Opinions - Does What You Fear Manifest As Hallucinations?

[Eridani]

Hi all, new to the forums. I just have a few questions. I have read through the rules and did my best to search for this topic, and didn't quite find the answer I wanted.

So SWIM is thinking about taking sleeping pills for a trip. It would be his/her first time with any sort of hallucinogenic drug. He/she read the reports at Erowid and found that a lot of people reported seeing, of all things, spiders.

Now SWIM is really afraid of spiders, and is afraid that taking enough sleeping pills to trip might produce rather...undesirable results.

So I guess the real question is with diphenhydramine is...does what you fear most come out in hallucinations? Or what you're thinking about at the moment also manifest as a hallucination? It's a silly question I know, but an answer would really be helpful. Like, cause, SWIM is prepared to see a few unpleasant things, but doesn't want a totally bad trip. Thanks in advance.