Notes

Stimulants include caffeine - found in cola drinks and coffee, cannabis and amphetamines. They increase the transmission of signals from one nerve cell to the next. This increases alertness, heart rate and breathing rate. However, in the longer term, they can produce 'highs' and then extreme 'lows' or even depression. They can be addictive because the body needs a constant top-up to maintain the effect.
The alcohol in alcoholic drinks such as wines, beer and spirits is ethanol. It is a depressant. This means that it slows down signals in the nerves and brain.
Small amounts of alcohol help people to relax, but greater amounts lead to a lack of self-control. Drinkers of alcohol may not realise how much they are consuming, and fall ill as a result. They may become unconscious, and may even fall into a coma.
Long-term effects of alcohol include damage to the liver and brain. Alcohol may also cause weight gain, and it is addictive.