En español
NIDA

Menu

Comorbidity: Addiction and Other Mental Illnesses

Glossary

Addiction: A chronic, relapsing disease characterized by compulsive drug seeking and use and by long-lasting changes in the brain.

Antisocial Personality Disorder: A disorder characterized by antisocial behaviors that involve pervasive disregard for and violation of the rights, feelings, and safety of others. These behaviors begin in early childhood (conduct disorder) or the early teenage years and continue into adulthood.

Anxiety Disorders: Varied disorders that involve excessive or inappropriate feelings of anxiety or worry. Examples are panic disorder, post-traumatic stress disorder, social phobia, and others.

Attention-Deficit Hyperactivity Disorder (ADHD): A disorder that typically presents in early childhood, characterized by inattention, hyperactivity, and impulsivity.

Bipolar Disorder: A mood disorder characterized by alternating episodes of depression and mania or hypomania.

Comorbidity: The occurrence of two disorders or illnesses in the same person, either at the same time (co-occurring comorbid conditions) or with a time difference between the initial occurrence of one and the initial occurrence of the other (sequentially comorbid conditions).

Conduct Disorder: A repetitive and persistent pattern of behavior in children or adolescents in which the basic rights of others or major age-appropriate societal norms or rules are violated.

Depression: A disorder marked by sadness, inactivity, difficulty with thinking and concentration, significant increase or decrease in appetite and time spent sleeping, feelings of dejection and hopelessness, and, sometimes, suicidal thoughts or an attempt to commit suicide.

Dopamine: A brain chemical, classified as a neurotransmitter, found in regions of the brain that regulate movement, emotion, motivation, and pleasure.

Dual Diagnosis/Mentally Ill Chemical Abuser (MICA): Other terms used to describe the comorbidity of a drug use disorder and another mental illness.

Major Depressive Disorder: A mood disorder having a clinical course of one or more serious depression episodes that last 2 or more weeks. Episodes are characterized by a loss of interest or pleasure in almost all activities; disturbances in appetite, sleep, or psychomotor functioning; a decrease in energy; difficulties in thinking or making decisions; loss of self-esteem or feelings of guilt; and suicidal thoughts or attempts.

Mania: A mood disorder characterized by abnormally and persistently elevated, expansive, or irritable mood; mental and physical hyperactivity; and/or disorganization of behavior.

Mental Disorder: A mental condition marked primarily by sufficient disorganization of personality, mind, and emotions to seriously impair the normal psychological or behavioral functioning of the individual. Addiction is a mental disorder.

Neurotransmitters: A chemical produced by neurons to carry messages from one nerve cell to another.

Post-Traumatic Stress Disorder (PTSD): A disorder that develops after exposure to a highly stressful event (e.g., wartime combat, physical violence, or natural disaster). Symptoms include sleeping difficulties, hypervigilance, avoiding reminders of the event, and re-experiencing the trauma through flashbacks or recurrent nightmares.

Psychosis: A mental disorder (e.g., schizophrenia) characterized by delusional or disordered thinking detached from reality; symptoms often include hallucinations.

Schizophrenia: A psychotic disorder characterized by symptoms that fall into two categories: (1) positive symptoms, such as distortions in thoughts (delusions), perception (hallucinations), and language and thinking and (2) negative symptoms, such as flattened emotional responses and decreased goal-directed behavior.

Self-Medication: The use of a substance to lessen the negative effects of stress, anxiety, or other mental disorders (or side effects of their pharmacotherapy). Self-medication may lead to addiction and other drug- or alcohol-related problems.

This page was last updated September 2010

Get this Publication

Cite this article

APA style citation

National Institute on Drug Abuse (2010). Glossary. In Comorbidity: Addiction and Other Mental Illnesses. Retrieved from http://www.drugabuse.gov/publications/research-reports/comorbidity-addiction-other-mental-illnesses/glossary

press ctrl+c to copy

​Research Reports

This series of reports simplifies the science of research findings for the educated lay public, legislators, educational groups, and practitioners. The series reports on research findings of national interest.