Comprehensive Neuropsychiatric Pathophysiology encompasses the intersection of neurobiological mechanisms, psychopharmacological intervention, and evidence-based diagnostic reasoning. Mood stabilizers such as lithium modulate intracellular signaling cascades including inositol monophosphatase and glycogen synthase kinase-3 beta (GSK-3β), exerting neuroprotective effects through BDNF upregulation — therapeutic monitoring requires serum levels (0.6-1.2 mEq/L), renal function, and thyroid function due to lithium's effects on ADH and thyroid hormone synthesis. Anxiolytic pharmacotherapy includes SSRIs as first-line treatment (blocking serotonin reuptake transporter), SNRIs for comorbid pain conditions, buspirone as a 5-HT1A partial agonist for generalized anxiety, and benzodiazepines (GABA-A receptor positive allosteric modulators) reserved for short-term use due to tolerance, dependence, and withdrawal seizure risk. The clinician must apply DSM-5 diagnostic criteria systematically while ruling out medical conditions that mimic psychiatric presentations.