Interestingly, elevated BDNF levels have also been found in methamphetamine and ecstasy abusers, so it would seem that this BDNF/dopamine interaction may be complex and play a role in both antidepressant effects and the brain’s dopamine reward pathways, the latter of which may conceivably elevate or reduce substance abuse risks.23 Interestingly, the literature has shown that chronic antidepressant use also results in elevated serum BDNF, while a low serum BDNF has been associated with a variety of psychiatric conditions, including depression, anxiety, and SUD.23,24. Here, BDNF is linked to depressive symptom measurement.