The text "Neurobiology of Addiction" explains that opiates, also called opioids, are natural or synthetic substances that have actions similar to those of morphine. Morphine is a naturally derived substance from the plant Papaver somniferum, or opium poppy. Opioid drugs are used clinically to treat pain, cough and diarrhea. They have the potential to become addictive, especially when not used exactly as directed by a doctor or pharmacist. If a person becomes addicted, he will experience withdrawal symptoms when trying to stop using the drug.
Why Withdrawal Symptoms Develop
The text "Essential Psychopharmacology" explains that drug dependence develops because the brain's cells are trying to adapt to a change in their environment; specifically the long-term presence of a drug. Opiates of abuse exert their effects by interaction with a specific cellular protein called the mu opioid receptor. When a person takes opioids for a long period of time, her body's cells adapt by making themselves less able to respond to the drug. It is a functional adaptation meant to allow the cells to continue to do their jobs normally despite the drug's presence; however, when the drug is suddenly discontinued, the cellular environment changes once again, disrupting cellular communication and causing withdrawal symptoms.
Sequence of Withdrawal Symptoms
The text "Clinical Manual of Addiction Psychopharmacology" explains that physical opioid withdrawal symptoms tend to follow a sequence characterized as early, middle and late symptoms. Emotional withdrawal symptoms are usually evident prior to the onset of the early physical symptoms, and include depression and fatigue.
Early Withdrawal
The "Clinical Manual of Addiction Psychopharmacology" explains that the early symptoms of opiate withdrawal include runny eyes and nose, excessive yawning and sweating. These physiological changes are attributable to an overactive sympathetic nervous system. This particular branch of what is known as the autonomic nervous system is responsible for the arousal known as the "fight or flight" response to a threat.
Middle Withdrawal
As the sympathetic nervous system continues to elevate its activity in the absence of opiates, withdrawal symptoms include difficulty sleeping, restlessness, dilated pupils, poor appetite, goosebumps on the skin, muscle tremors and emotional irritability. The discomfort caused by these symptoms is frequent cause for relapse in opiate addicted individuals, says "Essential Psychopharmacology."
Late Withdrawal
The late opiate withdrawal symptoms are characteristic of high rates of release of neurotransmitters such as adrenaline. The "Clinical Manual of Addiction Psychopharmacology" states that the early and middle symptoms may seem worse in the late phase, and additional symptoms may be present. These include racing heart, nausea, vomiting, diarrhea and stomach cramps, muscle spasms and weakness, high blood pressure and deep pain in the bones.
References
- "Neurobiology of Addiction;" George F Koob and Michel Le Moal; 2006
- "Essential Psychopharmacology: Neuroscientific Basis and Practical Applications (2nd Edition);" Stephen M. Stahl; 2002
- "Clinical Manual of Addiction Psychopharmacology;" Henry R. Kranzler, M.D. and Domenic A. Ciraulo, M.D.; 2005
