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.
Heroin/Methadone use has been seen to cause growth retardation unrelated to maternal diet or prenatal care in 50% of infants born to addicted mothers. In utero violent kicking can occur if the mother withdraws. Ten percent of infants have chromosome changes.