The relationship of serum progesterone and allopregnanolone levels with cognitive functions, anxiety, leep quality and serum BDNF level in euthymic male bipolar disorder patients

Bipolar disorder is a chronic psychiatric disorder with mood episodes and persistent symptoms in the interepisodic periods. It is known that residual symptoms such as cognitive impairment, subsyndromal anxiety symptoms, and sleep disorders continue in the euthymic period of bipolar disorder. There are few studies in the literature to understand the role of neurosteroids in the pathophysiology of bipolar disorder. In our study, we aimed to examine the relationship of bipolar disorder itself and its residual symptoms with serum allopregnanolone and progesterone levels, and the relationship between serum allopregnanolone levels and serum Brain Induced Neurotrophic Factor (BDNF) levels. Our study includes 41 euthymic male patients with bipolar disorder and age-, body mass index (BMI)- and smoking- matched 40 male healthy control subjects. Neuropsychiatric tests such as Stroop Test TBAG Form, Auditory Verbal Digit Span Test- Form B, Cancellation Test, Beck Anxiety Inventory, Pittsburgh Sleep Quality Index were applied to all individuals participating in the study and 5-7 ml of peripheral venous blood sample was taken from all participants. Serum allopregnanolone, progesterone and BDNF levels of all participants were measured. In our study, serum progesterone, allopregnanolone levels were found to be lower in bipolar patients and it was observed that the serum allopregnanolon level was decreased with prolonged disease duration. It was concluded that the neurocognitive test performances of all participants were better in correlation with the increase in allopregnanolone levels. Serum BDNF level were similar between groups and the there was no relationship between the duration of illness and serum progesterone, BDNF levels in bipolar patients. The results of our study support the hypothesis that allopregnanolone acts as an endogenous mood stabilizer in the etiology of bipolar disorder. In addition, allopregnanolone to be consider as an important research area in the cognitive impairment of mood disorders. Although we did not find a significant relationship between allopregnanolone level and sleep quality, anxiety symptoms, serum BDNF levels in our study, we thought that the relationship between allopregnanolone and these parameters can be a valuable area for future researchs. Keywords: Bipolar disorder, Allopregnanolone, Progesterone, BDNF, Cognitive, Sleep, Anxiety