Simply Psychology Logo

Abnormal Psychology

Abnormal psychology is a diVisuon of psychology that studies people who are "abnormal" or "atypical" compared to the members of a given society.

There is evidence that some psychological disorders are more common than was previously thought.

Depending on how data are gathered and how diagnoses are made, as many as 27% of some population groups may be suffering from depression at any one time (NIMH, 2001; data for older adults).

Definitions of Abnormality

Under this definition of abnormality, a person's trait, thinking or behavior is classified as abnormal if it is rare or statistically unusual. 

With this definition it is necessary to be clear about how rare a trait or behavior needs to be before we class it as abnormal

IQ graph

For instance one may say that an individual who has an IQ below or above the average level of IQ in society is abnormal. 

However this definition obviously has limitations, it fails to recognize the desirability of the particular behavior. 

Going back to the example, someone who has an IQ level above the normal average wouldn't necessarily be seen as abnormal, rather on the contrary they would be highly regarded for their intelligence.

This definition also implies that the presence of abnormal behavior in people should be rare or statistically unusual, which is not the case.

Instead, any specific abnormal behavior may be unusual, but it is not unusual for people to exhibit some form of prolonged abnormal behavior at some point in their lives.

Limitation: However, this definition fails to distinguish between desirable and undesirable behavior.

Statistically speaking, many very gifted individuals could be classified as ‘abnormal’ using this definition. The use of the term ‘abnormal’ in this context would not be appropriate.

Many rare behaviors or characteristics (e.g. left handedness) have no bearing on normality or abnormality.  Some characteristics are regarded as abnormal even though they are quite frequent.

Depression may affect 27% of elderly people (NIMH, 2001).  This would make it common but that does not mean it isn’t a problem

Under this definition, a person's thinking or behavior is classified as abnormal if it violates the (unwritten) rules about what is expected or acceptable behavior in a particular social group.

Their behavior may be incomprehensible to others or make others feel threatened or uncomfortable. Social behavior varies markedly when different cultures are compared.

For example, it is common in Southern Europe to stand much closer to strangers than in the UK.  Voice pitch and volume, touching, direction of gaze and acceptable subjects for discussion have all been found to vary between cultures.

With this definition, it is necessary to consider: (i) The degree to which a norm is violated, the importance of that norm and the value attached by the social group to different sorts of violation. (ii) E.g. is the violation rude, eccentric, abnormal or criminal?

Limitation: Social norms change over time.  behavior that was once seen as abnormal may, given time, become acceptable and vice versa.

For example drink driving was once considered acceptable but is now seen as socially unacceptable whereas homosexuality has gone the other way.

Until 1980 homosexuality was considered a psychological disorder by the World Health Organization (WHO) but today is considered acceptable.

Under this definition, a person is considered abnormal if they are unable to cope with the demands of everyday life.

They may be unable to perform the behaviors necessary for day-to-day living e.g. self-care, hold down a job, interact meaningfully with others, make themselves understood etc.

Rosenhan & Seligman (1989) suggest the following characteristics that define failure to function adequately:

o Suffering

o Maladaptiveness (danger to self)

o Vividness & unconventionality (stands out)

o Unpredictably & loss of control

o Irrationality/incomprehensibility

o Causes observer discomfort

o Violates moral/social standards

One limitation of this definition is that apparently abnormal behavior may actually be helpful, function and adaptive for the individual.

For example, a person who has the obsessive-compulsive disorder of hand-washing may find that the behavior makes him cheerful, happy and better able to cope with his day.

Many people engage in behavior that is maladaptive/harmful or threatening to self, but we don’t class them as abnormal

 Adrenaline sports

 Smoking, drinking alcohol

 Skipping classes

Under this definition, rather than defining what is abnormal, we define what is normal/ideal and anything that deviates from this is regarded as abnormal.

This requires us to decide on the characteristics we consider necessary to mental health.

Psychologists vary, but usual characteristics include:

o Positive view of the self

o Capability for growth and development

o Autonomy and independence

o Accurate perception of reality

o Positive friendships and relationships

o Environmental mastery – able to meet the varying demands of day-to-day situations

Limitation: It is practically impossible for any individual to achieve all of the ideal characteristics all of the time.

For example, a person might not be the ‘master of his environment’ but be happy with his situation.  The absence of this criterion of ideal mental health hardly indicates he is suffering from a mental disorder.

Ethnocentric: Most definitions of psychological abnormality are devised by white, middle class men. It has been suggested that this may lead to disproportionate numbers of people from certain groups being diagnosed as "abnormal." 

For example, in the UK, depression is more commonly identified in women, and black people are more likely than their white counterparts to be diagnosed with schizophrenia.

Similarly, working class people are more likely to be diagnosed with a mental illness than those from non manual backgrounds.

Perspectives of Abnormality

models of abnormality

Behaviorists believe that our actions are determined largely by the experiences we have in life, rather than by underlying pathology of unconscious forces.

Abnormality is therefore seen as the development of behavior patterns that are considered maladaptive (i.e. harmful) for the individual.

Behaviorism states that all behavior (including abnormal) is learned from the environment (nurture), and that all behavior that has been learnt can also be ‘unlearnt’ (which is how abnormal behavior is treated).

The emphasis of the behavioral approach is on the environment and how abnormal behavior is acquired, through classical conditioning, operant conditioning and social learning.

Classical conditioning has been said to account for the development of phobias.

The feared object (e.g. spider or rat) is associated with a fear or anxiety sometime in the past. The conditioned stimulus subsequently evokes a powerful fear response characterized by avoidance of the feared object and the emotion of fear whenever the object is encountered.

Learning environments can reinforce (re: operant conditioning) problematic behaviors. E.g. an individual may be rewarded for being having panic attacks by receiving attention from family and friends – this would lead to the behavior being reinforced and increasing in later life.

The cognitive approach assumes that a person’s thoughts are responsible for their behavior.

The model deals with how information is processed in the brain and the impact of this on behavior.

The basic assumptions are:

  • Maladaptive behavior is caused by faulty and irrational cognitions.

  • It is the way you think about a problem, rather than the problem itself that causes mental disorders.

  • Individuals can overcome mental disorders by learning to use more appropriate cognitions.

The individual is an active processor of information. How a person, perceives, anticipates and evaluates events rather than the events themselves, which will have an impact on behavior. This is generally believed to be an automatic process, in other words we do not really think about it.

In people with psychological problems these thought processes tend to be negative and the cognitions (i.e. attributions, cognitive errors) made will be inaccurate:

These cognitions cause distortions in the way we see things; Ellis suggested it is through irrational thinking, while Beck proposed the cognitive triad.

The medical model of psychopathology believes that disorders have an organic or physical cause. The focus of this approach is on genetics, neurotransmitters, neurophysiology, neuroanatomy, biochemistry etc.

For example, in terms of biochemistry – the dopamine hypothesis argues that elevated levels of dopamine are related to symptoms of schizophrenia.

The approach argues that mental disorders are related to the physical structure and functioning of the brain.

For example, differences in brain structure (abnormalities in the frontal and pre-frontal cortex, enlarged ventricles) have been identified in people with schizophrenia.

The main assumptions include Freud’s belief that abnormality came from the psychological causes rather than the physical causes, that unresolved conflicts between the id, ego and superego create anxiety.

cause of anxiety

Freud also believed that early childhood experiences and unconscious motivation were responsible for disorders.

unconscious motives for abnormal behavior

National Institute of Mental Health. (2001). Depression research at the National Institute of Mental Health. Retrieved from

Rosenhan, D. L., & Seligman, M. E. P. (1989). Abnormal Psychology Second Edition. New York: W.W. Norton.

How to cite this article:

McLeod, S. A. (2008). Retrieved

Privacy Policy | A-Z Index