Chronic heroin abuse caused significant changes in the central nervous system of a drug addicted person. Common consequences include building first an addiction, and, then, a tolerance to certain effects of heroin. The brain of an adolescent abusing heroin changes considerably after a while and begin to resemble that of an Alzheimer's patient.
Addiction
Once the heroin reaches the brain, it is converted to morphine by the enzymes states the National Institute on Drug Abuse. Because the chemical structure of heroin resembles that of a natural neurotransmitter, heroine can binds to the opioid receptors, and activate the nerve cells just like neurotransmitters do. Opioid receptors are located in the "reward" and "pain" circuits and stimulation of these circuits causes intense feeling of pleasure and loss of pain. Heroin is highly addictive and can cause an addiction in a couple of weeks.
Tolerance
When heroin is used frequently, tolerance may develop says the National Institute on Drug Abuse. Thus, a drug-addict does not respond to heroin the way he initially did. It takes a higher dose of heroin to get the same effect. When opiate receptors have been repeatedly activated by morphine, the enzyme adapts and morphine no longer causes changes in cell firing.
Long-Term Effects
Dr. S. N. Ramage and colleagues conducted a postmortem study on 34 young people who had mostly been abusing heroin and methadone, and on 16 people who had never used drugs. Their findings, published in the "Neuropathology and Applied Neurobiology" Journal in May 20054 demonstrate that the brain of a young heroin abuser resembles that of an elderly Alzheimer's patient. The damage was most prominent in those areas of the brain related to learning and memory such as basal ganglia, and the hippocampus. Two proteins had built up the brains of the heroin abusers causing severe cell death in essential parts of the brain. The same proteins are also responsible for the cell deaths in the Alzheimer's patients. These findings are supported by those of Dr. James M. Prosser and colleagues showing that cognitive deficits are common among heroin addicts. The study was published in the "Substance Abuse Treatment, Prevention and Policy" Journal in March 2008.
References
- Interscience: Hyperphosphorylated Tau and Amyloid Precursor Protein Deposition is Increased in the Brains of Young Drug Abusers
- "Neurosciencel Letters": Dysfunctional Connectivity Patterns in Chronic Heroin Users
- National Institute on Drug Abuse: Heroin
- Substance Abuse Treatment, Prevention and Policy.:Character Pathology and Neuropsychological Test Performance in Remitted Opiate Dependence
