BDNF and depressive disorder: Fifth, in our meta-analyses of changes in BDNF levels with treatment for acute mania or depression, we considered the studies as responders or non-responders using the mean values of the YMRS or HDRS scores of each study, and not of individual subjects, with the exception of the study of Rybakowski et al. [78], which provided data for responders and non-responders separately.