BACKGROUND/AIMSThe purpose of this within-subjects feasibility study was to determine whether two different homeopathic remedies, Nux Vomica (NV) and Coffea Cruda (CC), exert effects on subjective mood ratings in healthy adults with a history of coffee-induced insomnia. The impact of individual personality traits, anxiety sensitivity or Type A cynical hostility, and homeopathic constitutional type (HTYPE-NV, HTYPE-CC), on remedy effects was examined to evaluate differential responsivity, in accord with clinical claims.SUBJECTS AND METHODSYoung adults of both sexes (ages 18-31) with above-average scores on standardized personality scales for either cynical hostility or anxiety sensitivity, and a history of coffee-induced insomnia, participated in the month-long study. At-home polysomnographic recordings were obtained on successive pairs of nights once per week for a total of 8 recordings (nights 1, 2, 8, 9, 15, 16, 22, 23). Subjects (N = 59) received placebo pellets on night 8 (single-blind) and verum pellets in 30c doses of one of two homeopathic remedies, NV or CC, on night 22 (doubleblind). Subjects completed the Profile of Mood States Scales at bedtime.RESULTSThe remedies produced differential effects on anger and overall mood, with improved mood following CC administration. A similar trend for depression was observed. Anxiety sensitive subjects experienced less tension following CC, whereas hostile subjects receiving CC became more tense. The high HTYPE-CC receiving CC experienced less vigor. The high HTYPE-CC receiving NV experienced more vigor.