When you are addicted, for example, to the use of alcohol, drugs, smoking, sex or gambling, you are (physically or mentally) dependent on this use or behaviour. You get withdrawal and/or tolerance symptoms when you don't use the substance. Tolerance means that one needs higher quantities of a substance over time to reach the desired effects.

Withdrawal symptoms are unpleasant physical reactions that occur when the use of the substances is decreased or discontinued. These symptoms range from nausea, muscle aches and fever to concentration problems, insomnia, anxiety and unpleasant dreams. But, also people who do not experience tolerance and/or withdrawal symptoms can be dependent on the substance. They repeatedly and with no success try to reduce or control the use of the substance, or they use it longer or more than they had intended. Obtaining the substance, using it and recovering from the effects of the substance takes a lot of time. They neglect important activities like work, school or social contacts, or completely stop these activities. One characteristic of dependence is not being able to control the use of the substance or to stop using it. There is a certain pressure, an almost irresistible need to use the substance.

To be able to determine if somebody is addicted, the person must meet certain conditions that have been determined by the World Health Organisation (WHO), amongst others.

The following are conditions for dependence; you only have to comply with a few to be considered dependent:

• Tolerance (need more to still feel the effects).
• Psychological dependence (desire, varying from very little to very severe).
• Withdrawal symptoms (get all kinds of physical reactions after you stop).
• Use the substance or carry out certain behavior to reduce the withdrawal symptoms.
• Failed attempts to control the use or the behaviour.
• Spend a great deal of time on the use or the behavior or on recovery of the use or the behaviour.
• Damaging effects due to the use on the addicts themselves and people in their environment (problems at work or school, arguments with people around the person, illnesses, dedicate less time to hobbies).
• Use more frequently and in higher doses than planned.
• Continue to use even if you know it is damaging for you.