Prevalence of depression and other common psychiatric disorders in autoimmune diseases has been extensively documented. The association between subclinical autoimmunity and behavioural or psychiatric syndromes remains less studied. The best known example is raised titres of autoantibodies with high affinity for the basal ganglia in some obsessive compulsive spectrum syndromes (e.g. Paediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections). The possible role of autoimmunity in impulse control disorders remains understudied.

We proposed to study the relation between autoimmunity, affective bipolarity and impulsive psicopathology.

14 bipolar, 10 cluster B personality disorder inpatients. Titres for rheumatoid factor (RA), antithyroglobulin (ATG), antiperoxidase (APO) antinuclear (ANA), anti-neutrophil cytoplasmic (ANCA) and antistreptolysin (ASO) antibodies were measured in all subjects. Psychiatric assessment: non-structured psychiatric interview, MINI International Neuropsychiatric Interview and Millon Clinical Multiaxial Inventory-II.

21,4% of bipolar patients had positive ATG titre vs 11,1% in the cluster B personality group. 28,6% of bipolar patients had positive APO titre vs 22,2% in the cluster B personality group. 16,7% of bipolar patients had positive ASO titre vs 30,0% in the cluster B personality group. None of this differences reached significance.

ASO titre correlated significantly with antisocial (rho=0,435, p=0,043) and autodestructive (rho=0,461, p=0,031) ratings and almost significantly with borderline (rho=0,420, p=0,052) ratings.

The results obtained partly agree with the existing studies. As far as we know a possible correlation between ASOs and impulsive behaviour has not been previously described. The results obtained call for further investigation in the subject.