The treatments we are investigating include bright light therapy upon awakening, and two contrasting treatments during the final hours of sleep: negative air ionization (provided at two levels) and dawn simulation (also at two levels), both switched on by a silent electronic timer or microprocessor. We hypothesize that the reduced outdoor light availability in winter, as well as reduced concentration of negative ions in the air circulation are both factors that contribute to depression. By supplementing the indoor environment with either ions or light, we are aiming to recreate summer-like conditions that are therapeutic. Our past studies have shown all three methods to have antidepressant effects in patients with seasonal affective disorder (SAD). Unlike light therapy, negative air ionization is imperceptible (you cannot sense when the ionizer is active).