As a psychologist, you conduct scientific studies to diagnose mental health problems. While you don't administer medication, you use various therapies to minimise behavioural issues. A psychiatrist specialises in the medical field devoted to the diagnosis, prevention, and treatment of mental disorders. A psychiatrist is a medical doctor (M.D. or D.O.) who specialises in mental health, including substance use disorders. Their job is to apply pharmacological remedies to psychological diagnoses. Since they are trained in psychology, they can diagnose, prescribe, administer medicines and create treatment plans for patients.