What are some ways drugs can affect your body?

Drug abuse can compromise the body's immune system, making you more susceptible to infection and illness.

They can cause damage to the nervous system, due to adulterants and toxins present in street drugs.

Chronic use (or even short-term use, for some drugs) can change the brain's sensitivity to its own neurochemicals, making it require the drug in order to function properly. This often creates dysphoria, reduced cognitive ability, psychosis, anxiety, and other psychological disorders.

Some drugs reduce appetite, resulting in an anorexic condition, which can wear away the body due to malnutrition. This usually leads to further organ damage.

Various other systems of the body can be compromised as well (such as the endocrine system through the use of hormones and/or steroids).