|Year : 2014 | Volume
| Issue : 1 | Page : 1-3
Screening for depression in thyroidology
Yatan Pal Singh Balhara1, Sanjay Kalra2, Ambika G Unnikrishnan3
1 Department of Psychiatry, National Drug Dependence Treatment Centre, All India Institute of Medical Sciences, New Delhi, India
2 Department of Endocrinology, Bharti Hospital and B. R. I. D. E., Karnal, Haryana, India
3 Endocrinologist and CEO, Chellaram Diabetes Institute, Bavdhan, Pune, India
|Date of Web Publication||2-Jan-2014|
Yatan Pal Singh Balhara
Department of Psychiatry, Room No. 4096, 4th Floor, Teaching Block, All India Institute of Medical Sciences, Ansari Nagar, New Delhi - 110 029
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Balhara YS, Kalra S, Unnikrishnan AG. Screening for depression in thyroidology. Thyroid Res Pract 2014;11:1-3
| Depression: The Public Health Burden|| |
Depression affects around 350 million people worldwide and continues to be one of the commonest disorders in society. Not only it is highly prevalent, it is associated with a significant burden as well. In fact, as per Global Burden of Disease, 2010 report depression is the leading cause of disability worldwide in terms of total years lost due to disability.  Depression reduces productivity, strains the health care systems and even contributes to mortality.
Few people with depression, however, find their way to a mental health professional. The treatment gap for depression worldwide has been estimated to be more than 50% by World Health Organisation, with values as high as 90% for some countries.  Even in developed societies over half of all patients with depression are not diagnosed, and the condition goes unrecognized. Stigma associated with the condition worsens the situation further.
Low and Middle Income countries (LAMI) such as India face a dual challenge of limited resources and high social stigma. While many regions of the country are without trained mental health professionals, stigma contributes to a delay in help seeking even in presence of treatment services. Most of the cases get untreated and an even greater proportion remains undetected. It is estimated that though 12.5% of all primary care patients are likely to have had a major depressive episode in the past 1 year, only half are fortunate to be diagnosed correctly. Of these, only half receive any form of treatment. Of those receiving some form of treatment, only 3 out of 8 persons get 'adequate' treatment, and of these, just two-thirds finally achieve remission. 
| Depression: The Burden in Thyroidology|| |
The relationship of thyroid dysfunction with psychiatric disorders, including depression, is well-established and documented.  Iodization of table salt as a simple and effective preventive public health intervention reflects the role of thyroid hormones in growth and development of human brain since the intrauterine period itself. 
The relationship between thyroid dysfunction and psychiatric disorder is bidirectional and spans the entire spectrum of thyroid dysfunction. This holds true in context of depressive disorders as well. Both hypothyroidism and hyperthyroidism are linked with an increased risk of depressive disorders. Also, patients with depressive disorders are also at a higher risk of overt and subclinical hypothyroidism. Moreover, this association is not an uncommon occurrence with studies reporting life time prevalence of depression among those with subclinical hypothyroidism to be twice as high as that in general population. In fact, subclinical hypothyroidism has been identified as a preventable risk factor for depression. 
It is hard to ignore depressive disorders in practice of thyroidology, especially when depression could be the first (and at times the only) clinical manifestation of underlying hypothyroidism.
However, the bigger debate is centered on how to approach this association in clinical settings? First, what should be the approach of a thyroidology clinic? Second, should standard practice include diagnosis and management of depression in persons presenting with thyroid disorders? Finally, who should carry out the identification and management of depressive disorders in these individuals?
| Screening for Depression|| |
To screen or not to screen?
Diagnosis and management of any medical condition requires resources in form of time, money and more importantly skill and favorable attitude. The same holds true for diagnosing and managing depressive disorder among individuals with hypothyroidism as well. Screening offers an effective and less resource intensive option to identify the individuals who require a detailed assessment for presence of depressive disorders.
Screening for depression has been identified as an essential part of good clinical practice in primary care. The United States Preventive Services Task Force (USPSTF) has recommended all adults for depression, but only in practices with systems which can ensure proper diagnosis, treatment, and follow-up.  This is so because screening helps only in identification of likely cases. The diagnosis remains to be confirmed using a detailed assessment before treatment can be initiated. There is of course a theoretical risk of a 'nocebo' effect, in which a hitherto healthy person develops depression because of a false positive screening test. The bulk of evidence, however, is in favor of screening for depression in primary care. 
Screening for depressive disorders is likely to be more relevant and productive in settings with an expectedly higher prevalence of the condition. Hence, an endocrine care setting, specifically a thyroidology clinic where depression is over represented, is an appropriate setting to screen for depressive disorders.
Hypothyroidism (both overt and subclinical), being a risk factor for depression, necessitates regular screening for depressive disorders in thyroidolgy clinics. The thyroidologist should remain alert for symptoms of depression in patients with hypothyroidism.
The challenge of screening
While it is important to screen for depressive disorders in thyroidology practice, it is equally challenging to put it into practice. When confronted with the need for universal screening of mental health status in their clinics thyroidologists tend to worry-a concern that is not entirely ill-founded.
Screening for depression in practice of thyroidology would mean investment of additional resources in terms of time, effort and even money. The time taken to administer detailed questionnaires, the need for dedicated, sensitized manpower, and the fear of losing focus upon the endocrinological aspects of disease, makes thyroid care professionals apprehensive of any such move. It is akin to adding confusion to an already complex clinical battlefield. The social stigma associated with talk of mental illness may also contribute to this reluctance. A simpler reason, though, can be the lack of familiarity with simple case-finding instruments, created to screen for depression and lack of clarity on what needs to be done after screening. In fact, answers to these basic questions could help ease the apprehensions due to other issues as well.
How to screen?
The screening instrument used to identify depression should be brief, simple and not too expensive. Also it should be valid, reliable, and acceptable. Measurement-based strategies for the diagnosis and management of depression are now accepted in primary care, as well as in psychiatry clinics. Similar to the quantitative tests used to quantify biochemical and hormonal abnormalities, screening for depression can be made using validated instruments such as the Patient Health Questionnaire-9,  Beck Depression Inventory (BDI),  and the Zung Self-Rating Depression Scale scale.  These instruments are brief (take around 5-10 minutes for administration), valid and effective for screening of depression. Some of these tools are available in Indian languages as well.
Research has shown that even a simple two question case-finding instrument can be used as a reliable and valid tool for screening depression. This tool based on two questions of PRIME-MD scale was proposed by Mary Whooley and colleagues over 15 years ago. Whooley et al.,  found it to have a sensitivity of 96% and specificity of 57%. These questions focus on depressed mood and anhedonia-two cardinal symptoms of depression. These two questions are-"During the past month, have you often been bothered by feeling down, depressed, or hopeless?" and "During the past month, have you often been bothered by little interest or pleasure in doing things?"
Patient Health Questionnaire-2 (PHQ-2), an abbreviated version of PHQ-9, has also been developed with two similar questions (assessing over the past 2 weeks). This instrument has been found to be 74% sensitive and 75% specific in adolescents. 
Screening instruments can be used to identify those likely of having depressive disorder. However, one must be clear of the difference between screening and diagnosis. Not all testing positive on these screening tools are likely to be diagnosed with depression. This is reflected in the less than perfect specificity of these screening instruments. Hence screening should be followed by a detailed evaluation to confirm (or refute) the diagnosis. Diagnosis of depressive disorder is carried out using structured diagnostic criteria given in International Statistical Classification of Diseases and Related Health Conditions-10 (ICD-10) of World Health Organization (WHO) or Diagnostic and Statistical Manual of Mental Disorders-IV-TR (DSM-IV-TR) of American Psychiatric Association. Overlap between clinical features of depression and hypothyroidism adds to the challenge of correct diagnosis. Moreover, possible interactions of medications used in management of depression make it imperative to entrust qualified mental health professionals (psychiatrists and psychologists) with this responsibility.
However, the role of treating endocrinologist does not end at identification of cases. They have an equally important and probably even more challenging task of explaining the findings of the screening test and rationale and need of visiting a qualified mental health professional. Allaying the apprehensions of the patients and answering their queries in this regard are of utmost importance to motivate them to reach the mental health professionals. Only then the efforts at screening will bear fruit.
The way forward lies in a collaborative care approach which brings together thyroidology and psychiatry. While this particular approach has not been highlighted in the context of hypothyroidism, it is gaining acceptance in other chronic diseases. Any apprehensions regarding the need to identify persons with subclinical hypothyroidism or overt hypothyroidism for depressive disorders should be put to rest. The availability of simple screening tools should encourage this practice. Managing depression adequately, will help in improving therapeutic outcomes by improving adherence to therapy. The first step, however, remains proper screening and identification.
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