| ICD9 = | }} Schizoid personality disorder (SPD) is a personality disorder characterized by a lack of interest in social relationships, a tendency towards a solitary lifestyle, secretiveness, and emotional coldness.Authur S. Reber- Dictionary of Psychology, Penguin p.690 (1995) SPD is reasonably rare compared with other personality disorders. Its prevalence is estimated at less than 1% of the general population.. As an interesting comment on the usual low-prevalence figures for this disorder, Philip Manfield in Split Self, Split Object, Arenson (1992) states that "I believe that the schizoid condition is far more common..... comprising perhaps as many as 40 percent of all personality disorders. This huge discrepancy is probably largely because someone with a schizoid disorder is less likely to seek treatment than someone with other axis-II disorders." p.204. Manfield backs this claim with a study by Valliant &