Psychopathology

Psychopathology is the study of mental illnesses, mental distress and abnormal or maladaptive behavior. Abnormal Psychology is a similar term used more frequently in the non-medical field of psychology. 

To understand what "abnormal" means, first consider "normal". Normal simply means average. People who behave normally are those who act and behave in an average, typical way. Statistically speaking, normal behavior is that which we would expect from the majority of people. Abnormal, therefore, refers to any behavior that is not typical. In the practice of psychology it has further come to mean mental illness. Simply, abnormal behavior is any behavior that deviates from the norm.

Causes of abnormal behavior are as follow:
1) BIOLOGICAL: genetic inheritance, medical conditions, brain damage, exposure to environmental stimulus
2) PSYCHOLOGICAL: traumatic life experiences, learned associations, distorted perceptions, faulty ways of thinking
3) SOCIOCULTURAL: disturbances in intimate relationships, problems in extended relationships, political or social unrest

Personality Disorder is basically a set of traits that combine to negatively affect your life. They have a wide range of causes and some are easier to treat than others.

List of Personality Disorders

•  The first group is the Eccentric Personality Disorder. These people often appear strange or peculiar to others.

 Paranoid Personality Disorder – individual generally tends to interpret the actions of others as threatening.
 Schizoid Personality Disorder – individual generally detached from social relationships, and shows a narrow range of emotional expression in various social settings.
 Schizotypal Personality Disorder – individual is uncomfortable in close relationships, has thought or perceptual distortions, and peculiarities of behavior.

•   The second group is the Dramatic Personality Disorder. These people have intense emotional mood swings and distorted perceptions of themselves and impulsive behaviors.

 Antisocial Personality Disorder – individual shows a pervasive disregard for, and violation of, the rights of others.
 Borderline Personality Disorder – individual shows a generalized pattern of instability in interpersonal relationships, self-image, and observable emotions, and significant impulsiveness.
 Histrionic Personality Disorder - individual often displays excessive emotionality and attention seeking in various contexts. They tend to overreact to other people, and are often perceived as shallow and self-centered.
 Narcissistic Personality Disorder – individual has a grandiose view of themselves, a need for admiration, and a lack of empathy that begins by early adulthood and is present in various situations. These individuals are very demanding in their relationships.

• The third group is the Anxious Personality Disorder. These people are often fearful and anxious of one or many things.

 Avoidant Personality Disorder – individual is socially inhibited, feels inadequate, and is oversensitive to criticism
 Dependent Personality Disorder – individual shows an extreme need to be taken care of that leads to fears of separation, and passive and clinging behavior.
 Obsessive-Compulsive Personality Disorder – individual is preoccupied with orderliness, perfectionism, and control at the expense of flexibility, openness, and efficiency.

References:
http://www.humana-military.com/library/pdf/depression-glossary.pdf
http://www.apa.org/divisions/div12/rev_est/anxiety.html