Interdisciplinary collaboration in mental health services has recently flourished, mostly due to the changes that have taken place during the past 50 years in the delivery of such services. This chapter presents the benefits of collaboration between a psychologist and a psychiatrist, and discussed through a case study. A young man exhibiting both positive and negative psychotic symptoms was treated with psychotherapy and pharmacotherapy by a psychologist and a psychiatrist. The psychologist referred Erophilos for medication evaluation to a prescribing psychiatrist with whom he already had a mutually respectful working relationship and shared philosophies of treatment. Since the behaviour of every person is always influenced by cultural as well as biological and psychological perspectives, mental health professionals need to focus on the cultural dimensions of illness behaviour. The two mental health professionals respected each other’s work and shared the belief that both pharmacotherapy and psychotherapy were crucial and necessary for the client’s recovery.