Pharmacology.
For this discussion, choose at least two different areas of pharmacology and discuss the process by which the drugs work in those areas. Your post should indicate that you know and understand the process, but you should add to that by discussing how this might apply to drug use and addiction. For example, you may want to discuss what is it about drugs that affect the brain function or chemistry that cause people to want more and more, or any other area you choose to discuss.