• Strong desire for certain substances ( known as craving).
• Reduced control over the consumption in terms of consumption style and quantity.
• Development of tolerance resulting in an increase of dosage
• Occurrence of physical withdrawal symptoms
• Restricted behaviour pattern
• Denial of addiction
• Neglect of family, friends, job and interests
• Neglecting other aspects of life for the sake of addiction
• Continued use despite obvious consequential damage (physical, psychological and/or social)

One speaks of dependence when at least three of the above criteria occur in an individual over a period of one year.