Thyroid disorders causes depression

Hypothyroidism is a very common entity seen in our clinical practice, there are many symptoms encountered for which one may suspect of hypothyroidism like baradycardia or low pulse rate, goitre, cold intolerance weight gain, decreased libido etc. There may be changes in skin and hairs too.

Hypothyroidism and depression

One of the most common symptom of hypothyroidism is depressed mood. Hypothyroidism can often lead tofrank depression that usually respond to thyroxine treatment. However most patients with major depression are euthyroid. On further assessment, a number of subtle abnormalities in the hypothalmus-pitutary axis occurs in large proportion of depressed patients that include alteration in serum concentration of thyroid hormone and TSH.

According to the review made by studies done, the prevalence of depressive symptoms in hypothyroidism is approximately 50%, whereas in hyperthyroidism it reaches upto 28% of the cases. Clinical depression is reported to occur in less than 40% of cases of people suffering from hypothyroidism. There is a strong possibility that the presence of subtle thyroid dysfunction is a negative prognostic factor for depression and may demand specific therapeutic intervention.

Thyroid dysfunction and depression have overlapping features that can cause misdiagnosis. In addition to specific symptoms of hypothyriodism likeconstipation, appetite decrease, decreased concentration, decreased libido, delusions, depressed mood, diminished interest, increased sleep, weight gain and fatigue seem to appear more frequently in patients with comorbid depression and hypothyroidism. Hence the presence of these symptoms should be a warning sign to clinicians for the need of thyroid investigations.

Action of thyroid hormone on brain

Thyroid hormone has important actions in the adult brain, and is associated with neuropsychiatric complaints and symptoms. These symptoms constitutes a long spectrum of emotional and cognitive problems directly related to changes in the brain secondary to multiple factors, and the major factor include direct effects of thyroid abnormalities and hormone deprivation.

In severe hypothyroidism there may be melancholic depression and even dementia. On treatment there is an improvement and may even comes out to be in a normal stage when a patient becomes euthyroid.

Diagnostic criteria in hypothytoidism with depression

The thyroid cause of depression can be established by seeing the following diagnostic criteria.

A positive family history increases the risk of having a thyroid abnormalities in a patient with depression.

If the depression or anxiety is of acute onset or occurs suddenly, then a thyroid abnormality can be suspected.

It is a general feature that depression is commonly seen in hypothyroidism while a panic attack or anxiety neurosis is seen in case of hyperthyroidism.

When a depression doesnt respond to conventional antidepressant the cause of depression may be suspected due to hypothyroidism, the cerebrospinal fluid is thus examined which may show increased free T4 level. This decreases on treatment and thus a patient may show signs of improvement.

Thus depression may be treated by behavioural therapy, antidepressants, but when there is no improvement, dont forget to analyse thyroid status of the patient.