As the global population ages, depression in older adults is emerging as a serious public health problem. It is currently estimated that nearly 8%-16% of older adults (aged >65 years) living in the community suffer from clinically significant depressive symptoms1, an indicator of significant morbidity and early mortality2. According to the World Health Organization (WHO), it is also the most important precursor to suicide and will be the second leading cause of global disease burden by 2020. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get Original Essay The overall prevalence of depression is 9%, major depressive episode is 36% and the average age of onset of depression is 31.9 years, in India.3. The advanced age of a depressed patient is a significant predictor of an unfavorable course with an increased risk of relapse3, a reduced probability of response to treatment4,5 and a reduced possibility of functional recovery6. Furthermore, the onset of treatment-resistant depression (TRD) is common among older adults, with an estimated rate of 26 to 41 per 100 person-years.7. Randomized controlled trials (RCTs) of antidepressants reveal a smaller treatment effect among older adults compared to younger age groups5. This difference may be related to differences in the pathophysiology and phenomenology of depression among older people. Inaccurate assessment and misdiagnosis of depression in its early stages can also prevent effective treatment of depressed individuals. Having been recognized as a multifactorial disease, the total contribution of genetic factors to the origin of the disease, heredity, is estimated at almost 40%8. Therefore, relevant DNA sequence variations in potential candidate genes contributing to susceptibility to depression remain to be explored. Numerous studies have reported the involvement of abnormal gene expression or single nucleotide polymorphisms (SNPs) of neurotransmitter genes in the development of depression.9. Neurotransmitters (NA) are chemical messengers that conduct signals from one nerve cell to another. They play a central role in the pathophysiology of brain disorders, therefore they are targets for pharmacological treatments. Many recent studies have shown that reduced levels of neurotransmitters at the synapse are the basis of depression or mood disorders10. Dysfunction of dopaminergic neurotransmission has also been suggested in the pathophysiology of depression. Several studies have consequently reported that plasma levels of the dopamine metabolite (HVA) were lower in depressed patients11. In contrast, suicide victims without a history of depression have normal levels of HVA, dopamine and NA, based on the results of some autopsy studies12. . Neurotransmitters play a fundamental role in these pathological states; therefore they are prime targets for treating nervous system disorders and mental health problems. Considering the urgent need to prevent mental disorders in the geriatric population and to clarify the genetic basis of mental illness and its complications; and with the growing understanding of the impact of genetic variability on the development of mental illness, a current case-control study was designed. It will provide us with a better understanding of the origin and pathogenesis of this complication. Please note: this is just an example. Get a custom paper now from our expert writers. Get a custom essay Furthermore, it will improve our knowledge of interindividual variation.