A mental disorder or mental illness is a psychological

Psychology

Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...

 or behavioral

Behavior

Behavior or behaviour refers to the actions and mannerisms made by organisms, systems, or artificial entities in conjunction with its environment, which includes the other systems or organisms around as well as the physical environment...

 pattern generally associated with subjective distress

Suffering

Suffering, or pain in a broad sense, is an individual's basic affective experience of unpleasantness and aversion associated with harm or threat of harm. Suffering may be qualified as physical or mental. It may come in all degrees of intensity, from mild to intolerable. Factors of duration and...

 or disability

Disability

A disability may be physical, cognitive, mental, sensory, emotional, developmental or some combination of these.Many people would rather be referred to as a person with a disability instead of handicapped...

 that occurs in an individual, and which is not a part of normal development

Developmental psychology

Developmental psychology, also known as human development, is the scientific study of systematic psychological changes, emotional changes, and perception changes that occur in human beings over the course of their life span. Originally concerned with infants and children, the field has expanded to...

 or culture

Culture

Culture is a term that has many different inter-related meanings. For example, in 1952, Alfred Kroeber and Clyde Kluckhohn compiled a list of 164 definitions of "culture" in Culture: A Critical Review of Concepts and Definitions...

. Such a disorder may consist of a combination of affective, behavioural, cognitive and perceptual components. The recognition and understanding of mental health

Mental health

Mental health describes either a level of cognitive or emotional well-being or an absence of a mental disorder. From perspectives of the discipline of positive psychology or holism mental health may include an individual's ability to enjoy life and procure a balance between life activities and...

 conditions have changed over time and across cultures, and there are still variations in the definition, assessment, and classification of mental disorders

Classification of mental disorders

The classification of mental disorders, also known as psychiatric nosology or taxonomy, is a key aspect of psychiatry and other mental health professions and an important issue for consumers and providers of mental health services...

, although standard guideline criteria are widely accepted.