Marijuana use is commonly thought to enhance<unk> ual pleasure. There is limited scientific research on the effects of marijuana and<unk> , however, and it is not well understood. The lack of research is in part due to U.S. drug policies centered on prohibition. In addition, the effects are difficult to study because<unk> ual arousal and functioning are in themselves extremely complex and differ among individuals. Moreover, marijuana affects people differently. As a result, it is challenging to study. Men and women report greater<unk> ual pleasure after having consumed marijuana, but there is no direct scientific evidence of the effects on the physiological components of the<unk> ual response cycle when using the drug.
Cannabis and sex
Heroin
Khat
Synthetic cannabinoids
Sex and drugs
Phencyclidine
Alcohol 
Crack cocaine