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. 
Coffee, tea and chocolate all contain caffeine. It is also added to some soft drinks and energy drinks as well an ingredient in some painkillers and cold remedies. The average cup of coffee contains around 40mg of caffeine per cup, a can of cola around 23mg, and some energy drinks have four times that amount. Plain chocolate has 40mg caffeine per 100g – nearly three times as much as milk chocolate

Signs you may becoming dependent on caffeine

Caffeine stimulates the brain and nervous system. It can make you feel more alert and better able to concentrate, and it also increases acid production in the stomach, which helps digestion. If you regularly drink large quantities of caffeine – say, five or more cups of coffee a day – you may find your tolerance has increased and you need to drink even more to get the same stimulant effect.

The disadvantages of caffeine are that it increases your heart rate and blood pressure and makes you pass more urine – so you may end up losing calcium if you have too much. Sensitivity to caffeine varies from person to person, but too much can make you anxious, restless, irritable, jittery and sleepless. It can also give you headaches, stomach pain, nausea, muscle twitching or palpitations.

Tips to help you cut down on caffeine

Cutting out caffeine in one go can be difficult because you may experience withdrawal symptoms, including severe headaches as well as nausea, anxiety, fatigue and depression. One way to avoid this is to gradually decrease the amount of caffeine you consume, either by drinking fewer cups of coffee each day or by gradually switching to decaffeinated coffee. It’s important not to switch to other substances that also have high levels of caffeine, such as cola or chocolate.

Medicinal drugs, such as tranquillisers and sleeping tablets, may have been prescribed for very good reasons, but they can also cause health problems if used for long periods. Tranquillisers are thought only to really help anxiety for about a month and sleeping tablets are only effective for a couple of weeks. After that time you may find you need a higher dose to get the same effect and even then your anxiety may increase or your sleeplessness return.

Street drugs, such as cannabis or ecstasy, are usually taken for recreational purposes. How they affect you will depend on the type of drug, your own physiology, the amount you use, your mood and your environment. For some people, the first hit can cause problems, especially if the drug contains impurities. For other people, the problems may start as their bodies get used to the repeated use of the drug, and they need higher and higher doses to maintain the same effect.

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.

Signs you may be becoming dependent on drugs

If you rely on drugs to help you feel less anxious or depressed or to improve your mood, you may be becoming psychologically dependent. If you rely on drugs to achieve certain physical effects or you can’t face the unpleasant physical effects of not taking the drugs, you may be becoming physically addicted. In fact, most drug-related problems generally involve physical and psychological symptoms and sometimes it is difficult to separate the two.

Other signs that you could be becoming dependent on drugs are:

if obtaining and taking drugs are more important than anything else in your life

if you use drugs to block out both physical and emotional pain

if you use drugs to distance yourself from problems such as loneliness, family or relationship problems, low self esteem, poverty or housing difficulties, unemployment or lack of opportunities.

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. This makes them feel guilty and out of control so they then panic and punish themselves by starving, making themselves sick, taking laxatives or over-exercising. This can lead to a number of physical problems including tooth decay, constipation and intestinal damage, as well as heart and kidney disease. Tell-tale signs of bulimia nervosa include making excuses to avoid eating in company or rushing to the lavatory after a meal.


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.

Find out more about smoking and how to quit.


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.