Depression is a common mental disorder that occurs all over the world with treatment resistance commonly seen in clinical practice. Ketamine exhibits an antidepressant that is more often used in the case of treatment-resistant depression (TRD) in MDD and BP. Research emphasizes that a healthy diet and the nutrients it contains can lower the risk of developing depression and form a strategy that supports conventional treatment. The aim of the study was to evaluate the patients' diet and to analyze the effect of ketamine on food intake among patients with TRD. The study involved 15 patients suffering from treatment-resistant depression and 15 healthy volunteers. The data required for the analysis were collected using the food frequency questionnaire (FFQ) and 4-day food diaries. The study group was statistically significantly less likely to consume milk and plain milk beverages, plain white cheese, wholemeal bread, various vegetables, wine, and drinks. Our results show several disorders in the eating habits of patients with treatment-resistant depression. After the administration of ketamine, the patients consumed significantly less protein, fats, monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA), fiber, tryptophan, vitamins, and minerals compared to the control group. There is a lack of research describing the effects of ketamine on nutrition. In order to confirm the results of the study, more participants are required, and the assessment of food diaries filled in at the patient's home with a longer interval after the last dose of ketamine as well.
Keywords: FFQ; diet; ketamine; nutrition; treatment–resistant depression.