Stimulant Enhancement of Well-Being Therapy for Depression

This study aims to identify a novel enhancement strategy for residual symptoms of major depressive disorder (MDD) Dopamine (DA) has been viewed as a "pleasure neurotransmitter" for over 30 years. Yet recent data from animal and human studies suggest that dopamine has greater effects on "wanting" than on "liking." Therefore, the investigators of this study have hypothesized that amphetamine/d-amphetamine (AMPH), a medication which increases dopamine transmission in the reward centers of the brain, may have a more powerful antidepressant effect in combination with well-being therapy (WBT), a specific type of cognitive-behavioral therapy, which helps individuals with depression to increase their contact with natural rewards and decrease reward-interfering thoughts. The investigators will test their hypothesis by randomizing 40 individuals with residual symptoms of depression, already taking an antidepressant that affects serotonin (e.g. Prozac, Paxil), to 8 weeks of treatment with either WBT in combination with AMPH, or WBT with pill placebo. The effectiveness of each treatment will be measured using a reliable scale, called the Hamilton Depression Rating Scale. The investigators have also hypothesized that people assigned to the stimulant/WBT group will have greater improvements in functioning, well-being, and positive affectivity than those the people assigned to the WBT/placebo group.