LAUSR

increases in temperature produced by MPD could trigger compensatory cooling mechanisms, which would explain the increased yawn frequency. Moreover, the abrupt and complete eradication of yawning after the discontinuation of MPD and introduction of atomoxetine is consistent with this interpretation. Atomoxetine does not appear to produce associated increases in brain or body temperature, and, in fact, it has been linked with hypothermia in at least one case.13 This appears to be the first documented case of MPDinduced yawning, and thus, future research should be aimed at more closely examining the connection between MPD, hyperthermia, and excessive yawning. Although further investigations are needed to support this interpretation, such research could have important clinical applications related to the recognition and treatment of cases of excessive yawning triggered by druginduced abnormalities in thermoregulation.