The Schizoid Personality Disoder (more) appears more often in men than in women, but in general very seldom.
The person shows great social detachement and is restricted in emotional expressions. The person is indifferent to emotional expressions of others. They are not interested in social relationships, that's why they prefere to do things on their own. This can even be increased to the point that they are not interested in sexual relations. People with Schizoid Personality Disorder mostly do not suffer from their disorder, that is why they usually do not seek treament.
It is important to differentiate Schizoid Personality Disorder from Schizotypal Personality Disorder (More)
Diagnostic Criteria of DSM-IV
The DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, More) describes Schizoid Personality Disorder as a pervasive pattern of detachment from social relationships and a restricted range of expression of emotions in interpersonal settings, beginning by early adulthood and present in a variety of contexts, as indicated by four (or more) of the following:
This diagnosis is made when these sympoms do not occur exclusively during the course of Schizophrenia (More) (More), a Mood Disorder With Psychotic Features (More), another Psychotic Disorder, or a Pervasive Developmental Disorder (More) and is not due to the direct physiological effects of a general medical condition.