A commercial driver's license (CDL) is a driver's license required in the United States to operate any type of vehicle. 1  weighing 26,001 pounds or greater, or any combination of vehicles weighing 26,001 pounds or greater when towing a trailer weighing more than 10,000 pounds.
The cause of drug abuse is not fully known but likely include genetic predisposition, co-occurring conditions and environmental circumstances. Drug use and experimentation is common in pre-adolescents and adolescents, but only a small percentage of those users will go on to abuse drugs.hile many people use drugs, only a small percentage abuse drugs, but it has been noted drug abuse often runs in families, suggesting genetics is one of the causes of drug abuse.
Behavioral. 1  Children who experience abuse and neglect are at increased risk for smoking, alcoholism, and drug abuse as adults, as well as engaging in high-risk sexual behaviors.7,11. 2  Those with a history of child abuse and neglect are 1.5 times more likely to use illicit drugs, especially marijuana, in middle adulthood.12.