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Cannabis facts

What is cannabis?

Effects of cannabis


Medicinal cannabis

Further information


Cannabis. Different forms of cannabis including dried leaves and resin block. © Australian Drug Foundation 2010.

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Please note: The information given on this page is not medical advice and should not be relied on in this way. Individuals wanting medical advice on this issue should consult a health professional.

What is cannabis?

Cannabis is a depressant drug, which means it slows down messages travelling between your brain and body. When large doses of cannabis are taken, it may also produce hallucinogenic effects. The main active chemical in cannabis is THC (delta-9 tetrahydrocannabinol).1

Other names

Marijuana, yarndi, pot, weed, hash, dope, gunja, joint, stick, Kronic (synthetic form), cone, choof, dabs, dabbing, BHO.

How is it used?

Cannabis is usually smoked or eaten and comes in 3 different forms:

  • Marijuana − the dried plant that is smoked in a joint or a bong. This is the most common form.
  • Hashish – the dried plant resin that is usually mixed with tobacco and smoked or added to foods and baked; such as cookies and brownies.
  • Hash oil – liquid that is usually added to the tip of a cigarette and smoked.1

It takes about an hour to feel the effects of eating cannabis, which means it's easy to have too much. If it's smoked the effects are usually felt straight away.2,3 However, smoking can cause a number of negative side effects, especially later in life.

Cannabis can also come in synthetic form, which may be more harmful than real cannabis.

Synthetic cannabis

Cannabis may also be refined into what are known as dabs or dabbing, slang names for concentrated butane hash oil (or BHO), a relatively new method of administering/ingesting cannabis that involves the inhalation of highly concentrated THC.

Butane hash oil and dabbing

Effects of cannabis

There is no safe level of drug use. Use of any drug always carries some risk. It's important to be careful when taking any type of drug.

Cannabis affects everyone differently, based on:

  • Size, weight and health
  • Whether the person is used to taking it 
  • Whether other drugs are taken around the same time 
  • The amount taken 
  • The strength of the drug

The effects of cannabis may be felt immediately if smoked or within an hour or two if eaten and effects may include:

  • Feeling relaxed and sleepy
  • Spontaneous laughter and excitement
  • Increased appetite
  • Dry mouth
  • Quiet and reflective mood1

If a large amount or a strong batch is taken, the following may also be experienced:

  • Trouble concentrating
  • Blurred vision
  • Clumsiness
  • Slower reflexes
  • Bloodshot eyes
  • Seeing and hearing things that aren't there
  • Increased heart rate
  • Low blood pressure
  • Mild anxiety and paranoia1,3

Long-term effects

Regular use of cannabis may eventually cause:

  • Memory loss
  • Learning difficulties
  • Mood swings
  • Regular colds or flu
  • Reduced sex drive
  • Difficulty having children (low fertility in males and females)
  • Needing to use more to get the same effect
  • Dependence on cannabis
  • Financial, work and social problems1,3

Smoking cannabis can also cause:

  • Sore throat
  • Asthma
  • Bronchitis
  • Cancer (if smoked with tobacco)1,3

Those with a family history of mental illness are more likely to also experience anxiety, depression and psychotic symptoms after using cannabis. Psychotic symptoms include delusions, hallucinations and seeing or hearing things that do not exist or are distorted.

Cannabis and mental health

Using cannabis with other drugs

The effects of taking cannabis with other drugs − including over-the-counter or prescribed medications − can be unpredictable and dangerous.

Cannabis + alcohol: nausea, vomiting, panic, anxiety and paranoia.4

Cannabis is sometimes used to help with the 'come down' effects of stimulant drugs, such as ice, speed and ecstasy. However, doing this can cause reduced motivation, poor memory,  mental health problems and dependency on both drugs.5


Giving up cannabis after using it for a long time is challenging, because the body has to get used to functioning without it. Withdrawal symptoms may last for only a week, but sleep may be affected for longer. Symptoms include:

  • Anxiety
  • Irritability
  • Aggressive and angry behaviour
  • Cravings for cannabis
  • Loss of appetite and upset stomach
  • Sweating, chills and tremors
  • Restless sleep and nightmares6

Information on withdrawal

Medicinal cannabis

Broadly speaking, medicinal cannabis is cannabis prescribed to relieve the symptoms of a medical condition, such as epilepsy. It is important to make the distinction between medicinal cannabis and recreational cannabis. Recreational cannabis is the form of cannabis that people use to get 'high'. Recently legislation has been passed in Australia to facilitate access to medicinal cannabis for certain medical conditions.

Medicinal cannabis

Further information



Reducing the risks




ADF SEARCH – Find further credible research and information on cannabis.

ADIN – Find other credible websites and apps on cannabis.


1. Brands, B. Sproule, B. & Marshman, J. (Eds.). (1998). Drugs & drug abuse (3rd ed.). Ontario: Addiction Research Foundation.

2. Julien, R., Advokat, C., & Comaty, J. (eds.). (2011). A primer of drug action (12th ed.). New York: Worth Publishing.

3. Campbell, A. (2000). The Australian illicit drug guide. Melbourne: Black Inc.

4. National Cannabis Prevention and Information Centre. (n.d.). Mixing weed with other drugs: What's the deal?

5. McAtamney, A. & Willis, K. (n.d.) Polydrug use among cannabis users.

6. National Cannabis Prevention and Information Centre. (2011). Cannabis Withdrawal.

7. Wagener, T. L., Siegel, M., & Borrelli, B. (2012). Electronic cigarettes: achieving a balanced perspective. Addiction, 107(9), 1545-1548.


Last updated: 5 May 2016

Information you heard is intended as a general guide only. This audio is copyrighted by the Australian Drug Foundation. Visit for more