Final answer:
Emily is probably experiencing psychological dependence on smoking, which is an emotional need contributing to the habit despite knowing its negative health implications.
Step-by-step explanation:
Emily is likely experiencing psychological dependence when she smokes. This form of dependence is an emotional need for a drug, commonly used to mitigate psychological distress. Unlike physical dependence, which produces physical withdrawal symptoms, psychological dependence centers on the drug craving that is mental or emotional in nature.
With psychological dependence, there can be a condition of tolerance, which is when a user requires more and more of a given drug to experience the same effects. The addictive power of nicotine can be just as significant as more notorious drugs, triggering strong cravings, headaches, irritability, and anxiety when attempting to quit.
In addition, smoking cessation could lead to cognitive dissonance where an individual's beliefs (knowing that smoking is harmful) are inconsistent with their behavior (continuing to smoke), thus causing psychological discomfort.