Notes
1. Introduction to Abnormal Psychology
Abnormal psychology is the branch of psychology that deals with studying unusual patterns
of behavior, emotion, and thought, which may or may not be understood as precipitating a
mental disorder. It is an area that seeks to describe, explain, predict, and treat abnormal
behavior.
2. Defining Abnormality
2.1 Statistical Infrequency
Abnormality can be defined as statistically rare behaviors, which lie outside of the average
range of behavior. For example, having a very high IQ is statistically infrequent but not
typically labeled as abnormal.
2.2 Deviation from Social Norms
This definition considers behavior abnormal if it violates unwritten rules about what is
acceptable in a particular social group. However, norms vary across cultures, limiting this
approach.
2.3 Failure to Function Adequately
Proposed by Rosenhan and Seligman (1989), this approach states a person may be
considered abnormal if they are unable to cope with the demands of daily life.
2.4 Deviation from Ideal Mental Health
Marie Jahoda (1958) identified six criteria for ideal mental health, including positive self-
attitude, self-actualization, autonomy, and accurate perception of reality. Deviation from
these may indicate abnormality.
3. Classification and Diagnosis of Mental Disorders
3.1 DSM-5 and ICD-11
The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and the International
Classification of Diseases (ICD-11) are the two primary systems for diagnosing mental
disorders.