Dream suppression
Dream suppression can be described as a cognitive component which partially to entirely interferes with the REM dream stage in the dream cycle or suppresses recollection and retention of the dream in short term memory.
This can decrease the percieved frequency and vividness of an REM dream state, leading into a complete lack of ability to recall any details about the dream. This can be the result from one of two different effects, directly effecting the REM dream cycle and indirectly by partially or completely eliminating short term recall of a dream. The first of which can result from use of cannabinoids such as THC before sleep and the latter from depressants such as alprazolam.
Psychoactive substances
Compounds from our psychoactive substance index which our may cause this effect include: