Introduction: Thyroid dysfunction may cause various psychiatric symptoms and disturbances. In addition, many factors affect the variable responses to hormone replacement. Many patients treated for Hashimoto thyroiditis(HT) report persistent impairments in general well-being despite long-term L-thyroxine (LT4) replacement and restoration of biochemical euthyroidism.
Aim: To investigate the prevalence of depression and anxiety in patients with HT on long-term LT4 replacement and potential associations with free T4 (FT4), TSH, and antithyroid peroxidase antibodies (anti-TPO) concentrations.
Subjects and methods: Cross-sectional, case-control study with 120 patients with HT on long-term LT4 replacement and 60 euthyroid control subjects, matched for age, gender, and educational level. Measurement of TSH, FT4 and anti-TPO was done. Evaluation of depression and anxiety using the Hospital Anxiety and Depression Scale (HADS) scores(self-reported symptom questionnaire). Patients and controls were further subdivided according to age: group A (2049 yrs) and B (5075 yrs). Fishers ANOVA analysis was used to compare means between (sub)groups. Spearmans correlation coefficient(r) was used to assess the correlations between hormone levels, anti-TPO, and HADS scores.
Results: Patients had higher TSH levels vs. controls in both age groups (A:3.27±1.94 vs. 1.98±1.01, P<0.001; B:3.38±1.86 vs. 0.69±0.90, P<0.001), and higher anti-TPO (A:2585.5±2813.9 vs 49.8±137.9, P< 0.001 and B:2582.3±2986.9 vs. 25.7±43.0, P< 0.001). Patients reported more depression and anxiety than controls: HADSD (A:6.91±4.32 vs. 3.42±3.02, P<0.001; and B:8.29±4.18 vs. 5.74±2.98, P=0.020) and HADSA (A:9.15±3.70 vs. 7.37±3.22, P>0.05, B: 10.56±4.16 vs. 7.89±3.21, P=0.009). HADSD correlated positively with both disease duration (r=0.418, P<0.001) and therapy duration (r=0.221, P=0.019); while HADSA correlated positively only with disease duration (r=0.292, P<0.001). HADSD and HADSA correlated positively with TSH (r=0.246, P=0.001 and r=0.202, P=0.005 respectively), with anti-TPO (r=0.170, P=0.021 and r=0.169, P=0.022 respectively); while only HADSD inversely correlated with FT4 (r=−0.156, P=0.030) and FT3 (r=−0.166, P=0.035).
Conclusion: Patients with HT have more anxiety and depression despite long-term levothyroxine replacement. These symptoms were associated with the duration of treatment and with higher anti-TPO concentrations.