Mental health (psychiatric or psychologic) disorders involve disturbances in thinking, emotion, and/or behavior. Small disturbances in these aspects of life are common, but when such disturbances cause significant distress to the person and/or interfere with daily life, they are considered mental illness or a mental health disorder. The effects of mental illness may be long-lasting or temporary.
Anxiety is a feeling of nervousness, worry, or unease that is a normal human experience. It is also present in a wide range of mental health conditions, including generalized anxiety disorder, panic disorder, and phobias. Although each of these disorders is different, they all feature distress and dysfunction specifically related to anxiety and fear.
Many people occasionally experience minor problems with a gap in their memories, perceptions, identity, and consciousness. For example, people may drive somewhere and then realize that they do not remember the drive. They may not remember it because they were absorbed—with personal concerns, a program on the radio, or a conversation with a passenger—or just daydreaming. Such problems, referred to as normal dissociation, typically do not disrupt everyday activities.
Mood disorders are mental health conditions that involve long periods of excessive sadness (depression), excessive elation (mania), or both. Depression and mania represent the 2 emotional extremes of mood disorders.
Obsessive-compulsive disorder is characterized by obsessions, compulsions, or both. Obsessions are recurring, persistent, unwanted, anxiety-provoking, intrusive ideas, images, or urges. Compulsions (also called rituals) are certain actions or mental acts that people feel driven to repeatedly perform to try to lessen or prevent the anxiety caused by the obsessions.
Paraphilias are frequent, intense, sexually arousing fantasies or behaviors that involve inanimate objects, children or nonconsenting adults, or suffering or humiliation of the person or a partner. Paraphilic disorders are paraphilias that cause distress or cause problems functioning in the person with the paraphilia or that harm or may harm another person.
Personality disorders are mental health conditions that involve long-lasting, pervasive patterns of thinking, perceiving, reacting, and relating that cause the person significant distress and/or impair the person's ability to function.
Schizophrenia and related psychotic disorders— brief psychotic disorder, delusional disorder, schizoaffective disorder, schizophreniform disorder, and schizotypal personality disorder—are characterized by psychotic symptoms, and often by negative symptoms and cognitive dysfunction.
Sex refers to biological characteristics (such as genitals, chromosomes, and hormones) used to categorize a person as male or female sex. Gender identity is how people see themselves, whether masculine, feminine, or some other gender identity, which may or may not correspond sex at birth.
Somatic symptom and related disorders are mental health disorders characterized by an intense focus on physical (somatic) symptoms that causes significant distress and/or interferes with daily functioning.
Medications and other substances, whether used for legitimate medical purposes, as a habit (for example, caffeine), or recreationally, are an integral part of everyday life for many people (see table Drugs with Both Medical and Recreational Uses).