Substance use was defined as use of illegal drugs (heroin, marijuana, cocaine, etc.), use of prescription drugs in ways other than prescribed or high risk alcohol use. (sciencedaily.com)
After the age of 35, the casual use of illegal drugs virtually ceases. (religion-online.org)
Use of illegal drug during breastfeeding is contraindicated as they may transfer over to your baby through your milk. (expressing-mama.com)