Prevalence of antiphospholipid antibodies in psychiatric patients users and non‐users of antipsychotics

Summary Past reports have suggested that antiphospholipid (a PL ) antibodies may emerge as a response to antipsychotics treatment, as a high prevalence of a PL antibodies in antipsychotics users has been observed. However, no control group of non‐medicated psychiatric patients was included in these reports. In a cross sectional study we determined the prevalence of a PL antibodies in 333 psychiatric inpatients. We compared the proportions of positive a PL antibodytests between users and non‐users of antipsychotics with adjustments for potential confounders. The proportion of antipsychotics users carrying at least one a PL antibody ranged from 10·8% to 27·0% compared with 6·8% to 27·2% in non‐users ( P  = 0·24, P  = 0·24) depending on the method of detection of lupus anticoagulant ( LA ). The prevalence of LA detected by dilute Russell viper venom time or partial thromboplastin time‐ LA was not different between antipsychotics users and non‐users (8·1% vs. 5·4%, P  = 0·53 and 18·4% vs. 18·2%, P  = 0·22), as well as the prevalence of Ig M and Ig G anti‐β2‐glycoprotein‐I antibodies, Ig M and Ig G anti‐cardiolipin antibodies(3·8% vs. 2·0%, P  = 0·75, 0·0% vs. 0·0%, P  = not applicable, 1·1 vs. 1·4%, P  = 0·91, 2·7% vs. 3·4%, P  = 0·71). In conclusion, a PL antibodies were frequently found in patients with psychiatric diseases and no significant increase in the prevalence of a PL antibodies was observed in antipsychotics users.