Substance abuse covers misuse of a range of mind-altering substances. It can have a severe impact on your functioning as well as your physical health.

Substance abuse or misuse is formally defined as the continued misuse of any mind-altering substance that severely affects person’s physical and mental health, social situation and responsibilities.

Alcohol dependence is the most common form of substance misuse, but any drug, including heroin, cocaine, crack and cannabis, comes into this category, as does the misuse of glue and aerosols.

Substance abuse may also include smoking cigarettes or drinking excessive amounts of coffee. Although not strictly a form of substance abuse, the eating disorder bulimia nervosa does involve the misuse of food.

Most forms of substance abuse may give you a temporary feeling of well-being or of being in control, but all of them can ultimately damage your health.

The most severe forms of substance misuse are normally treated by specialist drug and alcohol rehabilitation services.

For people with mental health problems who are also substance misusers, the mental health team normally encourages contact with a specialist substance misuse service for help. There is also a lot you can do to help yourself.

What leads to substance abuse?

There are many reasons why you may start to use any of these substances. You may begin because of curiosity, rebellion, or influence from peers. You may find the experience enjoyable and want to repeat it. It may start when you are unhappy or stressed or trying to cope with problems in your life.

Drugs, alcohol, nicotine, solvents and even food can start as ‘props’ to help you get through difficult times. But the feelings of relief are only temporary and, as the problems don’t disappear, you may use more and more of these substances and risk becoming dependent on them – which in itself creates new problems. 

Types of drugs

All drugs can be divided up according to the main effect they have on users.


Stimulants include caffeine and tobacco as well as amphetamines, anabolic steroids, ‘poppers’, hallucinogenic amphetamines (ecstasy), cocaine and crack. They act on the central nervous system and increase brain activity.

Users generally feel more confident and alert, are able to stay awake for longer and can perform physical tasks for a longer period of time. High doses can cause nervousness and anxiety 9except for tobacco). Stimulants can also cause temporary feelings of paranoia (except for tobacco and caffeine).


These include minor tranquillisers such as Valium, Librium, Mogadon and temazepam, solvents, glues, aerosols and gases.

Depressants act on the central nervous system and slow down brain activity. They relax you, making you feel less tense and anxious, but at the same time impair mental and physical activity and decrease self-control.


Analgesics are painkillers and include heroin, opium, pethidine and codeine. They make users less sensitive to emotion and physical pain and produce feelings of warmth and contentment.


These include cannabis, LSD and magic mushrooms. Hallucinogens act on the mind, heightening sensations and distorting the way users see and hear things.

Food - Bulimia nervosa

People with bulimia nervosa can’t stick to a healthy eating pattern. They tend to binge, that is, eat a lot at once.

Find out more about bulimia nervosa.


You may smoke tobacco to help you relax or you may feel that smoking helps you cope with stress, but the health effects of smoking are very serious.

Long-term smoking causes cancer and heart and lung disease and also damages the health of other people who are exposed to cigarette smoke.


Solvent abuse (or volatile substance abuse) is the inhalation of fumes from ordinary household products in order to get high. Products that may be sniffed include cigarette lighter refills (butane gas); aerosols (it is the propellant, often butane, that is inhaled); solvent based adhesives (glue sniffing), and petrol.

Most volatile chemicals act as depressants, slowing down brain activity and making users feel more relaxed and less tense and anxious.

They also impair mental and physical activity and decrease self-control. Prolonged misuse of solvents and volatile substances can result in brain, liver and kidney damage.

Signs you may be dependent on solvents

Users may start out experimenting with solvents out of boredom and then move on to using them casually or recreationally. A very small number of users come to rely on them as a way of coping with life – not just to have some fun.