FAAH and major depressive disorder: Even though results of the limited clinical trials of FAAH inhibitors in MDD have been unfavorable or unknown, the preclinical data suggest that FAAH is a promising therapeutic target for pharmacological intervention in humans with MDD and provides opportunities for combining FAAH inhibitors with other treatment modalities, such as monoamine-elevating antidepressants, transcranial magnetic stimulation, or electroconvulsive shock therapy.