I mean it CAN be pretty dark traumatizing for sure (see Fear and Loathing in Las Vegas, especially the White Rabbit scene), but either way, when you’re tripping on LSD, you definitely WILL notice that something’s not right. Wild visual and auditorial hallucinations, vibrant colors and rainbow patterns, up to and including synesthesia (i.e. seeing sound and hearing pictures) are all known to occur.

Even at a low dose it produced noticeable mood changes, though usually no hallucinations.