Abuse of anabolic steroids, however, can result in significant harm to the body. In humans, abuse can lead to coronary heart disease , sexual and reproductive disorders, immunodeficiencies , liver damage, stunted growth, aggressive behaviour , susceptibility to connective tissue injury, and (in females) irreversible masculinization. Similar side effects can occur in livestock and other animals. In horses , for example, anabolic steroids can cause liver damage and weakening of the tendons and can result in decreased testis size and sperm production in stallions and altered reproductive cycling in mares. Anabolic steroids are readily detected in urine and blood .
Most drugs of abuse are addictive. Addiction is a chronic, relapsing disease characterized by compulsive drug seeking and use despite negative consequences and by long-lasting changes in the brain. People who are addicted have strong cravings for the drug, making it difficult to stop using. Most drugs alter a person’s thinking and judgment, which can increase the risk of injury or death from drugged driving or infectious diseases (., HIV/AIDS, hepatitis) from unsafe sexual practices or needle sharing. Drug use during pregnancy can lead to neonatal abstinence syndrome, a condition in which a baby can suffer from dependence and withdrawal symptoms after birth. Pregnancy-related issues are listed in the chart below for drugs where there is enough scientific evidence to connect the drug use to negative effects. However, most drugs could potentially harm an unborn baby.