- Health - addiction to a substance, be it a drug, narcotic or nicotine usually has health consequences. In the case of drug/alcohol addiction there may be mental/emotional as well as physical health problems. In the case of nicotine addiction the problems tend to be just with physical health.
- Coma, unconsciousness or death - some drugs, taken in high doses or together with other substances may be extremely dangerous.
- Some diseases - people who inject drugs have a risk of developing HIV/AIDS or hepatitis if they share needles. Some substances, including specific drugs or alcohol can lead towards more risky sexual behavior (unprotected sex), increasing the probability of developing sexually transmitted diseases.
- Accidental injuries/death - people with a drug/alcohol addiction have a higher risk of falling over, or driving dangerously when under the influence.
- Suicide - the risk of suicide is significantly higher for a person who is addicted to a drug/alcohol, compared with non-addicted individuals. This is not the case with nicotine dependence.
- Relationship problems - social, family and marital relationships can be severely strained, leading to family breakups, etc.
- Child neglect/abuse - the percentage of neglected or abused children who have one or both parents with an addiction problem is higher compared to those whose parents are healthy. These figures apply to some drugs and alcohol, not to just nicotine dependence.
- Unemployment, poverty and homelessness - a significant number of drug/alcohol addicts find themselves without work or anywhere to live.
- Problems with the law - if the substance is expensive, the addicted individual may resort to crime in order to secure his/her supply, making it more likely there will be problems with police, including imprisonment.