Categories
Drug Abuse

Why is Heroin Addictive

The United Nations Office on Drugs and Crime confirms that over 500,000 people living in the United States are addicted to heroin.
Heroin is a highly addictive recreational drug that causes physical dependency to occur. The narcotic is produced from morphine. Morphine is a photo chemical or a chemical that is produced by a plant. It is extracted from the seed pod of the Asian poppy plant and has a similar molecular structure when compared to the endorphins synthesized by the human body.

What is Heroin?

Heroin is an opioid. Opioids are a class of drugs that include fentanyl, and pain relievers available legally by prescription, such as oxycodone (OxyContin®), hydrocodone (Vicodin®), codeine, and morphine. They mimic the structure of endorphins, a natural chemical synthesized by cells in the brain. Morphine has the same structure as endorphins.As heroin enter the body, it is converted back into morphine. The morphine molecules bind to the opioid receptors located on the cells in brain tissue. The binding of these molecules causes the neurons to release large amounts of dopamine, a neurotransmitter that causes intense feelings of euphoria, stress relief and pain relief that last several minutes.

The psychological need for the drug is so overwhelming that the user can not control its intake or consumption. Many heroin addicts were predisposed to addiction through first being prescribed opioids by doctors and physicians for pain management. By abusing prescription opioid medications such as OxyContin® and Vicodin®, a small percentage of these patients developed a long term addiction to opioids.

Heroin Changes the Brain

Researchers at the Beijing Institute of Basic Medical Science have proven that the structure of the brain is changed when it used over a long period of time. A dysfunction in specific neural pathways of the brain involved in risk and reward processing has notably been observed.The connectivity patterns of neurons at a resting state in the nucleus accumbens (NAc) which is a section of the mesocortical limbic circuit within the brains of heroin addicts are abnormal. There was greater connectivity between prefrontal cortex and the nucleus accumbens. There was less connectivity between areas of the brain involved with reward processing and the nucleus accumbens. Researchers have found that these patterns remained long after patients became abstinent from the drug. Some of these patients were abstinent for more than 15 years. They also found that 30% of these patients had a high relapse rate.

Heroin affects sections of the brain responsible for perceiving pain and euphoria. The National Institute on Drug Abuse confirms that receptors for morphine are present on cells in this portion of the brain. When the chemical binds to opioid receptors present on the outer membranes of the cells that regulate pain, as well as, breathing, heart rate and sleeping. Studies have also shown that long term heroin use is associated with reduced white matter in the brain. Scientists believe that this leads to impairments in decision-making, impulsivity and an inappropriate response to stress.

A Genetic Basis to Heroin Addiction

A genetic component is partially responsible for addictive behavior. Mary Jeanne Kreek of Rockefeller University states that multiple of genes are responsible for over 60% in the development of an addiction. These genes also have multiple alleles or forms. In a study conducted by O. Levran et al., 130 candidate genes were found to increase the susceptibility to heroin addiction. All the subjects who were genetically tested were of caucasian decent. Out of these 130 candidate genes, the most consistent signals came from the DNA encoding the opioid receptors (mu, kappa, delta), the 3B subtype of the serotonin receptors, the galanin neuropeptide and the casein kinase epsilon. Based on these findings, scientists believe that they have found the genetic roots of opioid addiction. They are confident that changes in the genes encoding the opioid receptors are the major targets for binding endorphins. They suspect that mutations in these receptors play a role in opioid relapse.