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Prescription drug misuse FAQs


WebMD Medical Reference
Medically Reviewed by Dr Rob Hicks

What is a drug addiction?

Drug addiction, or drug dependence, as it is sometimes known, is the compulsive use of a substance which results in physical, psychological harm. It is a chronic, often relapsing, condition which can lead to changes in the structure and function of the brain or body.

For most people, the initial decision to misuse prescription drugs is voluntary. However, over a period of time, changes in the brain caused by repeated drug misuse affect a person's self control and ability to make sound decisions.

Which prescription drugs are commonly misused?

Certain prescription medications, such as analgesics, sleeping pills, amphetamines and tranquillisers are commonly known for causing drug dependence. Three classes of prescription drugs that are often misused include:

  • Opioids used to treat pain
  • Central nervous system (CNS) depressants used to treat anxiety and sleep disorders
  • Stimulants used to treat narcolepsy (a sleep disorder)

How do opioids work on the brain and the body?

Since the early 1990s, doctors' prescriptions for opioid medications, such as codeine and morphine, have increased. That increase can be attributed to an ageing population and a greater prevalence and understanding of conditions with chronic pain. When taken as prescribed, opioids and other painkillers manage pain effectively, improving the quality of life for people with chronic pain.

Using opioids for a short-term period under medical supervision rarely leads to addiction or dependence. However, when used long-term, opioids may lead to pain medication misuse with a physical dependence.

When taken with substances that depress the central nervous system, including alcohol, barbiturates or benzodiazepines, opiods can be potentially fatal, increasing the risk of respiratory depression.

The euphoric feeling associated with opioids is usually mild. However this euphoric feeling can lead to psychological dependence, where there is a state of emotional craving. Physical dependence is a physiological adaptation to a drug characterised by extreme physical symptoms after stopping the medication, more commonly known as withdrawal symptoms. According to the British Medical Association "New Guide to Medicines and Drugs" opioid dependence is rare under professional medical supervision.

How do central nervous system (CNS) depressants work on the brain and body?

Benzodiazepines depress the CNS. They are taken by millions of people worldwide to treat anxiety and sleep disorders, including insomnia.They are generally prescribed to treat insomnia, tension, and anxiety.

CNS depressants affect the brain neurotransmitter GABA (gamma-aminobutyric acid). GABA works by decreasing brain activity, which results in a drowsy or calming effect.

Taking CNS depressants under medical supervision from a doctor is acceptable as they can monitor appropriate dosage levels. Initially, only a small dose is required to administer the desired calming effects, however, the longer the course of treatment the more likely it is the dose will be increased in order to sustain the same effect.

Using CNS depressants with alcohol is potentially fatal as they have the potential to slow down the heart and respiratory system. Suddenly stopping a course of CNS depressants, without medical supervision, can have life-threatening consequences such as causing seizures. Always consult your GP if you wish to stop taking them.

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