Background: Studies are inconsistent as to whether patients with bipolar disorder are more frequently affected by autoimmune thyroiditis.
Aim: To study the prevalence of autoimmune thyroiditis in offspring of bipolar patients.
Method: In 1998 140 children (age 12-21 years) of bipolar parents were evaluated psychiatrically using the K-SADS-PL and blood was drawn to determine thyroperoxidase antibodies (TPO-Abs) and serum TSH. Blood samples of high school students (aged 12-19 years, n=77) and young adults (aged 20-35 years, n=52) were used as comparisons. At follow-up the offspring were psychiatrically evaluated and tested for TPO-Abs and TSH twice (14 months and 55 months after enrollment).
Results: TPO-Abs were predominantly found in female bipolar offspring, who had a significantly higher prevalence of positive TPO-Ab titers (9 out of 57 female offspring subjects) as compared to the female high school and young adult comparisons (4 out of 103 female control subjects). In TPO-Ab positive offspring (n=11) a raised prevalence of 55% of thyroid failure (i.e. a raised serum TSH or l-thyroxine treatment) was evident. TPO-Ab positive offspring did not show a raised prevalence of mood disorders (or any psychopathology) as compared to the TPO-Ab negative offspring.
Conclusion: Our study suggests that bipolar offspring are more vulnerable to develop thyroid autoimmunity independently from the vulnerability to develop psychiatric disorders.