Relationship between serum cortisol level and telomere length in bipolar disorder

Objective: To investigate whether bipolar disorder and its clinical features are associated with telomere shortening and to reveal the effects of cortisol level on telomere length in bipolar disorder. Methods: The study included 38 patients diagnosed with bipolar I disorder and 32 age- and sex-matched controls. All patients were evaluated with HAMD, YMRS and CGI. TL length and serum cortisol levels were measured by taking blood samples from both groups. Real Time Quantitative PCR was performed to determine the leukocyte telomere length. Results: A significant difference was found between the telomere lengths of the patient and control groups (p<0.01). Although cortisol values were higher in the patient group, no significant difference was found (p>0.05). There was no significant difference between the groups according to the number of first attacks, psychotic features, seasonal features, presence of complete recovery and hospitalization (p<0.05). Conclusion: This is the first study to evaluate the relationship between cortisol level and TL in patients with bipolar disorder. In our study, we found that patients with bipolar disorder had significantly shorter telomere lengths compared to healthy controls. We concluded that the relationship between bipolar disorder and telomere length is independent of the clinical features of the disease. Our findings did not support the hypothesis that shortened telomere length is associated with serum cortisol level in bipolar patients. Key words: Bipolar disorder, telomere length, cortisol level