There are many Studies investigating the relationship between thyroid function and depression/psychological well-being few as a study conducted in 2006 which suggests that treating the thyroid abnormalities improves Quality of Life and psychological symptoms .Another study in 2006 concluded that in patient with SHT where the serum TSH level is in the 3.5-10.0 mIU/liter range, there were no neuropsychological dysfunction, and compared with healthy controls, there were no relief of symptoms related to hypothyroidism.
A study conducted in 2007 establishes a considerable relationship of subclinical hypothyroidism with psychiatric disorders and an increased incidence of sub syndromic depression and anxiety symptoms in subclinical hypothyroidism in association to the euthyroid group. A recent study of 2015 explains that the suboptimal thyroid function increases susceptibility to the occurrence of depressive symptom and represents a modifiable risk factor for depression.Treating the depressed period of bipolar affective disorder is a important clinical challenge. Use of antidepressant medications carries the risk of stir up mania and rising the incidence of mood cycling (19,20). Further, the few published reports of research in this area suggest that response to treatment may be not as good as for bipolar depression than for unipolar depression (21-23).Proposals to develop outcomes have incorporated multiple strategies, such as single drug and combination of drugs using both recognized and accepted mood stabilizers, in addition of a variety of antidepressants, and other augmentation approaches, includes rise in level of thyroid .
It has long been accepted that frank hypothyroidismcan lead to depressive symptoms (24), and it almost regularly does so in severe cases (25). In the early 1970s the development of assays for thyroid-stimulating hormone (TSH) provides the means to assess more subtle forms of hypothyroidism and thus to define subclinical hypothyroidism. In 1974,Wenzel et al. (26) introduced a system of grading hypothyroidism. In this classification, grade 1 defines overt hypothyroidism, and grades 2 and 3 define subclinical hypothyroidism. With the TSH assay and new definitions for subclinical hypothyroidism, it was then possible to gather Epidemiological data to document that the prevalence of subclinical hypothyroidism is greater than that of overt hypothyroidism (27,28).
Furthermore, patients with subclinical hypothyroidism were noted to have a higher than normal lifetime prevalence of depression (29-31). The converse, that depressed populations demonstrate a high prevalence of subclinical hypothyroidism, also has been demonstrated (32-34). For instance, the rates of subclinical hypothyroidism reported for depressed populations are higher (8%–17%) than the rate for the general population (5%). In refractory depression, the presence of thyroid abnormalities is even greater. Studies reviewed by Howland (35) consistently demonstrate a higher than normal risk of subclinical hypothyroidism, with prevalence rates of 30% and above in patients with refractory depression.Over the past decade, research findings have extended the relationship between thyroid function and mood disorders and have called into question the appropriateness of the accepted normal ranges for values on the standard thyroid function tests. For example, Prange et al.
(36) found that the pretreatment free thyroxine index (FTI) was lower in patients who had poorer responses to treatment than in antidepressant responders, even though all FTI values were within the normal range. Frye et al. (37) assessed thyroid function prospectively in 52 outpatients with bipolar disorder. The patients were given monthly assessments, including thyroid function tests, during 1 year of lithium treatment. Even though their FTI values were within the normal range, patients with lower mean FTI values had more affective episodes and more severe depressive symptoms.
In this study we examined the relationship between pretreatment thyroid values and antidepressant response in bipolar depression. We predicted that patients with lower values within the normal range would have poorer outcomes of initial antidepressant treatment.after going through thesis journal studies and literature it was found that there is a relationship between the thyroid abnormalities with bipolar depression and major depressive disorders
