This chapter, written for undergraduate medical students and post-graduate doctors in training, presents information on how to manage unusual behaviour — a case which they are likely to encounter in the future in a general practice setting. It presents the case of a 22 years old man who has moderately severe schizophrenia and also experiences unusual behaviour. His life has been punctuated by admissions to the psychiatric unit, but provided that he continues to take his daily oral anti-psychotic medication with support from you and his community mental health nurse, he remains tolerably well and cheerful. The chapter provides details of the patients' medical history and the key findings of clinical examination, together with initial investigation results data for evaluation, and helps them develop their skills of clinical reasoning. Key questions then prompt the student to evaluate the patient, and reach a decision regarding their condition and the possible treatment plan.