system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why have my dreams become more vivid/realistic since I quit smoking marijuana?
gpt
Yes, smoking marijuana does affect your quality of sleep, namely it hinders your body’s ability to produce REM sleep (the stage where intense dreams usually occur). Smoking before sleep will alter your sleeping patterns, thus altering your dreams.

In 1975, Feinberg, et al. did a study on the effects of THC on REM sleep patterns in human subjects. They had this to report:

Electroencephalographic readings and eye movement were recorded in experienced marijuana users under placebo and tetrahydrocannabinol (THC). Four subjects were studied for 3 baseline nights, 3 nights under initial dosage of 70 mg/day, the last 3 nights of a 2-wk period of 210 mg/day, and the first 3 nights of withdrawal. Three other subjects were studied only during the latter 2 conditions. Administration of THC significantly reduced eye movement activity during sleep with rapid eye movements (REM) and, to a lesser extent, the duration of REM itself. Withdrawal led to increases above baseline in both measures but the “rebound” effect was greater for eye movement. Stage 4 sleep tended to increase on drug, but this effect was not statistically significant. On withdrawal, stage 4 sleep decreased significantly; this change was marked only on the first withdrawal night. The functional or biological significance of these changes is unclear. Nevertheless, these are the most marked effects of THC on brain electrical activity demonstrated thus far.

Smoking marijuana may alter short-term memory. Short-term memory is integral to recalling your dreams as your wake up.