Abnormal psychology
The definition of what constitutes 'abnormal' has varied across time and across cultures, and varies among individuals within cultures. It is often associated with a mental disorder. Abnormal psychology can be described as an area of psychology that studies people who are consistently unable to adapt and function effectively in a variety of conditions. There are different ways to  classify mental disorders. Abnormal behaviors can be adaptive or maladaptive. Maladaptive abnormalities can cause suffering and social discomfort. These behaviors can also be irrational, unpredictable and dangerous.