Opiates, sometimes referred to as narcotics, are a group of drugs which are used medically to relieve pain, but also have a high potential for abuse. Some opiates come from a resin taken from the seed pod of the Asian poppy plant. This group of drugs includes opium, morphine, heroin, and codeine. Other opiates are synthesized or manufactured. There are a number of synthetic opiates which are used as painkillers, such as methadone, which is often prescribed for heroin and opiate addiction. Collectively, opiates and synthetic opiates are called opioids.

Opiates resemble natural chemicals in the body that bind to sites called opiate receptors. There are 3 types of opiate receptors: Mu, delta and kappa, all of which have differing functions. Opiates act on numerous areas of the brain and nervous system, including:

  • The limbic system which controls emotions. Acting here, opiates can produce feelings of pleasure, relaxation and contentment.
  • The brainstem which controls things your body does automatically like breathing. Opiates act on the brainstem to slow breathing, stop coughing and lessen feeling of pain.
  • The spinal cord which transmits sensations from the body. Opiates also act here to decrease feelings of pain even following serious injuries. Whether it is medication like Vicodin or a street drug like heroin, the effects of opiates (and many other drugs) depend on how much you take and how you take it. If opiates are swallowed as pills they take longer to reach the brain. If they are injected they act faster and can produce a quick intense feeling of pleasure followed by a sense of well-being and a calm drowsiness.
When administered, opioids attach to the abovementioned receptors. They then activate the receptors since their chemical structure mimics that of the natural neurotransmitter. This similarity in structure tricks receptors and allows the drugs to lock onto and activate the nerve cells.

Opioids target the brain's reward system by flooding the circuit with dopamine. Dopamine is a neurotransmitter present in regions of the brain that regulate movement, emotion, cognition, motivation, and feelings of pleasure. The overstimulation of this system, which rewards our natural behaviors, produces the euphoric effects.

Opiate Addiction


Brains are wired to ensure that people will repeat life-sustaining activities by associating those activities with pleasure or reward. Whenever this reward circuit is activated, the brain notes the responsible activity, and teaches the individual to subconsciously continue the activity again and again. Because drugs of abuse stimulate the same circuit, individuals learn to abuse drugs in the same way.

Long-term opiate use changes the way nerve cells work in the brain. The nerve cells become accustomed to having opiates around that when they are taken away suddenly, the individual may experience a wide range of symptoms in the brain and body. These are known as withdrawal symptoms. The symptoms and severity of opiate withdrawals is dependent on age, usage amount and length of usage. Accordingly, individuals who have a longer history of opiate abuse will experience longer, more difficult withdrawal.