THC - Cannabis

UK Class B Illegal Drug

Cannabis stands as the most commonly used illicit substance in the United Kingdom, whether for recreational or medical purposes. Legally, this drug can only be prescribed by the NHS or a registered private physician, and then, strictly for severe conditions where clear clinical benefits have been established. Cannabis THC is also the most common drug that is drug tested for.

Medical research and global attitudes regarding Cannabis use, suggest a potential future for its decriminalisation, with the UK's Green Party presently incorporating this stance within their political agenda. However, should decriminalisation occur, Cannabis would still be subject to widespread drug testing, akin to alcohol, owing to its potential impairments on activities such as driving, operating machinery, and workplace performance and productivity.

As such attempting to drive a vehicle after smoking Cannabis (medical or recreational) would still be illegal under UK drug and driving law.


How long does it take to feel the effects of cannabis?

Absorption of THC, the main active ingredient in Cannabis, will vary between individuals as with any consumed drug, but here is a general guide.

  • When Smoked (1 - 2 Minutes)
  • When Eaten (45+ Minutes Average)


How long do the effects of Cannabis last?

Like most drugs Cannabis has a peak where its effects are most powerful. Again this will vary from individual to individual but here is a rough guide.

  • When Smoked (10-30 Minutes)
  • When Eaten (2 -4 Hours)


How long is Cannabis use detectable in the body?

The main active ingredient in Cannabis, that is tested for on a drug test is THC.

THC can be detected on a drug test for the following times:

Other common names for Cannabis


Frequently asked questions about Cannabis

Why do people smoke Cannabis?

Recreational Use

Many people enjoy the feeling of being stoned or high, different strains of cannabis can provide different highs.

Medical Use

Cannabis can be used to treat severe epilepsy, MS or nausea caused by chemotherapy

Is Cannabis dangerous?

All drugs carry risks, Cannabis is no exception. Cannabis is known to have many mental health side effects, including: mood swings, disturbed sleep and lack of motivation. Smoking cannabis can also create difficulties breathing and increases the risk of lung cancer.

The majority of users will not encounter serious mental health problems with light recreational use of Cannabis, however extreme heavy use cases can trigger induced psychosis with symptoms such as paranoid delusions.

Many users report the drug having unwanted effects such as increased anxiety and inducing panic attacks.

Cannabis remains an illegal drug in the UK with possession getting you up to 5 years in prison, an unlimited fine or both.

Is Cannabis addictive?

Cannabis is not thought to be chemically addictive, however heavy users can become dependant on the drug to perform everyday tasks such as sleeping, with many users suggesting they need the drug to feel "normal"

Identifying the signs of Cannabis use

Cannabis possesses a distinct aroma, earning it the colloquial name 'skunk.' Some liken its fragrance to that of popular lager beers like Stella Artois.

Cannabis users may also exhibit potential side effects, including mood fluctuations, bloodshot or glassy eyes, fatigue, and weight gain.

Cannabis Drug Information - dtk

Last Updated 23/10/2023

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