Our research group has 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 targets specific serotonergic nuclei in the raphe. In animal models, these nuclei have been shown 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.
In addition to impacting depressive symptoms and body temperature, The investigators have observed that WBH induces striking increases in prosocial and self-disclosing behavior in many individuals. This effect initiates in the heating phase of the treatment and culminates at maximum body temperature. Importantly, our observations thus far suggest that this prosociality only occurs when the person in the hyperthermia box is accompanied by someone he/she knows to at least some degree. For example, a recent subject was silent during his initial WBH treatment in which he was attended by one of our staff that he had never met. He elected to get a repeat WBH session. The same "attendant" was present for this second WBH session, and during this session the patient became strikingly talkative and without prompting self-disclosed a range of very intimate personal issues related to his depression, such as a previously undisclosed history of childhood sexual abuse.
The goal of the current proposal is to conduct a pilot study to evaluate whether this observed prosocial effect of WBH might be employed to accelerate and deepen the formation of therapeutic alliance in patients undergoing an 8-12 session course of cognitive behavioral psychotherapy (CBT). Our study design will also more rigorously test our clinical observation about the prosocial effects of WBH. In addition to potentially enhancing psychotherapeutic outcomes, the current study may provide data relevant to larger issues related to the near universal use of hyperthermia in indigenous cultures around the world for spiritual and health purposes.
