The key points about schizoid personality disorder are:
1. It is characterized by a lack of interest in social relationships and a preference for solitary activities.
2. Diagnostic features include indifference to developing close relationships, deriving little satisfaction from family or social groups, and preferring solitary hobbies over interacting with others.
3. Potential causes include genetic and neurological factors. Treatment involves psychotherapy focused on social skills and relationships, as the condition is generally considered long-term.