Split personality, also known as schizoid personality disorder, involves a number of chronic symptoms, including poor judgment, disorganized thinking, emotional instability, poor social relationships and an inability to control impulses. Characteristics of schizoid personality disorder include sensitivity, jealousy, irritability, mistrust of others, resentment, and delusions of grandeur. Evaluation of schizotypal personality disorder is performed by a specialized psychiatrist, and when the diagnosis of schizotypal personality disorder is clear, psychotherapy and biomedical treatments may be given.