Hello! Like most research done in the cannabis field, the effects of cannabis on sleep cycles is still in its infancy and requires more research to make some solid arguments. That being said, the studies on cannabis and sleep that were conducted in the 1970’s did show that varying levels of THC decreased the amount of REM sleep that participants experienced. We know that a lot of our dreaming is done during the REM sleep cycle, so there has been some correlation made between the use of cannabis with a decreased occurrence of dreaming. Again, we should keep in mind that the evidence is limited, and further research is required, along with a better understanding of its clinical implications.
Check out this article by one of the contributing writers at HelloMD. It goes into more depth about this topic: