We designed a prospective study to determine if an association exists between alexithymia, leptin levels and hopelessness in patients with major depressive disorder, before and after treatment.

The study included 170 patients suffering from major depressive disorder, and they were divided into 2 groups: 100 subjects with alexithymia (MDD-A) & 70 subjects without alexithymia (MDD-nonA). All patients received 12 weeks of fluoxetine treatment.

After 12 weeks treatment, the MDD-nonA group had a significant increase in leptin levels compared with the MDD-A group (25.7% vs 9.5%). In addition, there was a significant decrease in hopelessness level in the MDD-nonA group compared with the MDD-A group (35.0 % vs 17.6 %). At the index week and follow-up week, the MDD-A group showed significantly higher scores of alexithymia, Beck depressive index (BDI), and hopelessness than the MDD-nonA group; the MDD-A group had significantly lower levels of leptin than the MDD-nonA group. The correlation coefficients between alexithymia and BDI, between alexithymia and hopelessness, and between alexithymia and leptin levels were not statistically significant. However, the correlation coefficients among BDI, hopelessness, and leptin levels were significant.

Our findings supported the premise that alexithymia, decreased leptin levels, BDI, and hopelessness are related and that both decreased leptin levels and hopelessness are strongly associated with severity of depression . These findings further reveal that alexithymia and depression are distinct constructs.