A pervasive pattern of detachment from social relationships and a restricted range of affect in interpersonal settings, beginning by early adulthood and present in a variety of contexts. Sometimes thought to be on the high functioning end of the autistic spectrum. It is not regarded as a form of schizophrenia and is diagnostically differentiated from a schizotypal personality disoder.

A personality disorder characterized by pervasive detachment from social relationships and restricted range of emotions

A personality disorder marked by extreme shyness, flat affect, reclusiveness, discomfort with others, and an inability to form close relationships.

is characterized by lethargy, inattention, and occasional eccentricity. They exhibit slow and monotonal speech and are generally non-spontaneous. They are content to be alone and aloof. They prefer solitary pursuits, are reserved and reclusive, and rarely respond to others' feelings and actions. They are seen as "cold fish." Their thoughts and communications can be easily derailed by internal or external distractions.

persons with this disorder are often cold, distant, introverted, and have an intense fear of intimacy and closeness. Persons with schizoid personality disorder are often too absorbed in their own thinking and daydreaming that they exclude themselves from attachment with persons and reality.

Schizoid personality disorder (SPD) is a cluster A personality disorder characterized by a lack of interest in social relationships, a tendency towards a solitary lifestyle, and emotional coldness. SPD is reasonably rare compared with other personality disorders. Its prevalence is estimated at less than 1% of the general population.