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Defining Mental Health and Abnormality

Defining Mental Health and Abnormality

What does it mean to be "mentally healthy" or "mentally ill"? Defining abnormality is one of the most challenging tasks in psychology. There is no single definition that psychologists universally agree on — each approach has strengths and limitations. Understanding these definitions is essential for GCSE Psychology.


Why is Defining Abnormality Difficult?

  • Behaviour that is considered "abnormal" in one culture may be perfectly normal in another
  • The line between "normal" and "abnormal" is not always clear — most psychological characteristics exist on a continuum
  • Definitions of abnormality have changed over time — homosexuality was classified as a mental disorder until 1973
  • Labelling someone as "abnormal" can be stigmatising and affect their self-esteem and treatment by others

Four Definitions of Abnormality

1. Statistical Infrequency

Statistical infrequency defines abnormality as behaviour or characteristics that are statistically rare — they deviate significantly from the average (mean) for the population.

In a normal distribution, most people cluster around the average, with fewer people at the extremes. Any characteristic that falls outside the normal range (typically the top or bottom 2.5%) is considered statistically abnormal.

Example: An IQ score below 70 (bottom 2.5% of the population) is considered statistically abnormal and may indicate an intellectual disability.

Strength Weakness
Objective — based on measurable data Does not distinguish between desirable and undesirable abnormality — an IQ of 150 is also statistically rare but is not a problem
Clear cut-off points — can identify when someone deviates from the norm Not all statistically rare behaviours are problematic — being left-handed is rare but not abnormal
Useful for diagnosis when combined with other criteria Does not account for cultural differences — what is rare in one culture may be common in another

2. Deviation from Social Norms

Deviation from social norms defines abnormality as behaviour that violates the unwritten rules and expectations of a society.

Social norms are the implicit rules about how people should behave in a given society. Behaviour that breaks these norms is seen as abnormal.

Example: Talking loudly to yourself in public may be seen as deviating from social norms in some cultures.

Strength Weakness
Takes social context into account Social norms vary between cultures — what is abnormal in one culture may be normal in another
Can identify behaviour that causes distress to others Social norms change over time — definitions of abnormality based on social norms are historically relative (e.g. homosexuality)
Useful in identifying behaviours that need intervention Can be used to control or punish people who are simply different, rather than genuinely disordered
Eccentric behaviour may be labelled as abnormal when it is harmless

3. Failure to Function Adequately

Failure to function adequately defines abnormality as the inability to cope with everyday life — when a person's behaviour or mental state prevents them from functioning in daily activities.

Signs of failure to function adequately include:

  • Inability to go to work or attend school
  • Inability to maintain relationships
  • Inability to look after oneself (hygiene, eating, shelter)
  • Causing distress to themselves or others
  • Behaving in ways that are irrational or dangerous
Strength Weakness
Focuses on the individual's experience — recognises personal suffering Some people with mental health problems may still function adequately (e.g. a person with depression who continues to work) — they would not be identified
Recognises that abnormality involves real difficulties in daily life Some people may choose not to conform to social expectations without being mentally ill (e.g. homeless people who choose to live that way)
Is person-centred — focuses on whether the individual needs help Who decides what "adequate functioning" means? This is subjective

4. Deviation from Ideal Mental Health

Deviation from ideal mental health defines abnormality as the absence of signs of good mental health. Marie Jahoda (1958) identified six criteria of ideal mental health:

Criterion Description
Self-actualisation Achieving your full potential
Autonomy Being independent and self-reliant
Accurate perception of reality Seeing the world as it really is
Environmental mastery Being able to meet the demands of any situation
Resistance to stress Having effective coping mechanisms
Positive self-attitudes Having good self-esteem and a positive self-image

The more of these criteria a person lacks, the more "abnormal" they are considered to be.

Strength Weakness
Positive approach — focuses on health rather than illness Sets an unrealistically high standard — very few people would meet all six criteria, so most people would be classified as abnormal
Provides a comprehensive picture of mental health The criteria are culturally biased — they reflect Western, individualist values (e.g. autonomy may not be valued in collectivist cultures)
Considers multiple aspects of mental health The criteria are difficult to measure objectively

Key Points

  • Four definitions of abnormality: statistical infrequency, deviation from social norms, failure to function adequately, deviation from ideal mental health.
  • No single definition is perfect — each has strengths and weaknesses.
  • Statistical infrequency is objective but does not distinguish desirable from undesirable rarity.
  • Social norms vary across cultures and time periods.
  • Failure to function adequately is person-centred but subjective.
  • Jahoda's ideal mental health criteria set an unrealistically high standard.