My take on this (please discuss and add anything that I may have missed:
Cannabis can trigger early psychosis and schizo-affective disorders and a percentage of the population as it does with some that have a dependence that is psychological (and withdrawal symptoms that causes physiological issues such as negative body load + mood swings and it also triggers sleep and dreaming disorders).
But I like smoking pot HOWEVER my Endocannabinoid receptors have learned to seek out and mitigate (homeostatically regulate) the effect of Cannabis so if I start smoking, say for example I start in the morning (after having had any for a YEAR), I will be straight by the end of the day !