BDNF and depressive symptom measurement: From the present study, it was evident that there was a statistically significant (p<0.001) negative correlation between BDNF levels and HDRS scores with a Pearson coefficient (r) value of (-0.562) and a statistically significant (p<0.001) positive correlation between IL-1 β levels and HDRS scores with a Pearson coefficient (r) value of (+0.743). In some previous studies, it was found that there is a positive correlation between IL-1β and the severity of depression, which is in accordance with the present study [30].