May 26, 2010 (New Orleans) -- Simply spending more time with the doctor may help people with depression feel better.
Patients on placebo experienced substantial improvements in mood as the number of tests given at each visit increased, says study researcher Jeff Musgnung, MT, MS, of Pfizer Inc.
About 30% of patients on placebo who were given one screening test per visit showed mood improvements on a commonly used scale known as the Hamilton Depression Rating Scale.
In contrast, about 42% of patients on placebo improved when given four assessments per visit.
"Our theory is that as depressed patients spend more time with the doctors and other health care staff, they may experience what is known as the placebo response," Musgnung tells WebMD.
Among people taking Effexor in the study, however, there was no association between number of visits and response rates.
The results came as no surprise to Adelina Alcorta, MD, head of the department of psychiatry at Autonomous University of Neuvo Leon, Mexico.
"Sometimes people feel better if you just pay extra attention to them," she tells WebMD. "It's good for the patient, but bad for clinical trials."
That's because as more people on placebo improve, it becomes more difficult to show that a drug is better than placebo in any given trial, Musgnung explains.
The findings come at a time when the number of assessments and the length of patient visits are increasing in clinical trials, he says.
At the start of the Effexor trials in 1986, patients got an average of three or four assessments per visit. By 2006, that increased to eight or nine assessments, Musgnung says.
This placebo effect is something that needs to be taken into account when designing clinical trials, says Donald Hilty, MD, co-chair of the committee that chose which studies to highlight at the meeting and professor of psychiatry at the University of California, Davis.
The study was funded by Pfizer, formerly Wyeth Research, which sponsored the Effexor trials.
This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.