Doctors make a psychiatric diagnosis of a patient by performing a series of information-gathering activities, such as an interview to determine the patient's symptoms and giving the patient a physical examination. During a patient interview, a doctor will ask for a full medical history, including an explanation of how long the patient has been feeling or experiencing the symptoms that led him to seek a diagnosis. The medical exam is used to look for any possible physical indications or causes of the mental illness symptoms from which the patient is suffering, because a physical disease can have symptoms that mimic a mental illness. If there are no signs of disease that would cause the symptoms, then a doctor may consult The Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), to make a psychiatric diagnosis.
DSM-IV is a diagnosis manual published by the American Psychiatric Association. It contains information for psychiatric diagnosis of both children and adults and is divided into five categories, each of which is called an axis. Once all the axes are considered, the doctor will make a psychiatric diagnosis and determine the necessary medical treatment to alleviate the symptoms of the illness.
Clinical syndromes or disorders, from anxiety disorders to somatoform disorders, fall under Axis I. Disorders are the different categories or types of mental illnesses. Depression, schizophrenia, substance abuse, learning disorders and phobias are all found in Axis I.
Axis II includes developmental disorders and personality disorders. Developmental disorders are those that first appear in childhood, such as autism and mental retardation. Personality disorders are called clinical syndromes, meaning the symptoms of the disorder last for three weeks or longer and affect the way a person interacts with or understands the world. Borderline personality disorders, antisocial disorders and paranoid disorders are all personality disorders.
Information about how a medical condition or disease can cause mental illness, or make a mental illness worse, is found in Axis III. Brain injuries, human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) are examples of some of the medical conditions with symptoms involving mental illness. The severity of psychosocial stressors, or life events that negatively influence a person's mental health, can deeply affect someone with a mental illness and may make the illness worse. The information about these stressors and how they affect a person with mental illness is listed in Axis IV.
Axis V contains the final stage of testing required to make a psychiatric diagnosis. Two tests utilize a rating scale that goes from 1 to 100; one test rates an adult patient's highest level of functioning, while the other rates a child's global assessment scale. The tests are different because children under the age of 18 have different social lives, behavior patterns and thought patterns than adults. Both tests help a doctor determine a patient's ability to function — or perform basic, often necessary tasks in life — and compare his current behavior patterns to his past behavior patterns. The rating also allows the doctor to understand how each of the other four axes affects the patient and what kinds of changes the patient can expect in the near future.