IMPORTANCE OF STUDYING MDD

MDD or clinical depression is a common and serious mood disorder. It is a medical condition that includes abnormalities of mood, sleep, appetite, cognition, and psychomotor activity. It is among the most burdensome diseases worldwide, and as such has considerable adverse effects on the daily lives of individuals, increasing the cost of healthcare and reducing the efficiency of the workforce. In the age range of 15-44 years, it is a top cause of functional disability and the estimated economic burden of depression was $83.1 billion (including $26.1 billion medical costs, $5.54 billion suicide-related mortality costs, and $51.5 billion indirect workplace costs) in 2000 in the United States.4,5 The high medical costs arise due to treatment nonresponse and because initial treatment is not effective for recovery6; e.g, one study reported a response rate of 47% with initial

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treatment.

The reported treatment of MDD patients is through two methods: psychotherapy and pharmacotherapy. Psychotherapy includes cognitive behavioral therapy (CBT) and interpersonal therapy (IPT). CBT deals with the cognition of the patients as depression is considered to be maintained by distorted and biased cognition that affects the patient’s view. CBT links a collaborative working relationship between the clinicians and the patients. It has been shown that CBT is superior to placebo and no treatment conditions.8-11 However, the relative efficacy of CBT in comparison with psychotropic medications is questionable when dealing with severe depression patients.12 In addition, for patients with many complex mental issues such as personality and emotional issues, there is no scope within CBT for personal exploration and assessment of emotion. IPT differs from CBT in that IPT addresses interpersonal relationships to better the patient’s communications skills and self-concept.13 It has been shown that IPT is as effective as CBT in general.14,15 However, IPT may be less effective than CBT for MDD patients with personality disorders.16

The pharmacotherapy for treatment of MDD patients includes tricyclic antidepressants (TCAs), monoamine oxidase inhibitors (MAOIs), and SSRIs. TCAs are an older generation of antidepressants and are well studied and shown to be effective in up to 50-75% of patients.16 However, there are many issues with TCAs. For example, overdose of these drugs can cause death, and side effects (blurred vision, dry mouth, drowsiness, weight gain, difficulty urinating, sexual dysfunction, etc.) are difficult to handle, resulting in 30-40% of patients terminating their use of these drugs. The MAOIs have been shown to be as effective for MDD patients as the TCAs and also effective for some nonrespondent patients.17,18 Besides, these drugs also have many limitations, resulting in infrequent use. An issue with MAOIs is that there is potential interaction with other substances that can cause severe consequences, i.e., foods containing tyra- mine must be avoided during the use of these drugs. In addition, similar to TCAs, an overdose of these drugs can be severe. The side effects of MAOIs include weight gain, sedation, and orthostatic hypotension. Now the first line of MDD treatment is the new class of antidepressant called SSRIs. It has been shown that this new class of antidepressant is more effective than other antidepressants.19-21 The side effects of SSRIs as compared to TCAs and other antidepressants are minor and transient. The common side effects of SSRIs are headaches, decrease in appetite and sexual desires, and nausea. In addition, an overdose of SSRIs is safe but they are relatively expensive compared to TCAs. However, some studies reported similar compliance rates for SSRIs with other antidepressants.22

Despite all these available medications for MDD treatment, there is an issue for clinicians as well as for the patients. Since each pharmacotherapy class contains multiple antidepressants, e.g., the SSRIs include more than 20 antidepressants, the challenge is how to select a suitable antidepressant for a certain MDD patient. In the present clinical practice, many clinicians use a trial-and-error approach while recommending antidepressants to MDD patients; selection of antidepressants is also based on subjective assessment, which is a costly and inefficient way of treatment. Furthermore, the initial treatment or assessment of antidepressant efficacy needs 2-4 weeks. In case the antidepressant is not effective, the clinicians require changing the antidepressant and recommending a new one, which will also need around 2-4 weeks of time. This practice is time consuming, costly, and may increase the severity of depression in a particular patient due to prolonged treatment duration. This happens because of the absence of scientific evidence in the initial treatment and the patient’s diagnosis. To cope with such practices, the antidepressants require a scientific prediction for their efficacy about the patient’s treatment. Hence, quantitative assessment based on neuroimaging techniques such as EEG will support the clinicians in assessing the effectiveness of a particular antidepressant for a particular MDD patient.23,24

 
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