BDNF and bipolar disorder: Li Li Z Z Zhang Zhang C C Fan Fan J J Brain-derived neurotrophic factor levels and bipolar disorder in patients in their first depressive episode: 3-Year prospective longitudinal study Brain-derived neurotrophic factor levels and bipolar disorder in patients in their first depressive episode: 3-Year prospective longitudinal study Br J Psychiatry Br J Psychiatry 2014 2014 10.1192/bjp.bp.113.134064 10.1192/bjp.bp.113.134064 supplied-pmid 25368363?