Answer:
The answer is: Addictive drugs produce a biological or psychological dependence in the user so that withdrawal from them leads to a craving for the drug that, in some cases, may be nearly irresistible.
Explanation:
These drugs create a constant stimuli in the brain in places responsible for the pleasure and stimuli response. The constant use of these drugs create new pathways in the brain and alterations of the common function of neurons. As the amount of "feel good hormones" increases over time it generates a tolerance threshold that is pushed back constantly causing the anxiety of "wanting more".
