Hallucinations, by Oliver Sacks

[rachelmanija]

A book on hallucinations which are not caused by schizophrenia and other psychotic disorders. (It also doesn’t deal much with culturally normal hallucinations, which is too bad.) Hallucinations – sensory perceptions which occur during waking and are not based on consensus reality - are surprisingly common, and include many experiences which probably most people don’t think to define as hallucinatory.

While drifting off to sleep, with my eyes closed, I often see kaleidoscope-like geometric patterns, faces (often grotesque or witch-like), and occasionally swarming insects. They are not dreams, are not perceived as being part of reality or projected into the real visual field, and do not have emotional connotations. I always assumed they were caused by going from visual perception to blank darkness while drifting toward sleep: a sort of meditative optical illusion/visual imagination.

They are called hypnogogic hallucinations and are extremely common, and the particular things I see are commonly seen, along with other stereotyped visuals. (“Stereotyped” as in common to people who experience the phenomenon, as opposed to “unique.”) They are caused, in simple terms, by the visual centers of the brain “idling” before sleep.

Hypnopompic hallucinations are less common, and are more vivid, often briefly perceived as real, often frightening illusions which occur upon waking from sleep. I've had those too, thankfully only a few times; mine were quite unpleasant, full-sensory illusions of being entombed in stone. They were not nightmares, though; I could also see my real surroundings. Once someone in the room with me verified that I had my eyes wide open and could track movement and respond to voices.

I have also sometimes, while wide awake, heard my name being called, when no one is there or when nobody called it. This is also extremely common. People in dangerous situations often hear voices giving helpful commands or suggestions; grieving people often see or hear their loved ones. These phenomena are common and “normal.”

I wish Sacks had analyzed those situations more in neurological terms, because I find that fascinating. The main theory he suggests, regarding auditory hallucinations in general, is that they’re a glitch caused by the brain failing to recognize its own thoughts. Another possibility is that people become consciously aware of the non-verbal stream of consciousness beneath their articulated thoughts, and perceive it as coming from the outside.

Sacks covers a number of hallucinatory experiences caused by neurological conditions, such as Charles Bonnet Syndrome, in which blind people hallucinate certain types of sights. Also, in a fairly funny chapter, his own youthful drug use.

The non-psychotic hallucinations are typically either never experienced as “real,” or are easily believed to be unreal once someone explains that they aren’t real, or are understood to not be real once they’re over. This is quite different from psychotic disorder-type hallucinations, which are often believed to be real, even when they end. (A person with PTSD may hallucinate, but they typically either always know the hallucination isn’t real, or, as in the case with flashbacks, figure it out in retrospect.) Regarding culturally normal hallucinations like ghosts, people may believe that they did literally see a spirit, but they also regard it as a spirit – a visitor from another realm. That’s a different experience from literally believing that Abraham Lincoln is living in your guest bedroom. (To avoid wank, let’s assume that I am only discussing those perceptions of spirits, God, etc, when they really are hallucinated and not objectively real.)

Hallucinations without accompanying delusions don’t usually cause major life problems for people. They are not “crazy,” though they might worry that they are. Delusions seem to be what cause the life problems.

The book is well-written and intriguing, as one would expect from Sacks, but more descriptive than analytical. Some types of hallucinations, particularly visual ones with a clear-cut neurological basis such as migraine auras, are explained in neurological terms, but others are simply described. The descriptions are quite evocative and the material is fascinating, but I would have liked more neurological speculation, especially on why certain situations or conditions create certain types of hallucinations, like fever deliriums causing distorted perceptions of size, which are almost invariably perceived as unpleasant or threatening.

I also wish he’d covered auditory hallucinations in more depth. At times he speculated on historical figures who might have heard voices. The problem is, many people write about the simple perception of their own thoughts in voice-like terms, so it’s very hard to tell whether someone literally meant they heard a voice, or only that their thoughts were so vivid that they seemed voice-like. It seems entirely possible, too, that two different people might have a neurologically identical experience, but one might attribute it to an outside voice and one to distinctive inner thoughts.

Please discuss your own experiences of and theories on hallucinations, if you wish.

Hallucinations

Comments

[loligo]

I get awesome hypnogogic hallucinations when I stay up too late -- usually this happens when the person in bed with me is trying to continue a conversation, or trying to encourage other bed-centered activities, when half my brain has already fallen asleep. So I usually announce them ("Hey, I just saw a bunch of Vikings sitting around a big oak table eating porridge!"), and then Andy asks whether I'd rather fall asleep all the way or try to wake back up for a while longer.

(Yes, that is an actual example.)

[oyceter]

Best!

[oyceter]

I always feel like I can see the little microbes floating in my eyes if I focus just right.

I'm also curious about the line between dreams and hallucinations! Mostly because if I'm really tired, I'll start seeing things at times, but I have always thought that it was my slipping off into sleep.

[badgerbag]

Do you mean regular "floaters" or sort of tiny moving geometric patterns? I can't remember what the patterns are called but there is a name for them and there's a thing at the Exploratorium that shows them to you if you look into it!!

[badgerbag]

I get the auditory ones sometimes. It's very strange! Sometimes it's someone I know saying my name, but other times it's a completely strange voice, saying a word or a short nonsense phrase. And I know I didn't hear it with my actual ears, but it is as real sounding as if I had. It's very dreamlike. I had it a lot while I was ill with a fever a couple of years ago. Other than that, it usually happens as I'm trying to fall asleep but am still conscious.

[rachelmanija]

Yes, Sacks talks about that. A lot of people experience that.

[mildred_of_midgard]

From personal experience, I can speak best to falling-asleep hallucinations. I see geometric patterns, but not faces or insects (thankfully to the latter!). More often I get auditory hallucinations when I'm falling asleep, consisting of a voice talking with indistinct words. It's always a voice I heard talking a lot during the day--when I was growing up, it would be my mom's voice; when I was in college, it would be the sound of one of my professors lecturing; now it's likely to be one of my co-workers talking.

I have a theory that my auditory hallucinations have to do with one of the functions that's been posited for sleep: long-term memory formation. I was in college 10 years ago, so this theory could be way out of date. But I suspect my brain is taking the most salient input it received during the day, and re-traveling those neural pathways to reinforce them into long-term memory.

[kore]

OMG, the auditory ones can be SO annoying. I used to constantly hear music -- not like pop songs or music I'd heard before, it was like I was composing -- and it would keep waking me up!

[vass]

My hypnogogia are usually auditory, not visual, although I do get the 'Tetris effect' visual ones when I've been doing a repetitive visual task like playing Tetris.

The auditory ones are usually in the voices of people I've heard in real life that day (whether friends or strangers on public transport) but not saying things they actually said, or often even anything comprehensible.

I get auditory hypnogogia markedly more often and longer if I've had a very people-heavy day. I talked with my psychiatrist about that, and he confirmed that that's because the auditory hallucinations while I go to sleep really are like the Tetris effect: my brain is practising a skill it was working on that day (talking with people) in the moments before sleep. It's part of the learning process.

[thistleingrey]

heh! Sometimes the geometric visuals shade into my dreaming of playing Tetris, even now, and I haven't played any version of it since the early '90s.

[em_h]

I can't remember ever having hypnogogic hallucinations, but I've had a few extremely unpleasant hypnopompic experiences which sound very like yours.

I can only recall one auditory hallucination, during a ballet recital in my early teens, when I very clearly heard an adult voice near me saying, "Well, she's not very good!" I realized later that there was no one anywhere near me whose voice I could possibly have heard so loudly and clearly (not to mention, not many adults would so cheerfully trash a young girl in public). It's funny, because it's far from the most stressful situation I've been in, but apparently the only one where the conditions were exactly right to produce an auditory hallucination.

A very, very few times in my life I've had experiences which I conceptualize as hearing from God. These I don't experience as an external voice, but as, if this makes sense, an external thought -- a thought that comes very suddenly and directly into my mind and doesn't *feel* like it comes from me. Obviously, some part of my mind slightly different than my normal articulated thought process is involved; but because of my particular belief system, I do have some lingering sense that something not-me is also involved. Not in any way provable or necessary, of course, and it can easily be neurologically accounted for without a God-hypothesis. (For the record, on the very few occasions this has happened, it has been offering reassurance of a very deep kind.)

[rachelmanija]

Your ballet hallucination sounds very much like the "failure to recognize thought as a thought" glitch - most likely, a fragment of your inner critical monologue which you weren't even consciously aware of.

I've read a fair amount on the sense of divine presence. Interestingly enough, people using the same research to argue for or against the existence of God. Certain brain activity in certain regions will give people a feeling of divine presence. But whether that means that the sense is merely neurons firing, or whether the neurons exist so that people have the capability of sensing God, is, of course, unanswerable. Like a lot of neurological research, it explains the "how" but not the "why."

[kore]

I have this! I should read it.

I don't have the hypnogogic hallucinations so much -- I get auditory stuff, especially as I'm falling asleep: I think people are calling my name, hear music, think I overhear conversations. There was one frightening thing where I kept waking up, thinking I heard a BANG. Although it's benign, it's called "exploding head syndrome" -- lovely! It went away after a while. I think it's related to stress, migraines, whatever. Sometimes when I wake up I think I hear someone moving around in the room, or calling my name, but that's less common. Sometimes I do get visual stuff, but it's always very muddy and unclear, and usually unpleasant. They're more annoying than anything else.

Does he talk about migraine 'hallucinations'? That was in his book on migraines -- he talks about how maybe saints were seeing migraine paintings, has migraineur artwork, &c. (I find it very disturbing -- I can't look at it for more than a few seconds, or it starts to cause a headache.) I remember the first time I saw the floating glowy checkerboard that's the classic symptom of migraine, in my twenties (in graduate school at the library). I had no fucking idea what it was and thought I was having a stroke. (Interestingly enough some of the doodles I did as an adolescent look just like some migraine art -- spiky, sharp, disconnected little scotoma-like things -- altho it wasn't conscious at all.)

[rachelmanija]

Yes, there's a chapter on migraine auras. Apparently the aura is a literal visual representation of the electrical activity occurring in the brain at the time, which explains why many people see extremely similar types of patterns.

[thistleingrey]

When trying to fall asleep, I get colorful mosaic-type visualizations, not really kaleidoscopic but in a similar vein.

My first striking experience of hallucination wasn't mine--my cousin and I were keeping an eye on her father and a very young relative, and her father told the little boy to gather up the toys he'd left under the table. There were some; when he was directed in some detail to get the frog he'd missed, however, we blinked. At the time my uncle was fairly heavily medicated for complications from Parkinson's (and in his seventies), but he'd seemed lucid till then. Afterwards his physical decline sped up, too.

[rachelmanija]

Sacks specifically discusses Parkinson's. The medications for it can make you hallucinate, but Parkinson's can also do that as a symptom.

[17catherines]

I definitely get the thing with hearing someone call my name.

And one year, when I was particularly exhausted at midnight mass, I had the sensation of being separated from my own body, and heard choirs of angels singing above the organ music. Which was both alarming and kind of cool - if one must have hallucinations, I'm all in favour of seasonally appropriate ones!

Interestingly, after a few moments, I was able to consciously decide that I liked angelic choirs in my midnight mass, and consequently heard them above all the organ solos for the rest of the night. I have no idea what that was about or how I did it - I have a very good auditory imagination, and if I choose, I can 'hear' in my head specific voices singing specific songs, even if those people have not sung those songs in my hearing, but this definitely felt as though the input was external.

Catherine

[marycontrary]

Well, now that you've described your hypnogogic visual hallucinations, it's very obvious that I occasionally have auditory ones: sounds or music that I know isn't real, played in my head. Once it was an orchestra tuning up: I knew it couldn't be imagined, because there were too many different scales and little flubs for me to track at once.

I had visual hallucinations of light and movement when I woke up from an hour's nap after 72 hours awake, but it was lovely, not scary.

Hmm, I'm not sure if this one is a hallucination or what: when I am very surprised, startled awake, or sometimes eat after I've been very hungry, I feel like a surface of sensation travels through me and reflects. A sort of odd sensation that starts at my heart, travels to my left, bounces, and moves across my body to the right, for example. I assumed it was neurochemical, adrenaline shooting through my blood and the sensation being refined a bit into a pattern by my head, but maybe it's just all whichever part of my brain synthesizing a false data on a check in.

[lovepeaceohana]

Hmm. I don't have any very clear memories of events like these. The closest is something that happens to me every once in a while as I am (falling?) asleep - it feels closer to dreaming, though, even though I'm told that dreaming doesn't happen so quickly (within five or ten minutes). What happens is usually that what I think of as my dreaming self is walking, and then stumbles and falls. The sensation of falling is so powerful that it wakes me up all startled and clutching at my sheets; it's almost literally a sensation of having fallen back into my body.

I do sometimes hear things - my children calling for me when they are not, usually - but I think that's less a true hallucination than my brain being paranoid. (Mostly it happens while I am showering, thus: "Is that them crying? That could be crying. Although if it were a real cry it would be much louder." Etc.)

[vass]

I do sometimes hear things - my children calling for me when they are not, usually - but I think that's less a true hallucination than my brain being paranoid.

I've had something a bit like that happen to me: I kept thinking my phone was ringing just out of my range of hearing. I changed my ringtone to a tune that I was unlikely to mistake any other background sound for, and it stopped happening. Needless to say, I have phone anxiety.

I would imagine that'd be a lot more likely to happen with young children, and particularly if you were anxious about taking a shower or something like that, and of course you can't train them to cry a different tune.

[staranise]

The hallucinations I remember best are hella unpleasant. I get primarily tactile/minorly visual hallucinations. Usually, in my younger days, in tandem with an OCD-like set of symptoms. Things like a needle being stuck in my arm, blood dripping down from a place where I'd been touched or hit, a knife being drawn across my skin, or insects crawling all over me. I'd sometimes have to place, and keep, my hand over the affected area for half an hour or an hour, just to prove it wasn't there (since the skin on my arm could feel the point of the needle and the skin being moved by it, but my hand would not feel the syringe or point of insertion; it just felt smooth skin).

[klwilliams.livejournal.com]

I have visual hallucinations in my awake moments while sleepwalking. I tend to go back and forth between the bedroom and the bathroom while asleep (often asleep for only part of the trip), and I'll see cats or more rarely other objects as I try to fill in dark spaces. Weird, but not scary.

[isabelknight.livejournal.com]

That's fascinating! I was also really relieved to read about how common it is to hear voices - I've heard (as in, I would swear that the sound existed, not as in, I had a thought that was like someone else's voice in my head, which I also get from time to time) voices since I was a little kid, but very rarely.

Embarrassingly, right up until I was diagnosed with a mental illness that sometimes presents with auditory hallucinations (in my late 20s), I really thought they might be real. Finding out that these rare but usually funny or comforting visits were just a mis-firing of my fucked-up brain was really depressing. It's good to know that they might have been produced as a part of normal human experience rather than being further evidence of how my specific treacherous brain was trying to mess with me, if that makes sense.

[rachelmanija.livejournal.com]

I'm glad it was heartening! I can't speak for your particular case, of course, but auditory hallucinations are quite common in people without mental illnesses, so even if you do have a mental illness, that may not be what's causing it.

Hallucinations caused by mental illness are typically threatening, frightening, or otherwise unpleasant, not funny or comforting.

[tool-of-satan.livejournal.com]

They are called hypnogogic hallucinations and are extremely common, and the particular things I see are commonly seen, along with other stereotyped visuals.

The only hypnogogic hallucination I get with any regularity (assuming that's what it is) is a sudden bright flash of light and a faint sound - it's very similar to having an old disposable flash bulb go off in your face. I wouldn't mind it except that it tends to jolt me awake.

I can't remember ever having any other hallucinations, although it wouldn't surprise me if I did sometimes when I'm sick and I simply don't recall. I have articulated my thoughts inside my head as speech ever since I was a fairly young child, but it's always my conscious mind speaking, so I don't experience it as an auditory hallucination.

[naomikritzer]

I had never thought of migraine aura as a hallucination, but that would be one. I don't get migraines; I get aura without migraine. Which can still be very annoying. I guess despite knowing it's neurological I can't help but think of it as an eye problem rather than a brain problem.

My splashy, memorable, good-for-telling stories hallucinatory experience was when I was in labor with Kiera. I was in the hospital, because my water had broken but labor hadn't really started yet -- I was having intense but very wide-spaced contractions, mostly 15 minutes apart. I don't sleep well in hospitals (no one does) so they offered me Ambien and at around midnight, the contractions seemed to be tapering off, so I took it.

In between contractions, I would sleep. DURING contractions, however, I would wake up and hallucinate. It was like REM sleep that wouldn't quit even when my eyes were open. I remember a giant plant in the corner of the room with undulating multicolored tendrils. Also, when I was pushing (oh, also: I was really in labor, even though the contractions never got any closer than 10-15 minutes) I saw giant tubular noodles descending from the ceiling. I also reported puppies, teddy bears, and alligators, among other things.

After each contraction I would feel the need to pee, but had to have my husband lead me to the toilet because I was so completely disoriented. (Apparently with the first one I insisted that he ring for a nurse because I didn't think he was qualified to handle this. The floor felt like it was tilted and I was convinced I was going to fall.)

Anyway. Hallucinations are actually a rather common side effect with Ambien (especially if something prevents you from sleeping). On the advice of my midwife I now list it as a drug allergy, even though it's not really an ALLERGY but an adverse reaction.

[swan-tower.livejournal.com]

I've had three or four experiences in my life of napping (it never happens at night, oddly) and thinking that I've decided to get up, but can barely move -- it's like my entire body is made of lead, and dragging myself off the couch is the hardest thing I've done in my life. Then I realize I haven't actually gotten up, so I try again, and again, and again . . . and eventually I actually wake up, and I'm fine. Not your "encased in stone," but almost certainly the same neurological experience, interpreted slightly differently.

And yeah, I agree -- I'd love to know more about the neurology behind such things.

[rachelmanija.livejournal.com]

I have that ALL THE TIME. It's annoying but not scary. I am pretty sure it's not technically a hallucination, but a dream interpretation of being physiologically on the edge of waking, but not quite there yet.

[marzipan-pig.livejournal.com]

I have the 'crazy/scary faces right before sleep' thing, but not all the time. It ALWAYS scares the fuck out of me and has since childhood; I'm finally old enough that I can kind of hang on anyway, like some part of me now thinks 'oh it's that scary thing that sometimes happens right before I go to sleep'. I never really thought of it as a hallucination though I guess it is?

Also with my migraines I'll sometimes get a sense of a scotoma (is there something there or not?) but every once in a while it will turn into SOMETHING, like once I thought there was a little girl there (it's like, sort of the bottom half of my visual field on my left and it's like I can't quite get a handle on if there's something there or not).

Then something about my current meed combo or something means I can't always trust things I read, like, not in a book but more like out in the world (on buses or on ads and usually only ONE word against a bright field), I'll read words in ways that aren't right. This has never happened before and I think it's somehow linked to having FEWER migraines, like as if the scrambly-brain energy gets smeared over more of my day-to-day life. I imagine dyslexia might feel something like this?

[mrissa.livejournal.com]

Heh. If you think he didn't say much about auditory hallucinations, consider how little time he spent on the olfactory ones.

One of the things that's interesting to me is that not only did I not think of what I was experiencing as a hallucination, none of the many doctors I dealt with labeled it as one. At all. And I have to wonder whether the "hallucinations are for crazy people" prejudice is self-reinforcing in part because doctors think, "Oh, I don't want to worry this patient and make her think she is mentally ill, I will not label this symptom a hallucination," thereby reinforcing the idea that hallucinations aren't something sane, stable people have, when in fact they totally are.

[naomikritzer]

I think you're on to something there.

Lyda's mother was having olfactory hallucinations recently (Lyda told me about it after a tense morning in a hospital waiting room with her mother, during which her mother informed her that she smelled funny and she disliked her scented deodorant. Lyda had showered that morning and was not wearing anything scented.) I looked up olfactory hallucinations later and found that they can be caused by anything from a brain tumor to a sinus infection.

[naomikritzer]

Does the book talk at all about synesthesia, and the ways that it can intersect with hallucination? I have an online friend who gets tastes for names, and from what I understand, she actually experiences the taste in her mouth, briefly.

"Naomi" is canned green beans, FWIW. Every now and then people will remember this particular talent and bombard her with names to have her say the flavors for, and Naomi was green beans the first time, canned green beans the second time, so this stuff is noticeably consistent. (And yeah, I asked again not because I'd forgotten but because with a five-year gap I was curious if it would stay consistent.)

Her husband found the picking-a-name process frustrating as hell, because so many names got vetoed on the grounds that she didn't like the taste. And then there were names that tasted good, but she still didn't like the name.

[rachelmanija.livejournal.com]

How cool!

I think Sacks mentions synesthesia but doesn't get into it. It deserves its own book.

The thing about the names is hilarious. Now I want to know what "Rachel" tastes like, and if it's different from "Rachael."

[asakiyume.livejournal.com]

Oh olfactory hallucinations! I once had one maybe?

I was driving home in very bad (snowy) weather, and all of a sudden the car seemed to fill up with sandalwood incense. It felt very portentous. And then it faded. And then when I did finally make it home, I found out that Waka had been burning incense. Oooh, twilight zone.

As for other sorts of hallucinations, I have had visual ones on the verge of sleep, things I think I see, and then I look again, and they're not there. My kids have had the auditory ones--they'll be relieved to hear they're normal.

[jeremytblack.livejournal.com]

I will write about this on my journal sometime in the next couple of days and then email you. This is interesting and I do have some thoughts, but not today.

Does he write about preparatory hallucinations? (That's my terminology, not sure what it would be called.) To wet your whistle about my delusional hallucinatory "daydream" I have, I think it happens because subconsciously I feel I have to prepare for being in a mass shooting situation. So I'll let you know whenever I post that.

[rachelmanija.livejournal.com]

No idea. Do you mean vivid daydreams, or literally seeing, hearing, or otherwise sensing non-existent illusions projected into the outside world?

[lady-ganesh.livejournal.com]

I had 'proper' hallucinations exactly once, when I was having a (very) bad reaction to medication. Interestingly, the hallucinations, rather than the extreme hyperactivity, were what sent my parents in a panic back to the doctor.

I've had auras for years; they used to come with more detailed hallucinations and now they just look kind of like an oil slick in my field of vision. I'm not sure if my young imagination/memory made the hallucinations more detailed or they were really like that.