SERUM SEROTONIN LEVEL CAN BE USED AS A PREDICTIVE MARKER FOR DEPRESSION IN PATIENTS WITH TYPE 2 DIABETES MELLITUS. TRUE OR FALSE?

The possible connection between serum serotonin levels and depression in individuals with type 2 diabetes mellitus (T2DM) has gained considerable interest. By examining HAM-D scores, glycated haemoglobin (HbA1c) levels and serum serotonin in T2DM patients receiving antidiabetic medication, with or without antidepressant treatment, we aimed to assess how medication influences depressive symptoms, considering serum serotonin as a possible marker for depression. Our findings indicate that antidiabetic medication, particularly metformin, contributed to an improvement in depression symptoms, its effects-both antidiabetic and antidepressant-being enhanced when combined with an antidepressant. However, these improvements were not correlated with serum serotonin levels, which showed high variability even within the same group of patients. Consequently, our study does not support the use of serum serotonin as a predictive marker for depression in T2DM patients, as numerous other factors, including metabolic abnormalities, insulin resistance and inflammation, impact both conditions.