The Brain on Whole Body Hyperthermia: A Neuroimaging Study

The investigators have observed in an open trial that a single session of whole body hyperthermia (WBH) induced rapid antidepressant effects that persisted for at least a week in patients with major depression (MDD) severe enough to warrant inpatient hospitalization. In addition to reducing depression, the single session of WBH induced a prolonged reduction in mean core body temperature, consistent with basic science data from our group suggesting that hyperthermia activates a skin-to-brain pathway that have been shown in animals to be important for mood and body temperature regulation. Consistent with this known anatomy in our preliminary study in depressed patients, reductions in core body temperature were highly correlated with reductions in depressive symptoms over the same time period (one week post WBH). Moreover, patients with higher mean core body temperature prior to treatment had enhanced antidepressant effects. Because increased body temperature is an outcome of poor functioning in the skin-to-brain pathway activated by WBH our data suggests that WBH may actually sensitize this pathway in ways that promote changes in brain functioning known to promote emotional well-being. The results of our first open trial have encouraged us to conduct a larger, more rigorous placebo-controlled, double blind study of WBH for MDD, which is currently underway at the University of Arizona Medical School. Missing from our assessments in this ongoing double-blind study is any measure of the impact of WBH on brain function. The current proposal addresses ths gap in our investigative portfolio by proposing to conduct a second, randomized trial of active vs. sham WBH that will examine the impact of WBH on measures of brain function known from prior studies to be important for both depression and its treatment.