As overweight and obesity are a growing problem in industrialized societies, they become a main focus
of many studies. The aim of this study was to determine whether there is an association between the
occurrence of polymorphisms in serotonin-related genes and the prevalence of depressive symptoms
in obese patients. Two polymorphisms were tested: a 44-bp insertion/deletion in the serotonin transporter
(SERT) gene and a single-nucleotide variation (1438G/A) in the serotonin 2A receptor (5-HT2A)
gene. The study involved 180 patients (41 men; 139 women) previously diagnosed as obese. All patients
were subjected to clinical, biochemical, and neuropsychological evaluation and genotyping. Amplification
of the gene fragments was obtained by the polymerase chain reaction (PCR) method. Products of
the genotyping were separated via electrophoresis. The intensity of depressive symptoms was measured
using the Beck Depression Inventory (BDI) and Hamilton Depression Scale (HAM-D). Clinically relevant
depressive symptoms were diagnosed in 39% of subjects. The lowest intensities of depressive symptoms
were ascertained in the group with the least advanced obesity, but this trend was statistically insignificant.
Small differences were observed in obesity indicators among three groups of patients with various
genotypes of the SERT gene, but these differences were also statistically insignificant. Furthermore, in
the context of the intensity of depressive symptoms, no significant associations were observed in these
two groups. Furthermore, no statistically significant differences were observed among specific obesity
parameters and intensity of depressive symptoms as a function of the 5-HT2A gene polymorphism. To
conclude, depressive symptoms were prevalent in obese participants: 39% of subjects experienced symptoms
of clinical relevance. However, no significant associations were observed between 5-HT2A and SERT
gene polymorphisms and depressive symptoms in this study group
