A variety of conditions are described as personality disorders. Unlike anxiety disorders, personality disorders have no apparent, distinct signs or symptoms. The individual continues to function, often effectively, in his or her environment. A person who has a personality disorder may respond inappropriately in certain situations or may interfere with others' interactions.

Antisocial Personality Disorder- One common personality disorder is termed the antisocial personality, characterized by a person's constant conflict with society. The antisocial individual may display behavior that is cruel, uncaring, irresponsible, and impulsive. Although he or she can distinguish right from wrong, the antisocial personality often does not care and therefore is usually in trouble with the law.

Passive-Aggressive Personality Disorder- People with passive-aggressive personality disorder are often uncooperative with others. They resent being told what to do, but they show their anger indirectly. For example, a passive-aggressive person who does not want to take part in a school activity may either forget to show up or may arrive late and leave early. He or she has not openly refused to participate, but the resentment is obvious by the failure to be reliable.

Schizophrenia- A mental disorder meaning split mind, schizophrenia disorder affects about 1 to 2 percent of the population and appears most frequently among people between the ages of 15 and 35. Schizophrenics are severely disturbed. They exhibit abnormal emotional responses or, in some cases, no emotional response at all. They may respond inappropriately in some situations. Some schizophrenics withdraw, often losing a sense of time and space. Others talk to themselves, act in an odd manner, or neglect to care for themselves. People with paranoid schizophrenic disorder mistrust others and are often suspicious. They may believe that they are being followed and that others mean to harm them.

Much research is being carried out to better understand schizophrenia. Some doctors believe its cause stem from a physical disorder. Others think it is genetic in nature. The disorder may come and go throughout life. Professional help is always recommended.