According to Mental Health: A Report of the Surgeon General, mental disorders are defined as "diagnosable conditions that impair thinking, feeling and behavior, and interfere with a person's capacity to be productive and enjoy fulfilling relationships." The report uses the term mental illness to refer collectively to all diagnosable mental disorders. According to the landmark "Global Burden of Disease" study, commissioned by the World Health Organization and the World Bank, 4 of the 10 leading causes of disability for persons age 5 and older are mental disorders. Among developed nations, including the United States, major depression is the leading cause of disability. Also near the top of these rankings are manic-depressive illness, schizophrenia, and obsessive-compulsive disorder. About 15 percent of the U.S. adult population use some form of mental health service in any year.
Depression: Depressive disorders are serious illnesses that affect a person's mood, concentration, sleep, activity, appetite, social behavior, and feelings. Depressive disorders come in different forms, the most common being major depression (unipolar depression). Major depression, the leading cause of disability in the United States, affects over nine million adults in a given year. Despite the disabling effects of depression, it is highly treatable.
Bipolar Disorder: Bipolar disorder (manic depression) is a brain disorder involving episodes of mania and depression. It affects more than two million American adults. Effective treatments are available that greatly reduce the symptoms of bipolar disorder and allow people to lead normal and productive lives.
Schizophrenia: Schizophrenia is a severe and chronic brain disorder that affects approximately two million Americans today. Schizophrenia impairs a person's ability to think clearly, manage his or her emotions, make decisions, and relate to others. People with schizophrenia suffer terrifying symptoms that often leave them fearful and withdrawn. However, this illness is highly treatable, and new discoveries and treatments are continually improving the outlook for people with this disorder.
Anxiety Disorders: Anxiety disorders include panic disorder, post-traumatic stress disorder (PTSD), obsessive-compulsive disorder (OCD), generalized anxiety disorder, and phobias (social phobia, agoraphobia, and specific phobias). More than 19 million American adults suffer from an anxiety disorder in a given year, and many people have more than one anxiety disorder. Anxiety disorders frequently co-occur with depressive disorders, eating disorders, or substance abuse. Depending on the type of anxiety disorder(s) someone has, effective treatments can include medication(s), psychosocial therapies, or a combination of the two.