Cataplexy without narcolepsy is very rare. Cataplexy is caused by the same thing as narcolepsy; different aspects of REM sleep invading into your day.
It's a manifestation of the muscle paralysis that keeps you from acting your dreams during normal REM sleep.

From my understanding cataplexy is the muscle control part of narcolepsy. In other words wen a person goes to sleep the muscles go to sleep as well. Becus our bodies cnt tell the difference from day an night so we have muscle give outs… triggers thru emotions…sign that yur body is need of a nap

the answer is yes. You can have even narcolepsy without cataplexy, and as it has been my case, developped cataplexy sometimes partial or full ( as per myself) years after the first effects or bouts of narcolepsy attacks. I live since almost 60 years with that medical condition, which started at 5, as I have almost 65. So I saw and experienced a lot around that debilting disability.

The short answer is 'yes'.
Here's a couple things you may want to read and hopefully they may give you some insight and direction. The first article has an abstract- a short summary of the full article (which is written in researcher-speak 😸) from the National Institute of Health (NIH), a vast library of research and studies covering just about any human affliction. The second article covers a lot of things you probably already know from your own experience, but hopefully may offer new info for you. My best wishes for you! Jeff4

https://pubmed.ncbi.nlm.nih.gov/31427075/

https://www.healthline.com/health/cataplexy-wit...

If you are experiencing weakness in your muscles that can cause you to end up on the floor and they do not diagnose Narcolepsy, Type 1, then I would recommend the docs rule out seizure activity. There are some types of seizures that mimic cateplexy.