Background: Mental illness, including anxiety disorders, is linked to accelerated cell aging. This is evidenced by shorter leukocyte telomere length. Cells with critically short telomeres may undergo apoptosis. In dividing cells, telomere shortening is counteracted by the telomeraseenzyme. Telomerase is reportedly low following chronic psychological stress. We hypothesized that a psychological treatment may increase telomerase activity, less telomere attritionand greater symptom improvement.

Methods: Forty-six patients (91% SSRI naïve) with social anxiety disorder(SAD; mean age 31, 63% females) underwent a 9-week waiting period, and 9 weeks of Internet-delivered cognitive behavior therapy(CBT). During treatment, symptoms were assessed weekly using the Liebowitz Social Anxiety Scale (LSAS-SR). Fasting blood samples were collected twice before treatment, and at post-treatment. Genomic DNA was extracted using DNeasy® Blood & Tissue Kit (Qiagene) to assess leukocyte telomere length. Telomerase activity was detected by real-time telomeric repeat amplification protocol (RT-TRAP).

Results: Patients improved significantly on the LSAS-SR (p<.001; Cohen’s d=1.5). Pre-post changes in telomerase and telomere length correlated positively (Pearson’s r=.31, p=.05). Reduced telomerase activity (<33th percentile) was associated with less improvement and increased activity (>66th percentile) with more improvement on the LSAS-SR (Z=-2.4, p=.02).

Conclusions: We demonstrate, to our knowledge for the first time, that altered telomerase activity is associated with clinical response to a psychological treatment in a psychiatric population. The observed CBT effect on telomerase in patients with SAD is consistent with results from animal trials and a small previous study of antidepressants in humans. Thus, telomerase activation may play an important role in clinical recovery.