Hypothyroidism and hyperthyroidism in anxiety disorders revisited: new data and literature review.

Background: The need for thyroid screening of patients presenting with panic disorder (PD), social phobia (SP) or generalized anxiety disorder (GAD) remains uncertain.

Methods: We examined thyroid histories and serum testing in 169 patients, 92 with PD, 48 with SP, and 29 with GAD. Combined prevalence rates of hyperthyroidism and hypothyroidism were compared with expected rates (2.7%) derived from the population based Whickham Survey. Data from previously published studies were also compared with these expected rates.

Results: In our sample, only 2/169 patients had thyroid dysfunction detected by serum testing, but 5/169 [1/92 (1%) with PD, 1/48 (2%) with SP, and 3/29 (10%) with GAD], all currently euthyroid, reported a history of thyroid disease. The rates were statistically significant only for GAD (10.4%; z = 2.56, p = 0.01). However, combining prior PD studies that examined both thyroid history and test results with our data also suggests significantly elevated rates of thyroid dysfunction (6.5%; z = 4.69, p < 0.0001).

Limitations: As with previous data, the 95% confidence interval for our findings is broad, reflecting the instability of low rates of illness in relatively small samples. Further, methods for obtaining thyroid histories and tests were not uniform.

Conclusions: Despite relatively low yields on serum testing, lifetime prevalence of thyroid dysfunction does appear elevated for GAD and PD, with minimal data addressing this issue for SP. The data support the need to query GAD and PD patients regarding thyroid history and perform serum testing in those without prior testing.