Substance abuse is over indulging or becoming dependent on drugs or other chemicals which leads to physical and mental health problems.

The most common substance abuse is with alcohol. Most people drink sometimes but there are some clearly defined 'safe' limits which are 21 units of alcohol per week and no more than four units daily for men. And 14 per week or three units daily for women (although pregnant women shouldn't drink at all). Drinking above this 'safe' limit is known as 'heavy' drinking and can be hazardous to your health. Heavy drinking can increase the risk of certain diseases such as cancer, heart problems, liver and pancreas damage. Drinking heavily despite having caused physical or emotional problems to those close to you is a sign of alcohol dependence. This can be a serious addiction where you will drink every day and if you can't drink then you experience painful withdrawal symptoms.

Substance abuse can also include the misuse of drugs like heroin, cocaine or cannabis. Drugs taken for recreational purposes are will affect you differently depending on your location and mood. For some problems will occur immediately whereas others develop a tolerance to a drug and need to use higher doses to get the same effect. There are several different categories of drugs each with divided up according to the effects they have on users;

Stimulants - Such as caffeine, tobacco, amphetamines, cocaine and ecstasy. They increase brain activity by acting on the central nervous system. Users feel confident, alert and stay awake for much longer. Steroids, aerosols and glue also fall into this category.
Depressants - Such as Valium, temazepam and cannabis. Again these act on the central nervous system and reduce brain activity. Users feel relaxed and less tense but also have impaired mental and physical capabilities.
Analgesics - Such as heroin, opium and codeine. These produce feelings of warmth and reduce users' sensitivity to pain.
Hallucinogens - Such as LSD or 'magic mushrooms'. Hallucinogens increase sensations and can distort the way users see and hear things.

Less commonly substance abuse can include drinking large amounts of coffee or smoking cigarettes.

The reasons leading to substance abuse are as varied as the individual but there are several commonly reported reasons. Substances are often used to try to cope with problems in life but the feelings of relief these provide are only temporary and through constant use you risk becoming dependent on them.