On the psychological level, the study cites a number of research reports indicating many heroin addicts also suffer from psychiatric disorders, including depression, antisocial personality disorder and post-traumatic stress disorder.

Once the heroin is smuggled into America, drug dealers cut, or dilute, the heroin (1 part heroin to 9 to 99 parts dilutor) with sugars, starch, or powdered milk before selling it to addicts. Also, quinine is added to imitate the bitter taste of heroin so the addict cannot tell how much heroin is actually present. Heroin is often sold in single-dose bags of 0.1 gram (0.03 oz.), each costing between $5 and $46 (1992). One pound of diluted heroin yields approximately 4,500 doses.

Rates of cocaine use by college students over the previous 5 years has varied between 2.0% of all students in 1994 to 4.8% in 2000.

In the US, opium was used to treat soldiers during the Civil War (1861-1865). During the late 1800s, doctors prescribed "tonics" containing opiates for many conditions. Rarely did these medicines list opiates as one of the ingredients. In fact, heroin was marketed as a cough medicine and a cure for morphine addiction. However, many physicians had concerns about possible addiction to these medicines.