Effect of escitalopram on thyroid function in patients with depression- a hospital based study

Introduction: Depression is a common, recurrent, clinically and biologically heterogeneous disorder. Depression is commonly associated with several endocrine disorders and patients should be routinely investigated for endocrine disorders. Mood and anxiety disorders are higher with thyroid dysfunction. This association is attributed to the hypothalamic-pituitary-thyroid (HPT) axis regulation. In hypothyroid patients the prevalence of depression was found 33.0% to 43.0% and for anxiety 20.0% to 33.0%. In case of hyperthyroidism it is even higher with 53.0% to 69.0% for anxiety and 30.0% to 70.0% for depression.  Materials and Methods: The study was conducted in the department of Psychiatry Sher-I- Kashmir Institute of Medical Sciences (SKIMS) Medical College and Hospital.The study sample comprised of 200 patients diagnosed with first episode depression (Major depressive disorder) attending psychiatric outpatient department by using DSM 5criterion. Patients with major depression entering a treatment with escitalopram were assessed with the Structured Clinical Interview for DSM-5 and were rated on the Hamilton depression rating scale (HAM-D). Blood samples were taken for TSH, thyroxine (T4) and triiodothyronine (T3) measurement. Patients were then assigned to receive escitalopram for 6 weeks, After 6 weeks the thyroid hormone assessment was repeated and HAM-D was again applied. Mean concentrations of TSH, were slightly raised which were statistically significant, T3 and T4 were within reference ranges. Patients who showed no or minimum clinical response were administered increased dose of escitalopram and patients in whom TSH showed a subclinical response were treated with venlafaxine and after 12 weeks, TSH decreased with improvement in HAM-D score.
Results: Majority of the participants were males, predominantly belonging to age group of 18-29 years, mostly having education up to middle school, working in semi-skilled or unskilled group and married. Clinical profile revealed that most of the patients had mild to moderate form of depression, a few also reported severe form of depression. Some of them had given family history of thyroid disorder and psychiatric illness. The Hamilton Depression Rating Scale-(HAM-D) analysis pointed towards presence of depression with mean score of 13.34 before start of treatment and 11.24 and 9.96 respectively after6 and 12 weeks of treatment. Most of the patients had no or negligible change in thyroid indices, some of them had changes within euthyroid range and some of them had changes within sub-clinical range, which were statistically significant.  Conclusion: Escitalopram was not associated with clinically significant changes in thyroid hormone levels in euthyroid patients suffering from depression. However, results suggest that patients with normal thyroid function, who were treated with escitalopram, are susceptible to minor insignificant changes which also demonstrate the safety of administering escitalopram in euthyroid patients with depression. Although, the patients on treatment with escitalopram do not need strict monitoring of thyroid hormone levels. However, regular and periodic assessments of thyroid function should be carried out in patients with depression.