Frequent use causes some lung and throat irritation.
Your nose and mouth tubes connect, then the single tube (trachea?) branches into the bronchial tube to your lungs and the esophagus to your stomach.
Marijuana cannot cause psychological problems alone, but it can speed or exacerbate their onset in those that have a pre-existing propensity for them.

BUT- You just have paranoia. It might be the strain, it might be the amount, but just try to stop smoking before you get there.