Major Depressive Disorder is a psychiatric condition marked by persistent feelings of sadness, despair, and a notable loss of interest. This can manifest in shifts in appetite, leading to changes in weight, disruptions in sleep patterns, persistent fatigue, diminished attention, and recurring thoughts of suicide. Various factors, including neurotrophic elements like BDNF, synaptic activity dysregulation, and imbalances in neurotransmitter function, particularly serotonin, are implicated in its development.