Part 37 discusses what one of the hindrances that can prevent you from placing a curse upon your adversaries. The obstacle mentioned above is alcohol and/or drug use. You can only place a curse upon someone if you are sober. Any curse spoken under the influence does not work. The effects must wear off before speaking a curse into existence.
The reference used is in Genesis Chapter 9 in which Noah could not curse Canaan immediately because Noah was drunk. After Noah sobers up the next day, the curse is evoked upon Canaan due to homosexual tendencies. Homosexuality always results with a curse for that person who chooses that particular lifestyle.