With regular use, people can develop a mild tolerance to cannabis. This means they need to take more and more to get the same effect.
Dependence on cannabis can be psychological or physical, or both.
People who become psychologically dependent on cannabis find that using cannabis becomes far more important than other activities in their life. Cannabis becomes part of their lifestyle (eg reducing stress, increasing relaxation) and some come to depend on it. Some people crave the drug and find it very difficult to stop using it.
Physical dependence occurs when a person's body has adapted to a drug. The body is used to functioning with the drug present. Heavy and frequent use of cannabis can cause physical dependence.