How vivid can hallucinations actually be?

This year on two television series, characters are hallucinating extraordinarily vivid and elaborate things. One character was absolutely convinced she was having actual sex with a man who is dead, she was amazed because she could hear his heart, feel his heat, lie in his arms. This went on for weeks while she was entirely normal in all other ways.

Another shows a character again experiencing sex, a person following them around and talking to them all day long as vividly as anyone else, and complete detox from drug addiction.

The way the hallucinations are portrayed, these characters are not utterly insane, one has a brain tumor and the other is a longtime Vicodin addict. Both are doctors. Under any circumstances at all, do people really and truly experience that degree of realism in a hallucination? And come to think of it, is there any way to know the answer to this question, since maybe people with severe mental illness or brain trauma actually do. But as far as we know, how real can the unreal ever truly be?

FTR: I have "hallucinated’ some pretty vivid things back when I was dropping LSD as a kid, but even then I pretty much knew it was just some wackitude, it was more in my head than really really really in front of me, such as lying on the couch facing the back and “hallucinating” my mother standing behind me. BEHIND…not really seeing. Just vivid imagining. Same thing with my “hallucination” that I was looking at my girlfriend with a “scream” expression on my own face, when she reports that my face was completely expressionless.

The only things I’ve ever “seen” were more alterations in my perception of what actually existed, rather than something that did not exist in any way, such as looking at the scuff marks on the floor and perceiving them as floating above the floor instead, like mist, and being surprised when someone walking on/through them did not disturb the “mist”.

I’ve never actually seen something which did not exist in any way or on any level, that was completely imaginary. Have you?

There is already a recent thread on just this topic Hallucinations -- how "real" are they? - Factual Questions - Straight Dope Message Board

I guess a lot of Dopers watch House.

I gave an detailed answer to essentially the same question, and several other people contributed insights and accounts of their experiences.

In short, no, the depiction of hallucination in the recent House episode (like most movie and TV depictions of hallucination) was not at all realistic.

I will add one point. Vividness actually has rather little to do with whether or not a hallucination is mistaken for reality. People sometimes have very vivid experiences (especially, but not only, if they are on hallucinogenic drugs) that they easily recognize as unreal, and, conversely, hallucinatory experiences that are quite vague and ‘dim’ are sometimes taken to be realities (whispering voices, and things like that). People generally only confuse things they are imagining (vividly or not) with reality if their minds are badly confused anyway, for one reason or another.

I once had a reaction to allergy medicine where the hallucinations were really vivid. I saw an infestation of bugs that I thought was real. Initially I didn’t know I was having a medicinal reaction, so I can’t say for sure whether I would have thought they were real if I’d seen the same thing on LSD or whatever.

The key to the state of mind you’re typically in when you’re hallucinating is that you’re really not in a position to judge how vivid things are. It’s like when you’re dreaming. Sure, dreams can seem very vivid. But in large part it’s because you’re totally out of it to start with.

Certain potent drugs can supposedly cause extremely vivid hallucinations. I haven’t, and wouldn’t try them.

Check out Datura (Jimson Weed) and Belladonna (Nightshade). Fascinating and sometimes downright scary stuff if you read the “experiences” section. These plants are much stronger than the common hallucinogens (i.e. LSD, shrooms).

Vivid, vivd, vivd. On LSD you see kaleidoscopic graphics or animated collages, not just colorful abstracts, but imagery from nature (esp. dangerous animals like snakes, spiders, and dragons, often confronting you directly). You can also see a lot of imagery from traditional cultures (Meso-American–i.e. Aztec–imagery is reportedly very common). You see wise, benevolent faces and can insert yourself into scenes from people’s lives long ago.

As for the Experience, a psychedelic trip is like an initiation scenario. First they lure you in with spectacular graphics, then they try to scare you with snakes or monsters or Satanic imagery, they they try to tempt you into thinking you can develop magic powers or can sell your soul or that you’ve been tapped to become a new messiah.

But if you humble yourself and realize it’s all in your head and defer to Higher Powers, you can see the legendary Tunnel of Light. It’s like being born again.

Huh, you too? I didn’t know this was common and never mentioned it much because of the silliness of it, but when I was 17 on an acid trip I became absolutely convinced of the fact that I was, indeed, the messiah. :smiley:

But regardless, LSD trips are pretty tame in the sense of the hallucinations not appearing to be “real”, distinct objects but more like transmutations of objects already existing in the surroundings. Check out my links above about Datura and Belladonna… those supposedly can cause “real” hallucinations that come from nowhere and seem absolutely tangible and encompassing. For example, some of the experiences describe a scene such as: you are sitting in your living room one moment and on a beach lying next to your dead grandmother the next. That doesn’t happen on acid.

Oops, we’re a bit behind you and I didn’t know about the brain tumour! Good thing I’m not an avid fan, no harm done.

Huh, thanks for that link. Years ago I read in Discover magazine about someone who took jimsonweed and saw leprechauns everywhere. This was said in the article to be a common side effect. It was the April issue and I’ve never quite been sure if that article was their annual April Fool’s joke. Guess it wasn’t.

I dunno about hallucinations, but my own personal (anecdotal, natch) experiences with dreaming tell me that I can have very, very vivid dreams that, on retrospect, make no damn sense after I wake up and think about it.

Sounds to me like that is basically going into a dreaming state. My guess is that while on the beach with granny they would be oblivious to anything actually going on in the living room.

As for seeing leprechauns, well you might, but you are not going to be seeing them while your mind otherwise seems clear and everything else in your surroundings seems normal (which was pretty much how House was depicted as seeing Amber).

A friend of mine “saw” a dragon, an Asiatic, snake-like dragon come into her hospital room through one wall and leave through the opposite one. It was morphine induced, and she was well aware that it wasn’t real. But she still says she saw it.