Integrating biologic and psychologic treatment: the need for a unitary model.

Psychiatric illness tends to be conceptualized as either a biologic or psychologic process, a dichotomy that is inevitably reflected in treatment. A unitary model encourages the psychotherapist to incorporate biologic modalities as a meaningful interaction within the therapy. The biologic therapist, in turn, can be more effective when aware that even severe mental illness is also a psychologic process. Causality cannot be inferred from severity of illness nor should it be used to rationalize a two-track approach to treatment. Biologic treatment should never be considered a treatment of last resort.