There are many ways psychologists define “abnormal psychology.” But, at its root, the term refers to the study of behaviors and mental illnesses that are unusual and atypical — out of the societal norm. In addition, abnormal psychology deals primarily with major mental and behavioral disorders, or conditions and illnesses that detract from an individual’s mental, emotional, and behavioral health, negatively affecting or limiting their life experience. These disorders may also be defined by or include the way an individual’s mental or behavioral conditions might negatively affect those in their immediate social environment or society at large.

Abnormal psychology focuses on many different types of disorders as the field is broad in scope. Mood disorders such as major depression, bipolar disorder and dysthymia are among the most commonly diagnosed, along with anxiety disorders like generalized anxiety disorder, panic disorder, phobias and the less common obsessive compulsive disorder. Eating disorders such as bulimia nervosa and anorexia nervosa are also fairly common in certain populations.

Less common are the more atypical dissociative, psychotic and personality disorders such as schizophrenia, narcissistic disorder, and borderline personality disorder. Major developmental disorders like autism and dyslexia also fall under abnormal psychology.

Abnormal psychology is involved with all aspects of psychology, from research to practice. Psychological scientists use the scientific method of experimental research to learn about the causes and symptoms of various abnormal disorders as well as the effectiveness of potential treatments (cognitive, behavioral or medical). These scientists use the results of their experiments, the data and information gathered, to form theories, build on or revise existing ones, and develop strategies for the application of their research findings and theories.

Clearly, the study of abnormal psychology is an essential part of modern psychology. Whether it be experimental research, clinical behavioral and cognitive therapy, or medication-based treatment, most psychological work concerns abnormal psychology.