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Psychiatry Newsletter - Staying the (Vaccine) Course

Hopkins Brain Wise Summer 2010

Staying the (Vaccine) Course

By: Marjorie Centofanti
Date: July 10, 2010

Vaccine needle

For want of a nail, the shoe was lost. Shakespeare went to great lengths to show the need for attention to detail—finally it’s a kingdom gone, thanks to a lame horse. 

But the researchers testing an anti-cocaine vaccine are well aware of details that, ignored, could derail their trials. High on the list is compliance. Asking cocaine-dependent subjects to come for two weeks of screening, then monthly visits including tests and injections and then a follow up two weeks later—is a lot, even if they appear highly motivated.

“Asking anyone for that sort of compliance is a lot,” says addictions researcher Maxine Stitzer. She’s one of a national cadre of experts in motivation and contingency management—a field she describes as “providing incentives to help people adhere to regimens that are good for them.”  Stitzer’s advisement has figured prominently in the study.

“Compliance is a broad, common problem in medicine,” she says, whether it’s taking a full course of antibiotics or keeping a symptom log. People in drug abuse programs aren’t an exception.

So well before start of the multisite trials, Stitzer and colleagues knew preliminary research was in order. They simulated the cocaine-vaccine trial using a different vaccine that participants needed—one for hepatitis B. 

For some in the study, the researchers offered an encouragement common in addictions treatment—in this case, a “draw bowl” containing 500 tickets, half exchangeable for prizes or gift cards. Others were simply asked to stay the course. The result? A full three-quarters of those with access to the bowl received all their scheduled injections. For the comparison group, it was less than half. Stitzer was especially surprised as the differences opened up later in the 6-month program when motivation starts to flag.

Incentive programs aren’t whimsical. They take a fair amount of forethought. “They’re also consistent with principles of behaviorism,” Stitzer adds, “and could play a significant part in keeping people coming long enough to finish a course of vaccines.”