Biomarkers Based Diagnosis of Major Depressive Disorder

Abstract

Introduction newlineMental illness or state of MDD is generally diagnosed using comprehensive clinical evaluation. Currently, the diagnoses of the depressive disorders rely solely on the clinician s subjective identification of symptomatic clusters and scales which has the shortage of subjectivity and in routine practice, clinicians are typically challenged by fitting their patients presentations along a continuous scale of severity of depression into strict DSM-IV based diagnostic categories. Hence, over one-third of diagnosed depressed patients are not appropriately diagnosed and accuracy of symptom-based diagnosis stays extremely low ~47%, Neuropsychiatric conditions such as MDD do not arise due to single biological change, but rather result from interactions of multiple factors. Research over the past decade indicates that major depression is associated with dysregulated pathways related to inflammation, HPA axis, metabolic, neurotrophic etc. Therefore, choosing appropriate set of biomarkers instead of one biochemical parameter appears to be the key to diagnose state of cognitive decline due to MDD. newlineReview of Literature newlineThis chapter gives a historical background of the problem, describes important milestones and discusses the work done by other researchers in recent past. Past reports related to magnitude of MDD, causes of MDD, importance of biomarkers and different biomarkers that have the potential for diagnosis and assessment of MDD are discussed in this chapter. newlineThe biomarkers from these four categories have been evaluated in this study i.e. Myeloperoxidase (inflammatory), Epidermal Growth Factor (Metabolic), Brain Derived Neurotrophic Factor (Neurotrophic) and Prolactin (HPA axis). The subjects were patients being diagnosed as MDD on the basis of DSM IV criteria using Hamilton rating scale of depression. Towards these objectives, four different biomarkers pertaining to the distinct pathways have been taken into consideration. Noticeably, in this thesis four key biomarkers including BDNF, EGF, MPO and Prolactin