Furthermore, a study using cultured neurons indicated that short-term alcohol treatment (0.5-2 hours) activated the cAMP system and increased expression of BDNF and other factors, whereas more prolonged treatment (>24 hour) inhibited cAMP and decreased BDNF expression.14 BDNF and CREB are reported to play an essential role in the pathophysiology of depression15 which is the most common comorbidity of alcoholism. The gene discussed is BDNF; the disease is alcohol drinking.