Drugs, Smoking, Alcohol

They affect the CNS and can lead to addiction. 

People get addicted as it gives them a sense of well being that they crave or the body gets used to its affects.

Painkillers: Deaden pain/ change how we think about it. Morphine.

Hallucinogens: Produce sensations of false reality. LSD, cannabis.

Stimulants: Increase speed of our reactions. Caffine.

Depressants: Slow activity of brain and reaction times. Alcohol. 

Painkillers block the release of neurotransmitter into synapses. 

Stimulants enhance the release of neurotransmitter.

Cigarettes contain:

Carbon Monoxide: Reduces amount of oxygen red blood cells carry.

Nicotine: Raises blood pressure and increase risk of heart disease.

Tar: Causes cancer (contains carcinogens) and collects in lungs that cause emphysema.

Alcohol abuse can cause liver disease, brain damage, cancer and raised blood pressure.

Sex, age and body mass affect how long it takes for your body's cells to break down the alcohol. 

4 units a day for men. 3 for women. 

A pregnant woman who drinks regularly increase risk of the baby developing abnormally.