Psychologists have studied human behavior and the brain (including how people think, feel, learn and behave) and have been trained to assist people who are having challenges coping with emotions, thoughts and actions. This can include those experiencing mental health problems such as anxiety and depression, addictive behaviours and childhood behaviour disorders. Psychologists use evidence-based approaches that are tailored to suit each client and circumstance and they assess, diagnose and treat a wide range of clients and areas of concern.