Psychotropic medication can cause changes in REM sleep. Lack of restful sleep (sleep deprivation) can cause psychosis.
It may be helpful to have a sleep study conducted to determine if there are any sleep conditions present.
In the event that there is a sleep disorder such as REM sleep disorder, the neurologist conducting the sleep study, can suggest something to improve it.
Poor sleep/lack of REM can impair one's memory and other cognitive functions.
There are different neutotransmitters associated with memory - dopamine, norepenephrine as well as hormonal changes, thyroid malfunction and lower b vitam levels. Besides a sleep study, your physician may want to rule some of these out as well.
There are some natural options used to improve memory such as Pregnenolone, Piracetam 800, DHEA, use of GAMMA brain waves hemisync audio stimulation
It seems that you're off line now. Feel free to reply when back on.