Low CSF leptin in female suicide attempters with major depression

Background: Leptin is a hormone known to participate in the regulation of weight and appetite and is therefore of interest to examine in the context of major depressive disorder (MDD). Studies of circulating leptin have yielded variable results. We therefore decided to study leptin in cerebrospinal fluid (CSF). Methods: We measured leptin in cerebrospinal fluid (CSF) in 72 patients admitted after a suicide attempt. They were divided in two groups: patients with major depressive disorder (MDD) and patients with other diagnoses (non-MDD). They were also subgrouped according to the number of suicide attempts (one or repeated) and whether the suicide attempt method was classified as violent or nonviolent. Since CSF leptin was considerably lower in men than in women, statistical calculations were made for men and women separately. Results: We found that in spite of having similar body mass index (BMI) (P=0.1), women in the MDD group had lower CSF leptin than those in the non-MDD group (P<0.01). In contrast, no such difference was found among men. No significant differences were found between women with a first suicide attempt compared to those with a repeated one, or between women with a violent attempt compared to those with a nonviolent attempt. Limitations: The heterogeneity of the non-MDD group including patients with various diagnoses is the most important limitation of our study. Conclusions: CSF leptin is involved in the neuroendocrine dysfunction in women with suicide attempt and MDD. This finding contributes to the understanding of the metabolic symptoms in MDD.