When kristen began to smoke, she only had 3-5 cigarettes. now, for her to feel in control during the day, she has to smoke 18 cigarettes. what is she experiencing?

She is experiencing an addiction process.

Explanation:

Addiction is an acquired mental and physical health disorder that is characterized by periodic or permanent compulsion to perform a particular activity or use of a psychoactive chemical.

The addictive process is characterized by the gradual acquisition of a dependence. Thus, it begins with a mild dose and gradually increases to generate a constant dependence on the addictive object in question. In Kristen's case, she started smoking a few cigarettes a day, but ended up multiplying by six that amount, due to the dependency that she generated.