Six studies of the acute treatment of MDD have examined the efficacy of IPT either following medication treatment, as a comparator to antidepressants, or as part of combined treatment (see Table 13–1). In the first study (Klerman et al. 1974; Paykel et al. 1975), patients (N = 150) who had responded to amitriptyline (100–200 mg/day) were randomly assigned to receive 8 months of maintenance treatment with either IPT or a "nonscheduled treatment" in which patients could contact a psychiatrist whenever they felt a need for treatment. (This condition is referred to in other manuscripts as once-a-month supportive psychotherapy or low-intensity contact therapy group.) Within their therapy group assignment, patients were further randomly assigned to receive maintenance treatment with amitriptyline, placebo, or no pill, resulting in a six-cell design. Rates of relapse were similar for those receiving amitriptyline and IPT (12% vs. 16%). Patients who received both amitriptyline and IPT had better depression outcomes and better scores on a range of social adjustment measures, including overall adjustment, work performance, and communication, than those taking amitriptyline alone, suggesting an additive effect of IPT on medication treatment (Weissman et al. 1974).