David Gersten, M.D. in Carlsbad holds California medical license G32898, board certification from the American Board of Psychiatry and Neurology, and a UCSD School of Medicine degree (1978), practicing integrative psychiatry from Pio Pico Drive. The practice pioneered amino acid therapy as a psychiatric treatment modality, utilizing comprehensive laboratory panels including neurotransmitter assays, cortisol testing, heavy-metal screening, and hair-mineral analysis to identify biochemical drivers of mood and anxiety disorders alongside diagnostic imaging coordination through SimonMed Imaging - Carlsbad. Polyvagal Theory and vagus-nerve interventions supplement the nutritional-psychiatry framework, addressing the autonomic nervous system's role in anxiety, depression, and chronic-illness presentations. Medication management balances targeted amino acid supplementation with conventional psychopharmacology when clinically indicated, with oral-health monitoring for psychotropic-medication side effects coordinated through providers such as Packard Dental on the Carlsbad corridor. The integrative model deploys individualized amino acid protocols calibrated to lab-derived neurotransmitter profiles, titrating serotonin, dopamine, GABA, and norepinephrine precursors to restore neurochemical equilibrium across treatment-resistant depressive and anxious presentations.