Bulgarian Journal of Psychiatry, 2024; 9(1):46-51

Serotonin deficiency and lactase intolerance – a clinical case

Tatyana Telbizova1, Elena Panayotova2

1Department of Psychiatry and Medical Psychology, Medical University – Varna

2Department of Propaedeu cs of Internal Medicine, Medical University – Varna

Abstract. Excessive dietary restrictions on tryptophan-rich foods or disturbances in its absorption can lead to serotonin deficiency associated with the pathogenesis of various mental disorders and certain gastrointestinal diseases. A clinical case of a 35-year-old woman, without a family history of mental disorders but with a child diagnosed with lactose malabsorption, is presented. Initial mental symptoms emerged 10 years ago with a par al anorexic syndrome, complicated by the development of obsessions, panic a acks, and depressive symptoms. Discontinuation of the 10-year treatment with sertraline led to complaints from the lower gastrointestinal tract and relapse of the psychopathological disturbances. Gene c analysis revealed the presence of the 13910 C/C genotype for hereditary primary lactase deficiency. In fructose and lactose malabsorption, unabsorbed carbohydrates form non-absorbable complexes with tryptophan, hindering its absorption. The application of complex therapeutic strategies involving a lactose-free diet, an depressant therapy with 50 mg/day sertraline, and supplementation with L-tryptophan at 220 mg/day restored the patient’s soma c and mental condition. This case serves as evidence of serotonin’s role in the gut-brain axis and highlights the need for an interdisciplinary approach in comorbid patients.

Keywords: tryptophan, serotonin deficiency, lactose intolerance, fructose malabsorption, psychopathological disturbances

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