The majority of patients (83.3%) demonstrated at least one error during the DMC interview (MacCAT-CR). The most common source of errors by far was difficulty recalling aspects of the study information disclosed during the Understanding subscale (65.5% of patients). Further evidence of the importance of memory processes and/or systems in DMC among schizophrenia patients is provided by Eyler et al.20
. Using functional magnetic resonance imaging, these authors found that patients’ performance on the MacCAT-CR Understanding subscale was correlated with brain activation during a verbal learning task in regions known to support learning and memory including the right hippocampus and bilateral parahippocampus. Together, these findings suggest that efforts to enhance the research consent process for patients with schizophrenia and schizoaffective disorder should focus on factors that facilitate initial acquisition and processing of the disclosed information. Indeed, in the present study, patients struggled to recall even the most basic points of the study information (e.g., 42.9% had difficulty recalling the purpose of the study). It may be that the large amount of detailed information provided during consent procedures, in combination with patients’ impaired memory abilities, makes it difficult for them to learn and retain the key points. Our findings do suggest, however, that repetition of the study information ameliorates recall errors in most cases. Together, these findings highlight the importance of structuring the disclosed study information in such a way as to emphasize key points and repeating the information in order to facilitate recall.
Patients’ responses were also notable for the errors they did not
make. Ethical concerns have been raised surrounding the notion that psychotic symptoms per se
(e.g., delusional thinking) might impede DMC. However, in the present analyses, there was no evidence to support detrimental effects of psychosis on DMC for research participation among this outpatient sample. These findings complement quantitative studies that found no relationship between DMC for research participation and the positive symptoms of schizophrenia in samples of outpatients and/or inpatients21
. However, some quantitative studies have found a negative relationship between positive symptoms and DMC, including a study of DMC for research22
and a study of DMC for treatment23
, both of which were of inpatient samples. On average, individuals in our sample were rated as having mild psychiatric symptoms, although some patients did have moderate symptoms. On the PANSS, 28% of the sample was rated as having delusional symptoms of at least moderate severity and 35.4% of the sample was rated as having hallucinatory symptoms of at least moderate severity. Thus, despite psychotic symptoms of this severity being present among our sample, they were not evident during patients’ responses on the MacCAT-CR, suggesting that these symptoms did not affect DMC. Nevertheless, conclusions regarding the impact (or lack thereof) of psychotic symptoms on DMC must be tempered as our sample consisted primarily of clinically stable outpatients. A limitation of the present study is that results cannot be generalized to more acutely ill or inpatient populations. Future research should explore whether inpatients exhibit a different pattern of DMC-related errors.
Despite concerns regarding the potential for coercion in this population, the fact that the vast majority of patients in the present study recognized the voluntary nature of participation suggests that perceived coercion is uncommon. Minimal previous work has examined the possibility of coercion in research enrollment in mentally ill populations. Moser and colleagues assessed susceptibility to coercion in the research context among 30 incarcerated mentally ill people (of whom 5 had schizophrenia or schizophrenia-related disorders). Although patients with worse neuropsychological functioning showed higher susceptibility to coercion, no evidence of actual coercion was found24
. Despite these null findings, there remains the possibility of undue influence and therapeutic misconception (of which one aspect may be conflating the role of the clinician and researcher—particularly if that happens to be the same individual)25
In the present analyses, patients were observed as making more errors during the Understanding subscale than during the remaining MacCAT-CR subscales. This finding may be counterintuitive in that adequate appreciation and reasoning abilities would logically seem to be dependent upon good understanding of the study information. However, we suspect that this finding is an artifact driven by the nature of the MacCAT-CR in that the Appreciation and Reasoning subscales contain far fewer items than the Understanding subscale. Thus, those subscales are likely less sensitive in eliciting patient error.
In interpreting our results, it is important to remember that participants’ incorrect responses were classified according to the apparent
source of the error and that we cannot be certain of the true
source of the error. For example, errors classified as “difficulty recalling” could be due to difficulty encoding, storing, or retrieving the information. Alternatively, this type of error may have resulted from a number of other intrapersonal or contextual factors26
. Personal limitations such as poor attention, low motivation, or fatigue may have affected an individual’s responses, as may have situational demands, such as being presented information that was too complex or being presented information in a manner unconducive to memory. Furthermore, deficits in pragmatic or social communication27
may have contributed to difficulties understanding the questioners’ intent or responding appropriately.
It is also important to recognize that, in the context of the present study, decisional capacity was assessed in reference to consent for an outpatient naturalistic study of the short- and long-term side effects of FDA-approved antipsychotic medications. Contrast this context with that of a placebo controlled clinical trial conducted in an acute inpatient psychiatry setting, and/or in the context of capacity to competently refuse treatment among acutely psychotic persons (e.g., refusal of hospitalization or medication). Clearly, the association between capacity and psychopathology may differ across these different contexts. Moreover, the considerations of respect for autonomy versus protection of those with diminished capacity for authentic autonomous decision making may be more complex, or at minimum, distinct. Thus, the types of errors, and the source of errors seen in the present sample may not readily generalize (either in terms of statistical association or ethical implications) to distinctly different contexts.
This study has additional limitations. As the protocol was not originally designed for a qualitative examination of the data, some errors may reflect interviewer (rather than patient) error—e.g., failing to record a patient’s response verbatim. The way we evaluated the MacCAT-CRs also introduced limitations. First, a degree of subjectivity is inherent in how raters classified patients’ responses, which likely impacted the initial interrater agreement rates () prior to the final codes being determined by group consensus. Subjectivity may affect interrater reliability28
, which itself puts an upper limit on validity29
. However, common procedures to improve apparent objectivity (such as more structured response formats) do not necessarily improve reliability30
, and even perfectly reliable measures may lack validity29
. The bottom line is that the ideal (most reliable and valid) method of classifying respondent errors during capacity assessment is not presently known. The present study illustrates one potential approach, but additional research on error types would be useful in developing and evaluating other potential methods which could be more routinely applied in determining where subjects in a given study or population are most likely to have difficulty with routine consent procedures. A second limitation is that some MacCAT-CRs were evaluated more than once during the coding scheme development process, in order to refine our coding methods. Third, although we feel that our group decisions represent a more accurate depiction of patients’ responses, rating each MacCAT-CR via group consensus limited individual raters’ independence. Finally, there are several known limitations to the MacCAT-CR measure itself31
, limiting, to some degree, the validity of our codes. As mentioned above, the Appreciation and Reasoning subscales contain few items, constraining the amount of information that was elicited from patients and making comprehensive evaluation of their appreciation and reasoning abilities difficult.
Nevertheless, these results inform ways to improve consent procedures to increase the likelihood that patients with schizophrenia are making informed decisions regarding research participation. Given patients’ recall difficulties, key study information should be highlighted and repeated during consent procedures, while some information may require less explanation. For example, in the present sample, the vast majority of patients recognized that participation would be voluntary, but a significant proportion had difficulty recalling the purpose of the study. This suggests that spending a great amount of time covering voluntariness is unnecessary, while additional explanation of other key points is warranted.
The finding that some patients provided rationales for participation that were considered overly vague or otherwise limited in content suggests that some patients have difficulty verbalizing their reasons. Alternatively, such lack of clear response may be due to limitations in the Reasoning subscale. As probing may be required to obtain adequate information from patients about their decision-making process and reasons, consent procedures should include an interactive discussion of patients’ reasons for and against participation. This would have the additional salutary effect of providing researchers the opportunity to clarify or re-explain aspects of the study, should patients’ reasoning seem faulty or vague.
Researchers should be aware that potential participants may confuse the goals and purposes of research and clinical care32
. In the present study, some patients did have difficulty appreciating the differences between the two or overemphasized how being in the study might benefit them personally. However, they were being asked to consider consenting to a minimal-risk study that could actually have some benefit for them (e.g., they would receive comprehensive evaluations), so therapeutic misconception is not as concerning in this situation. Future studies should continue to evaluate the nature and prevalence of therapeutic misunderstanding in higher-risk studies, like randomized placebo-controlled clinical trials. Qualitative analysis of patients’ responses during DMC assessment within such contexts could elucidate points of confusion for patients and suggest ways to improve consent procedures to reduce therapeutic misconception. For all studies—but higher-risk protocols in particular—consent procedures should emphasize the differences between research and clinical care. Again, an interactive discussion would help the researcher understand patients’ beliefs and address any misconceptions.
Interventions designed to improve DMC have yielded promising, but mixed, results33
. Consideration of the errors that patients make during DMC processes, as suggested by the present study, may inform the development of more targeted interventions. Modifications to consent procedures that should be evaluated in future studies include emphasis and repetition of key study information, clarification and emphasis of distinctions between research and clinical care, and expanded discussion and assessment of patients’ abilities to appreciate and reason about the presented information. Finally, consistent with ethical obligations of researchers to ensure that participants have understood the relevant information, the consent process should be viewed as a conversation and information sharing process, rather than merely the reading and signing of the consent form by potential participants34
Knowledge of the types of errors that individuals make during decision-making for research participation may also help IRBs to provide further guidance to researchers regarding the informed consent process. IRBs aptly regulate what study information is disclosed to potential participants but typically give less attention to how that information is conveyed. As described above, our results point out some weaknesses in the informed consent process, at least for this particular population of clinically-stable outpatients with schizophrenia, and suggest possible strategies for improvement. IRBs could use this information to encourage researchers to employ more novel and interactive methods of information disclosure.