Mental Health Disorders - Merck Manuals Consumer Version

Health Topics & Chapters

Overview of Mental Health Care
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 and Stress-Related Disorders
Anxiety is a feeling of nervousness, worry, or unease that is a normal human experience. It is also present in a wide range of psychiatric disorders, 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.
Dissociative Disorders
Occasionally everyone has minor problems integrating 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 are absorbed—with personal concerns, a program on the radio, or a conversation with a passenger—or are just daydreaming. Such problems, referred to as normal dissociation, typically do not disrupt everyday activities.
Eating Disorders
Eating disorders involve a disturbance of eating or of behavior related to eating, typically including
Mood Disorders
Mood disorders are mental health disorders that involve emotional disturbances consisting of long periods of excessive sadness (depression), excessive joyousness or elation (mania), or both. Depression and mania represent the two extremes, or poles, of mood disorders.
Obsessive-Compulsive and Related Disorders
In body dysmorphic disorder, a preoccupation with one or more nonexistent or slight defects in appearance results in significant distress and/or impairs functioning.
Paraphilias and Paraphilic Disorders
Paraphilias are frequent, intense, sexually arousing fantasies or behaviors that involve inanimate objects, children or nonconsenting adults, or suffering or humiliation of oneself or the 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
Personality disorders are 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 Disorders
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.
Gender Dysphoria
Various terms are used to talk about sex and gender:
- Gender Identity
- Gender Dysphoria
Somatic Symptom and Related Disorders
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.
Substance-Related Disorders
Drugs are an integral part of everyday life for many people, whether the drugs are used for legitimate medical purposes or recreationally (see table Drugs with Medical and Recreational Uses).
Suicidal Behavior and Self-Injury
Suicide is death caused by an intentional act of self-harm that is designed to be lethal. Suicidal behavior includes completed suicide, attempted suicide, and suicidal ideation.
- Suicidal Behavior
- Nonsuicidal Self-Injury
  - Diagnosis
  - Treatment