ABSTRACT
Chapter summary
Abnormality has sometimes been defined in terms of social deviancy (behaviour very discrepant from social norms). This definition is flawed because individuals not adhering to social norms can be happy (eccentrics) or outstandingly heroic (those who helped Jews in Nazi Germany).
Abnormality often involves the four Ds: deviance; distress; dysfunction; and danger (to the individual and to others). However, the boundaries of abnormality are unclear and it has a lack of defining features.
DSM-5 is one of the most popular systems for diagnosing mental disorders. Its reliance on assigning individuals to categories often minimises differences among those diagnosed with the same disorder but exaggerates differences among those diagnosed with different disorders. It also minimises culture-bound syndromes.
Dimensional systems (assuming symptoms lie along dimensions) are preferable to categorical systems such as DSM-5. They are more realistic because they are based on 368the assumption that the dividing line between normality and abnormality is fuzzy. They also make it easier to identify similarities among different mental disorders (e.g., the anxiety disorders).
Mental disorders are caused by several different factors in combination. According to the diathesis–stress model, there is a diathesis (vulnerability or predisposition) combined with stress (distressing environmental events).
The onset of major depressive disorder depends on negative cognitive schemas (e.g., unrealistic negative thoughts about oneself, the world, and the future) and genetic factors. Uncontrollable life events increase vulnerability to depression but the occurrence of controllable life events depends in part on genetic factors.
The onset of social anxiety disorder depends in part on genetic factors. These genetic risk factors are very similar to those associated with other anxiety disorders.
Social anxiety disorder also depends on life events shortly preceding its onset, and on parental rejection and overprotectiveness. However, information about parenting is often obtained years afterwards and may be biased and unreliable.
