Addiction is a strong, uncontrollable need to take drugs, drink alcohol or carry out a particular activity such as gambling.

It becomes the most important thing in your life and leads to problems at home, work and school.

There's no single reason why addictions develop. Regularly drinking alcohol or using other substances, or spending time gambling or on the internet (including porn sites), may be pleasurable or relaxing. Some people experience these feelings particularly intensely and have a strong desire to repeat them more often.

You're more at risk of developing an addiction if:

• other members of your family have addiction problems
• you experienced stress or abuse while growing up
• you have mental health problems