SSRI Response Best for Patients with Late Sleep Cycles

Determining which patients will respond best to major depressive disorder drug therapies may be possible using a 24-hour wristband monitor, according to the results of a study published in the Journal of Psychiatric Research.

Researchers from the Medical College of Georgia at Georgia Regents University monitored 58 medication free adults with major depressive disorder for nine weeks in order to determine which patients would respond best to treatments like Prozac. The patients underwent a week long process to collect actigraphic data before the trial, which included fluoxetine in combination with either eszopiclone or placebo. The wristband aimed to identify the patients referred to as “night owls,” as those patients tended to be the best responders to selective serotonin reuptake inhibitors (SSRIs).

“What our findings suggest is that night owls, the group most likely to be depressed, also look like the patients who are most likely to respond,” lead researcher W. Vaughn McCall, in a press release. “The larks are more likely to need two drugs.”

The researchers found that the night owls were most likely to respond to SSRIs, a finding they attribute to the patients’ abilities to shift to a more usual, middle of the night time frame. Similarly, those who were not night owls may respond better to drugs like bupropion — drugs that target the neurotransmitter dopamine to provide a stimulation that can readjust their lowest activity times from deep sleep times to slightly later in the day, the researchers speculate.

“We all tend to be morning people or not, and environmental factors, such as work schedules, can also push us in one direction or another," McCall continued.

The rest cycle can be shifted later in the 24 hour day by excessive exposure to light, especially in the evening hours: it can come from a lamp, television, or touch screen tablet. It seemed to the researchers that the patients with the periods of latest rest, near 5 am, had the best response to SSRIs.

Even though the study population was small and the findings are preliminary, the researchers believe that the results can influence how doctors chose medications for their patients.

“You only hit a home run first at bat about one third of the time; two-thirds of the time you have failed, struck out," said McCall.”

McCall is pursuing federal funding for a similar, but larger study on the subject. The investigative team called this study “a place to start.”