Yes that is true! I did a little extra digging and found some more studies. This one, 'Pharmacological REM sleep suppression paradoxically improves rather than impairs skill memory', found that SSRIs did not, in fact, affect the creation of new memories. The study 'Sleep and cognition at baseline and the effects of REM sleep diminution after 1 week of antidepressive treatment in patients with depression' similarly found 'no negative effects of a decrease in REM sleep on memory performance in patients taking antidepressants' in their study using SSRIs and SNRIs. Both studies here may imply that new memories can be created during sleep even in the absence of REM sleep.

>I'm not sure there's been any studies regarding long term use of specific drugs on memory, but there could be some out there.

Here is an interesting one