Heroin is an illegal drug, an opioid drug that's processed from morphine which occurs naturally in the seedpod of the Asian opium poppy plant. Out of all opiates, heroin is the most widely used and fastest acting opiate there is. Heroin is usually found in powder form and is either white or brown in color. Heroin usually appears as a white or brown powder or as a black sticky substance, known as “black tar heroin.” Heroin is extremely addictive and depending on the intensity of use, a person can become dependent very fast, and develop a Heroin addiction often requiring medical detoxification. In 2011, 4.2 million Americans aged 12 or older (or 1.6 percent) had used heroin at least once in their lives. It is estimated that about 23 percent of individuals who use heroin become dependent on it.
How Is Heroin Used?
Heroin can be injected, inhaled by snorting or sniffing, or smoked. All three routes of administration deliver the drug to the brain very rapidly, which contributes to its health risks and to its high risk for addiction, which is a chronic relapsing disease caused by changes in the brain and characterized by uncontrollable drug-seeking no matter the consequences.
How Does Heroin Affect the Brain?
When Heroin enters the brain, it is converted back into morphine, which binds to molecules on cells known as opioid receptors. These receptors are located in many areas of the brain (and in the body), especially those involved in the perception of pain and in reward. Opioid receptors are also located in the brain stem, which controls automatic processes critical for life, such as blood pressure, arousal, and respiration. Heroin overdoses frequently involve a suppression of breathing, which can be fatal.
After an intravenous injection of heroin, users report feeling a surge of euphoria (“rush”) accompanied by dry mouth, a warm flushing of the skin, heaviness of the extremities, and clouded mental functioning. Following this initial euphoria, the user goes “on the nod,” an alternately wakeful and drowsy state. Users who do not inject the drug may not experience the initial rush, but other effects are the same.
Regular heroin use changes the functioning of the brain. One result is tolerance, in which more of the drug is needed to achieve the same intensity of effect. Another result is dependence, character-ized by the need to continue use of the drug to avoid withdrawal symptoms.
National Institute on Drug Abuse, 2013