Depression can affect patient's understanding of informed consent

Frequent repetition of consent information can help bolster patients' ability to give consent

Patients hospitalized with depression may need extra help understanding the informed consent process for research, due to cognitive impairments that affect their ability to understand information being given to them about a study.

That's one finding from a study of 31 inpatients with depression recruited from a hospital psychiatric unit. The group took a battery of tests that measured various indicators related to decision-making.

The tests revealed that 15 of the participants (48 percent) had at least mildly impaired neurocognitive function. Results were published in a recent issue of the journal Psychiatry Research.

The study also had subjects listen to information about a fictional informed consent disclosure for a drug trial and tested them on their understanding of the information. Those indentified as impaired had correspondingly lower scores than the unimpaired inpatients and a control group.

"(The study) shows that inpatients are more vulnerable, not only to cognitive impairments, but corresponding with those impairments, they are also more vulnerable to decision-making problems," says Michael Basso, PhD, ABPP-CN, a neuropsychologist, director of clinical training and associate professor of psychology at the University of Tulsa, OK.

Basso says literature over the past 15 years has shown this cognitive impairment occurs in a significant subset of depressive patients. But he says the issue hasn't received wide attention in research circles.

"I think as people come to realize that some people with depression have considerable cognitive impairment associated with the illness, they will recognize that this is a potentially vulnerable population," he says. "I don't think there's a lot of attention given to it right now."

Cueing, repetition help

In addition to identifying deficits in some of the inpatients studied, Basso's group also looked at different ways of bolstering their ability to understand and remember informed consent disclosures. They tested three different methods of relaying information to the patients:

– Reading the informed consent aloud to the participant, without interruptions, while the participant follows along with his or her own copy;

– Reading the consent aloud in small successive steps, with pauses to ask questions of the participant. If they fail to demonstrate understanding, they're asked more specific questions;

– Providing the information in small steps, with frequent cueing and repetition of the details.

With each group – the control group, unimpaired inpatients and impaired inpatients – the uninterrupted disclosure produced the lowest scores of understanding, while repetition and cueing produced the highest scores. Basso suggests that providing repetition and cueing in the informed consent disclosure might be a way to compensate for the cognitive problems experienced by some inpatient depressives while still allowing them to participate in research.

"You could try to mitigate the weaknesses by using repetition and cueing and then re-evaluate the person, to see if they're continuing to display significant compromise," Basso says. "If they are, then it may be worthwhile to look at obtaining a proxy to provide consent – a family member or close friend, who's got some sort of official representation authority such as a health care power of attorney."

Basso stresses the people identified as having this cognitive weakness had more severe forms of depression. He says studies of outpatients with depression have shown that only a very small minority have any kind of reasoning or decision-making problems.

And he says that even impaired patients still may be capable of making a decision to participate in research.

"Just because somebody has an illness or syndrome that is associated with compromised mental status, it doesn't mean there's decisional incapacity," Basso says. "Even among schizophrenics or people with Alzheimer's disease, (research has) shown that a significant number of those people are capable of giving informed consent."

IRB mindfulness

He suggests that IRBs should be mindful of this potential vulnerability when presented with a study that looks at inpatient depressives.

"Without wanting to put an undue burden on the researchers, I think it would be prudent to implement some means of determining whether the patient has neuropsychological impairment," Basso says. "If so, such a patient would be worthy of more careful scrutiny as far as their capacity to consent."

Basso says he himself has had little difficulty getting his research approved by IRBs – in part because he only does minimal risk research. But he also believes that IRBs may fail to recognize the potential decision-making difficulties that severely depressed patients may have.

He says there's a need for more research into other aspects of decision-making that may be compromised by depression – the willingness of patients to take risks, for example, their ability to express a choice or their potential for therapeutic misconception.

Basso also is looking at other groups that might benefit from the repetition and cueing approach to informed consent, including patients with multiple sclerosis who have cognitive impairment. He published another study last year that showed similar improvements in understanding using the repetition and cueing approach.

Reference

Ghormley C, Basso M, Candlis P, et al. Neuropsychological impairment corresponds with poor understanding of informed consent disclosures in persons diagnosed with major depression. Psychiatry Res 2010 Nov 30 (Epub).