Do dreams occur every 90 minutes?

Understanding REM Sleep and Dreaming

The REM (Rapid Eye Movement) stage of sleep typically begins approximately 90 minutes into the sleep cycle, with each subsequent REM period becoming progressively longer as the night continues. Initially, the first cycle may last around 10 minutes, while the final REM cycle can extend up to an hour. It is during the REM phase that dreams, nightmares, and occurrences of penile or clitoral tumescence take place.