The case of Osheroff v. Chestnut Lodge focused attention on the relationship between pharmacotherapy and dynamic psychotherapy in the treatment of mood disorders. The author presents a group of representative case vignettes under the headings: the impact of pharmacotherapy on the psychotherapist's attitude and technique, the effect of pharmacotherapy on psychotherapy, the impact of pharmacotherapy on the patient, and the decision to combine modalities. He concludes that multimodal treatment is increasingly becoming the norm. The evaluating clinician needs to accept the burden of documenting the decision to include or to omit medication in a great many cases. It is important to use medication and psychotherapy in an informed and systematic fashion, rather than introducing either only after the other fails. Medication may be prescribed by the psychotherapist or by a different treater. In the latter case, each clinician must understand the basic principles of