Over six percent of us experience "phantom odor perception"

About 7 or 8 years ago, I started experiences episodes of smelling a burning paper odor, even though there wasn't any source for the odor. It would last for a few days, then abruptly stop, and return a few weeks later. I started tracking these episodes, and found that they are very loosely correlated with lack of sleep and stress. Sometimes the weird smell starts while I'm feeling great, though, so I really didn't know what the cause was. I asked Oliver Sacks about it when I was interviewing him about his book Hallucinations, and said he had no idea why I smelled things that weren't there.

Today, Gizmodo linked to a newly published paper from the the National Health and Nutrition Examination Survey called "Factors Associated With Phantom Odor Perception Among US Adults" and it describes my experience perfectly -- an "unpleasant, bad, or burning odor when no actual odor exists."

The study found that phantom odor perception was more prevalent among "among women, younger age groups, and those of lower socioeconomic position," and was "more common among those with poorer health, a history of head injury, or dry mouth symptoms."

Head injuries as a possible cause might explain why I experience this. When I was 13 or 14 I was skateboarding down a steep hill in Boulder Colorado without a helmet (Columbine street, for those who know it). I don't remember falling off the board. I woke up in the ambulance with a broken nose, a torn chin, and knocked out teeth. Read the rest

Guy gets super-high on ayahuasca, gets cosmic woodworking instructions

Chris Isner was a regular guy until an ayahuasca trip gave him clear instructions on creating a trippy style of bas relief wood sculptures. Read the rest

Psychological disorder causes you to hallucinate your doppelgänger

In the book The Man Who Wasn't There, Anil Ananthaswamy explores mysteries of self, including the weirdness of autoscopic phenomena, a kind of hallucination in which you are convinced that you are having an out-of-body experience or face to face with your non-existent twin. Read the rest

Watch a short survey of subconscious cinema

Nightmares, hallucinations, daydreams, memories, and fantasies get mashed up in Dreamscience's well-crafted survey of dream sequences in film. NOTE: contains some disturbing images, like the eyeball scene in Un Chien Andalou. Read the rest

VIDEO: Hallucinatory NARCOSE captures free diving's beauty and danger (NSFW)

Thalassophobes and NSFW-phobes will want to skip this beautiful short about deepwater free diver Guillaume Néry and the kinds of hypoxia-induced hallucinations he experiences when free diving to depths beyond 100 meters. Thalassophiles who love beautiful underwater cinematography and trippy dream sequences will find the underwater footage hypnotic. Read the rest

Caffeine hallucinations: Why "Letters to the Editor" matter in science

Letters to the Editor are an interesting feature of peer-reviewed scientific journals. The function of this section varies from journal to journal, but, in general, this is where you'll find things like critiques of research published in previous issues, and short write-ups on findings that don't yet warrant their own big, formal research paper. Neuroscience blogger Vaughan Bell found a neat example of the latter in an old 1993 issue of the American Journal of Psychiatry.

Dr. Harold W. Koenigsberg and his colleagues were in the process of studying the causes of panic and anxiety disorders, in hopes of better understanding why some people are prone to panic attacks and others aren't. Part of that research involved determining whether you could have a panic attack while sleeping. They wanted to see whether a panic attack could still happen if the patient wasn't actively thinking about the causes of the panic attack, like they might when awake. Basically, Koenigsberg was trying to figure out how much of a panic attack was attributable to chemistry changes, and how much was related to cognitive processing.

Koenigsberg and company injected sleeping patients with caffeine, to produce the physical symptoms of panic. And that's when they noticed something odd. Two of the patients reported olfactory hallucinations—they smelled things that weren't there. Here's what Koenigsberg wrote in his Letter to the Editor:

Mr. A, a 38-year-old man with no personal or family history of psychiatric disorders, received an intravenous dose of 250 mg of caffeine, delivered as a bolus over a 60-second period during an episode of stage 3-4 sleep.

Read the rest