to do so. . . .”

“For clinical psychiatrists,” Jeste told Psychiatric News,” the most important finding may be the presence of considerable heterogeneity in decisional capacity among older outpatients with schizophrenia. It is thus inaccurate either to assume that all people with schizophrenia lack sufficient decisional capacity to participate in their treatment decisions or alternatively to assume that ritualistic disclosure (in a ‘one-size-fits-all’ format) of medication benefits and risks (including side effects) is sufficient for all patients. The best predictor of the patients’ decisional capacity is the degree of their cognitive impairment and not their age or the level of their psychopathology. . . .”

Results Similar to Prior Study

Also noteworthy, similar results have been obtained in a previous study regarding the research-participation decision-making capacity of schizophrenia subjects. In that study, Appelbaum; William Carpenter Jr., M.D., director of the Maryland Psychiatric Research Center; and colleagues used an instrument called the MacArthur Competence Assessment Tool-Clinical Research (MacCAT-CR) to assess the capacity of 30 schizophrenia or schizoaffective disorder subjects, as well as the capacity of 24 mentally healthy subjects, to decide whether to participate in research. Some of the subjects with schizophrenia or schizoaffective disorder were inpatients, others resided in the community, but all were receiving antipsychotic medications during participation in the study.

The capacity of the schizophrenia and schizoaffective disorder subjects was generally not as good as that of the controls, the scientists reported in the June 2000 Archives of General Psychiatry. The reason appeared to be essentially cognitive defects, not psychotic symptoms.

Still more research on schizophrenia patients’ treatment-related decision-making capacity and research-participation decision-making capacity is in the works. For instance, Appelbaum said, “I am collaborating with several groups around the country, including the UCSD group, in ongoing studies of ways in which the informed-consent process can be improved to help patients with some degree of impairment make decisions for themselves.”

Dunn added, “We are also interested in developing user-friendly instruments for screening potential research participants for possible impairments in decisional capacity. The overarching theme of our research is to find ways to protect and enhance the autonomy of research participants whenever possible since. . . a psychiatric diagnosis, in and of itself, by no means implies that a person has impaired decision-making capacity. . . .”

And how competent are schizophrenia patients who have not yet been placed on antipsychotics to make treatment decisions? “I am not aware of any published studies of first-break premedicated patients,” Jeste said, “but clearly that is an important area for research as decisional-capacity questions often arise in acute psychiatric ER settings.”

An abstract of “Correlates of Treatment-Related Decision-Making Capacity Among Middle-Aged and Older Patients With Schizophrenia” is posted online at http://archpsyc.ama-assn.org/cgi/content/abstract/61/3/230. ▪

Arch Gen Psychiatry 2004 61 230