A total of 70 outpatients with alcohol use disorder and BPD, cyclothymic disorder, schizoaffective disorder (bipolar type), or MDD with mixed features will be enrolled in a 12-week, randomized, double-blind, parallel-group, placebo-controlled study of ondansetron. Participant will receive either ondansetron or a placebo for 12 weeks. He or she has an equal chance of receiving ondansetron or placebo.~Randomization will be stratified based on > 4 or ≤ 4 drinking days per week at start of the study. Ondansetron or placebo will be given at 0.5 milligrams twice a day for the first 4 weeks. At weeks 4, 8 and 10 the dose may be increased to 1.0, 2.0 or 4.0 milligrams twice a day, respectively, if significant reductions in depression and alcohol use are not observed and the participant is not experiencing any side effects. Blood will be drawn for routine laboratory analyses including a complete blood count (CBC), liver panel, and Carbohydrate-deficient Transferrin (CDT) at baseline and weeks 4, 8 and 12.~Each participant will return for weekly follow-up visits and repeat outcome measures. Pill counts will be conducted, and a list of current medications and doses will be recorded at each visit. Participants will be compensated at each appointment with a bus pass, gift cards, and a monetary incentive for compliance. Participants will be evaluated by both the research assistant (RA) and principal investigator (PI) at each visit.~The Hamilton Rating Scale for Depression (HAMD) and Timeline Followback (TLFB) will be given at each visit as the primary outcome measures. Cognitive assessments will be performed at baseline and week 12.
The purpose of the study is to determine if ondansetron, as an add-on therapy, is associated with reduced depressive symptoms and alcohol use in outpatients with bipolar disorder (BPD), cyclothymic disorder, schizoaffective disorder (bipolar type) and major depressive disorder (MDD) with mixed features. The investigators will also use blood samples to determine if the genotype for the serotonin transporter gene is associated with response to ondansetron.