the body needs a constant supply of the drug
Addiction!
Tolerance to a drug (so that higher and higher amounts are needed in order to obtain the same initial effect) and dependence - both are part of the physical addiction. Psychological addiction does not involve physical tolerance and dependence, but can be difficult to treat, unless there is motivation to kick the habit.
There really are no needs met. Some people just think it will relieve them of stress or make their lives much easier. Please don't do drugs. It will come back to bite you. ;)
Dependency / Addiction
Drugs usually have a physical addiction, which means if you don't have that drug, your body thinks it's not functioning properly. The addiction can make an individual do anything to get that drug. Some people would even kill their families to get money if they needed drugs.
Dependency / Addiction
Nicotine is the highly addictive drug found in tobacco. It has been said that nicotine addiction is one of the hardest addictions to beat, acting in a similar way as heroin or cocaine addiction.
addiction
There is actually no such thing as an uncontrollable addiction to a drug.
it means they feel like they physically need it
drug abuse could lead to drug addiction and dependence
Dependency / Addiction