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Drug dependency: an overview of drugs

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Alcohol and Other Drugs

Drug dependency: an overview of drugs

Most cultures in the world use mind-altering substances of some kind, and adults who choose to use drugs do so for many reasons, and accept varying degrees of risk in doing so.

However, these risks increase after a traumatic brain injury or other type of brain disorder.


Three main categories of drugs

 Psychoactive drugs can be divided into three general categories according to how they affect the central nervous system:

• Stimulants
• Depressants
• Hallucinogens
Stimulants stimulate the central nervous system, increasing alertness and physical activity. Legal drugs include nicotine from cigarettes and caffeine in coffee or cola drinks. Illicit drugs in this area include amphetamines (or 'speed') and Ecstasy (usually called 'E').


Depressants depress the central nervous system. In a normal dose, they can lead to euphoria, relaxation, reduced coordination, disinhibition and lack of concentration. Larger doses may lead to nausea, unconsciousness and even death.

The most popular legal depressant is alcohol. Cannabis is the most popular illegal depressant. Benzodiazepines are prescription medications that are often used for their depressant effects. The opiate family of drugs includes heroin, morphine, codeine and pethidine. 


Inhalants are a range of chemical products that are inhaled to produce a high feeling. Many of these have a depressant effect and can be obtained from a variety of household products such as glue, aerosols and petrol.


Hallucinogens affect a person's perceptions, sensations, thinking and emotions. Examples include LSD, mescaline and psilocybin. Psilocybin is found in certain mushrooms that are known as "magic mushrooms" or "golden tops".


Commonly used drugs

Cannabis does not appear to cause long-term health problems is small occasional doses, although research strongly advises that it is avoided until the brain has fully developed. Those who should be particularly wary of cannabis include:

  • Children and teenagers
  • People with epilepsy who may suffer from fits
  • Women who are pregnant or want to get pregnant
  • People with schizophrenia or other mental health problems.


Research indicates the risks of long-term use include:

  • Higher risk of bronchitis, lung cancer and respiratory diseases
  • Loss of interest in activities, lacking energy and boredom
  • Loss of concentration, memory and learning abilities
  • Reduced sex drive and lowered sperm count/irregular menstrual cycles
  • Psychotic behaviour if there's a predisposition to mental illness. 


Chronic cannabis use can exacerbate many of the problems experienced by people with an acquired brain injury and delay or prevent relearning lost skills.
Cocaine  is a stimulant extracted from the leaves of the coco bush in South America. It is most commonly ingested nasally; however it can be injected too. Its effects can last anywhere from a few minutes to a couple of hours, depending on the method it's taken in. Prolonged use of cocaine can lead to insomnia, depression, anxiety, eating disorders, sexual dysfunction, hypertension, hallucinations, and cerebral atrophy. Nasal intake (snorting) can damage  the nasal septum.


Ecstasy, or methylenedioxymethamphetamine (MDMA), includes ingredients often difficult to obtain, so other substances may be substituted, creating a drug which is not quite MDMA and will have unpredictable affects. Common immediate effects of ecstasy include an increase of heart rate, blood pressure and body temperature, jaw clenching, teeth grinding, talkativeness, feelings of well-being and a closeness to others, loss of appetite, lowering of the seizure threshold and sometimes nausea. During the comedown, a person can feel physically exhausted (especially after dancing all night), depressed, irritable, and have difficulty sleeping and concentrating. Many drugs commonly used in the treatment of brain injury can cause serious illness or death when mixed with ecstasy. For example anti-depressant drugs, such as Prozac, Aropax, Zoloft, Nardil, Parnate and Marplan, can interact dangerously with ecstasy.


Inhalants  are a group of psychoactive substances composed of organic solvents and other volatile substances found in the typical household. Some of the most common are paint, petrol and glue. They are often inhaled from an open container or 'huffed' from a rag soaked in the substance and held to the face. The effects seen are often short-lived and include intoxication (resembling alcohol's effects), distortion of perceptions of time and space, headache, nausea, slurred speech and loss of motor co-ordination. Sniffing is most dangerous due to 'Sudden Sniffing Death Syndrome' (SSDS) which is the result often of heart failure. Long-term use can cause brain damage and damage to the central nervous system as well as hearing loss, bone marrow damage, liver and kidney damage and depletion of blood-oxygen levels. 

Heroin, a depressant, is particularly dangerous if there is an overdose, especially when injected. Many deaths have happened when heroin has been used with other central nervous system depressants, like alcohol or benzodiazepines. Injection can also cause a variety of problems with viruses such as hepatitis C and HIV/AIDS, vein infections and vein damage. Heroin can lead to high levels of dependency. 

Benzodiazepines are a very commonly prescribed sedative. There are many different brands, including Valium, Ducene, Alepam, Murelax, Serepax, Alodorm, Mogadon, Normison, Euhypnos and Temaze. Used medically, benzodiazepines can effectively reduce anxiety and sleeping problems for a short period of time until the body develops a tolerance to the drug. Many people do not realize these drugs are highly addictive, with withdrawals similar to that of heroin, but lasting much longer and potentially fatal if use is stopped immediately.

References and further information

Further information:



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