Class is right, any smoking is bad for you.
I learned about this in my Psychology class;
Essentially there's a spot in your brain called the hippocampus, and it holds receptors.
Over time, smoking wears down and destroys these receptors. Also, a large concentration of these receptors in hippocampus may partly explain why marijuana impairs memory.
Other effects:
- adjusts and enhances mental activity.
- possibly alters your pain perception.
Also, cancer patients undergoing chemotherapy report that marijuana is effective for overcoming nausea. But the medical use of marijuana is controversial because the possibility that chronic use can cause health problems or lead to abuse of it.