Chronic Use of Proton Pump Inhibitors: A Potential Link to Amino Acid Deficiency and the Development of Depression.

In recent years, the gut-brain axis (GBA) has been implicated in several vital physiological processes, including digestion, immunity, inflammation, and mood regulation. Disruption of this network is tied to the development of several pathological conditions, including mood disorders, inflammatory bowel diseases, and dementia. Proton pump inhibitors (PPI) are among the most utilized and easily accessible medications worldwide. Although they are effective at treating conditions, including gastroesophageal reflux disorder (GERD), peptic ulcer disease, Zollinger-Ellison syndrome, and erosive esophagitis, PPIs have several mechanisms that may precipitate protein and, thus, amino acid malnutrition. Our patient is a 34-year-old female with a longstanding history of GERD treated with proton-pump inhibitors who presented to the psychiatry clinic complaining of a six-month history of depression without extraneous psychosocial factors. Although the patient refused psychiatric intervention, she desired an answer for her symptoms, leading to the discovery of a severe tyrosine deficiency. As tyrosine is critical in the process of neurotransmitter synthesis, replenishment of the amino acid along with discontinuation of proton-pump inhibitors was found to relieve her depressive symptoms within a few short months. In this report, we seek to establish a link between the chronic use of proton-pump inhibitor medications and the development of mood disorders.