Each week thousands of people in the UK take drugs recreationally, and although there are potential long-term consequences, they are able to carry on with the rest of their lives without any problems. However, for some people, drug use can get in the way of work, studying or family. Often, they won't realise the damage their drug use is doing.

Defining drug misuse

"People define drug misuse in different ways," says Andy McNicoll from DrugScope. For him, "It's the point at which the use of legal or illegal drugs becomes a problem by negatively impacting on a person's life. Individuals can experience social, financial, psychological, physical or legal problems at any stage or level of drug use."

For Colin Stewart, Drugs Advisor at Release, drug misuse is, "When the drugs use you, rather than you use them."

He says some tell-tale signs might be:

• Avoiding non-users
• Thinking being stoned makes you more interesting and confident
• Feeling uncomfortable in company or alone without drugs
• Losing weight - it feels good at first but then you avoid food and sleep becomes an issue
• Lying or just not being honest to friends, family and yourself about how often and how much you're using
• Getting in debt or spending large amounts of cash you can't afford on drugs
• Getting credit from dealers, avoiding paying bills, borrowing from mates and family and not telling them what the money is for, or making excuses as to why you need money
• Being especially nice to people who have substances on them, going out with dealers or those with access to drugs who you do not really like and selling yourself for drugs (flirting for drugs)
• Starting to sell belongings or stealing from mates and family - clearly, this is when things are really getting bad

Seeing such changes in a friend can be worrying, although you shouldn't jump to conclusions. As Andy points out, "It's important to remember that these things could be caused by other issues in someone's life and don't necessarily result from drug use."

Types of addiction

Substances such as heroin, benzodiazepines and alcohol can cause your body to develop a physical addiction. If you get aches, tremors and sweating when your body is not getting these drugs, you may be going through withdrawal. You should get in touch with your local drug or alcohol treatment service for help, support and advice.

Although other drugs, such as cannabis or cocaine, may not be physically addictive they can lead to 'psychological addiction' - when you feel unable to function without using them or experience feelings of withdrawal when you stop.

"Beyond physical and psychological effects it's also important to consider the potential financial and legal problems associated with drug use," says Andy. "Maintaining a drug habit, whether legal or illegal, can be costly and lead to problems with debt. Being caught in possession or testing positive for the use of illicit substances can have legal implications. The drug use may also impact on your relationships, or social,  school, or work activities."

Helping friends who misuse drugs

If you are worried about your friend's drug use or think that they are acting strangely, talk to them about what is going on in their life. Trying to spot signs and symptoms of drug use is no substitute for good communication.

"Talk to friends with problems and let them know you miss the real them," advises Colin. "Tell them they aren't fun when they're off their head, and point out gently what they are becoming."

Both Andy and Colin recommend that you offer support and suggest services that may be able to help them.

Thanks to Drugscope and Release for help with this article.

Updated: 26/04/2011