You can download PDFs of our Highs of Leeds posters from the links below.

Richer Every Month Poster

More energy poster

Choosing not to smoke poster

brain development poster

It comes from the cannabis plant. It varies in strength and forms:

Herbal cannabis is the dried leaves and flowering plants of the cannabis plant. It looks like tightly packed dried garden herbs. The main type of cannabis used is a herbal cannabis often called WEED or BUD

Cannabis resin is a brown/black substance that is scraped from the cannabis plant and pressed into lumps.

Cannabis is the most widely-used illegal drug in Britain, although the number of people using it in recent years has fallen.

The main active chemical in it is Tetrahydrocannabinol (or THC for short).

THC is the ingredient in cannabis that can make you feel very chilled out; happy and relaxed.

THC has also been linked to anxiety, paranoia and in some cases hallucinations.

You may feel relaxed and talkative. Colours and music may seem more intense.

You may feel sick, have panic attacks, become paranoid and depressed or hear voices.

You need to weigh up the short and long-term effects drugs can have on your mental health and your future.

Your brain is still developing until your mid 20s. Regular, heavy cannabis use makes it difficult to learn and use information. It has been linked to poor exam results. Cannabis users also find they lack motivation

Over 1900 young people in Leeds were surveyed through the My Health My School Survey from 2014 – 2017. The results showed that over 90% didn’t use cannabis.

Another survey of  young people in Leeds by the Social Marketing Gateway completed anonymously at home and returned in sealed envelopes showed similar results.


This figure came from research with a range of young people who use weed and who are engaging with Forward Leeds

Teenagers who regularly use cannabis are likely to find themselves increasingly isolated from their families and their friends who choose not to smoke weed.

Often they only hang out with others who choose to use cannabis and are less actively engaged with the world around them.

Studies have shown that even weekly use of cannabis as a teenager can cause declining brain function and potentially a lower IQ.

Even long periods of abstinence in later life cannot necessarily reverse these effects on the brain.

For more information see the World Health Organisation report The health and social effects of nonmedical cannabis use Section 6.1.2   Long-term cannabis use and cognitive function

Research suggests that cannabis is addictive and for teenagers the risk of developing an addiction is double that of those who begin using cannabis in later life. 25-50 percent of all regular (daily) users become addicted.

Over time, the persistent over stimulation of the body’s nervous system can cause changes in the brain that result in addiction; this is much more likely in people who start using cannabis when young and who are heavy users.

For more information read the World Health Organisation report The health and social effects of nonmedical cannabis use Section 9.1.4 What do we know about the long-term effects of regular cannabis use?

Over the past few years, research has strongly suggested that there is a clear link between early cannabis use and later mental health problems for those with a family history of poor mental health. There is a particular issue with the use of cannabis by adolescents.

Regular use of the drug appears to double the risk of developing a psychotic episode or long-term schizophrenia.

Read more on the Royal College of Psychologists website

Forward Leeds undertook a series of interviews with teenagers that have decided to stop using cannabis and this was their feedback.

The teenage brain seems to be more vulnerable to cannabis than the adult brain. Heavy or regular adolescent cannabis users show a range of issues including:

  • Problems with attention
  • Problems with learning
  • Problems with memory
  • An inability to switch ideas, change responses or be mentally flexible

For more information read the World Health Organisation report The health and social effects of nonmedical cannabis use section 4.1.4 Neurobiology of cannabis effects in adolescence.

Test results show that modern cannabis is much more potent than the weed of 30 years ago.

But the boost in power comes at a cost—modern cannabis mostly lacks the components touted as beneficial by medical cannabis advocates, and it is often contaminated with fungi, pesticides and heavy metals.

This is as a result of cannabis being grown strictly to increase the amount of THC it contains at the expense of CBD which supposedly has medicinal benefits.

In addition cannabis can often be treated with additional chemicals to increase its potency.

For more information read the article Potent Pot: Marijuana Is Stronger Now Than It Was 20 Years Ago on Live Science

Cannabis may be ‘cut’ with other substances to increase the weight and the dealer’s profits.

Impurities in cannabis may include a variety of substances. Labs have reports of glass and pesticides being found in herbal forms of cannabis; and with hash/resin frequently being mixed with a range of substances to increase weight and the dealer’s profits.

Combining weed and alcohol is likely to make you feel unwell.

A side effect of smoking weed, called “a whitey”, is more likely to occur if a person drinks alcohol before smoking.

Individuals may go pale and sweaty, feel dizzy with “the spins,” nauseous, and may even start vomiting. This is often followed by the need or strong desire to lie down.

When recreational drinking and smoking are combined, it is also easier to drink excessively and risk alcohol poisoning.

New information indicates that combining the two may cause individuals to over-use both substances and in some cases, can result in death.

For more information read Psychology Today on The Dangers of Combining Alcohol and Marijuana

Cannabis smoking may have a greater potential than tobacco smoking to cause lung cancer.

Although Cannabis produces less smoke than tobacco smoke it contains up to twice the concentration of the cancer causing carcinogens found in tobacco

Cannabis is less densely packed than tobacco cigarettes, and tends to be smoked without filters or smaller butts leading to higher concentrations of smoke inhaled.

Furthermore, smokers of cannabis inhale more deeply and hold their breath for longer meaning more poisonous carcinogens find their way into these lungs.

These factors are likely to be responsible for the five-fold greater absorption of carbon monoxide from a cannabis joint, compared with a tobacco cigarette of similar size despite similar carbon monoxide concentrations in the smoke inhaled.

For more information read Cannabis use and risk of lung cancer: a case-control study

A recent analysis using data from three large studies in Australia and New Zealand found that adolescents who used cannabis regularly were significantly less likely than those who didn’t use cannabis to finish high school or obtain a degree.

They also had a much higher chance of developing dependence, using other drugs, and attempting suicide.

Several studies have also linked heavy marijuana use to lower income, unemployment, criminal behaviour, and lower life satisfaction.

For more information read  Cannabis use and later life outcomes or Teenagers who use cannabis every day 60% less likely to finish school

In a recent study of 1,000 individuals participants who began weekly cannabis use before age 18 dropped IQ points.

Persistent cannabis users’ difficulties in thinking were evident to friends and family and measurable on psychological tests.

Moreover, among those who started using at this age quitting or cutting back did not fully eliminate the IQ loss.

For more information read the article Early-Onset, Regular Cannabis Use Is Linked to IQ Decline