Editors note: Psilocybin mushrooms are classified by the federal Drug Enforcement Agency as a Schedule I substance, which it defines as having no currently accepted medical use and a high potential for abuse. This category includes marijuana and heroin. Penalties for possession and sale of psilocybin vary by state, as this essay demonstrates. Readers who are experiencing substance abuse issues in the U.S. can call 800-662-HELP (4357) for the SAMHSA National Helpline.

Neurologists say its some of the worst pain known to medical science right up there with kidney stones, childbirth and amputation without anesthesia. Its so bad that as many as 25% of sufferers report suicidal intentions during the course of their ailment.

Cluster headaches.

I was 33 and living in Portland, Oregon, when I first started getting them. They came like clockwork every night at 1, dragging me out of my dreams and onto my feet. The pain was unbearable like a dental pick raking the inside of my skull. Tears streamed from my left eye, my eyelid sagged, my nostril clogged.

Invariably I found myself on the floor, clawing carpet tendrils, sucking air through clenched teeth. Noises I didnt recognize as my own came gurgling out my throat, as if by their own accord. Sometimes during a particularly bad episode, I was reduced to sobbing. I wished for any kind of relief, even death.

But there was no escape. For an hour or sometimes more, there was only the pain. And after the pain, the terror of anticipating the next attack.

Always, the terror of the next one.

Online, I quickly self-diagnosed. I learned that attacks occur in metronomic precision, with cluster cycles lasting seven days to one year, separated by remissions of one month or longer. I learned that irregularities within the hypothalamus, the brain region responsible for circadian rhythms, are thought to play a role in the diseases pathology . I also learned that high-flow oxygen can abort attacks. I didnt have health insurance, so I searched frantically for an alternative remedy. Friends recommended cayenne pepper, hot steam, ibuprofen. Only ice helped sort of.

Nestled at the bottom of the Wikipedia page on cluster headaches were a few sentences on psychedelic therapy: Some controversial case reports suggest that ingesting LSD, psilocybin [a hallucinogenic compound found in some mushrooms], or DMT can reduce pain and interrupt cluster headache cycles. According to a survey of 53 cluster headache sufferers conducted at Harvard McClean Hospital, 22 of 26 psilocybin users reported aborted attacks; 25 of 48 reported cluster cycle termination. Eighteen of 19 psilocybin users and 4 of 5 LSD users reported extended remission. To abort an attack, a sufferer only needs a small amount a tenth a hit of LSD, or one medium-size mushroom.

I was skeptical. Id done shrooms in my 20s. They made me feel like Id been poisoned. I was nauseous, manic, vertiginous, and torpid often all at once. How would psychedelics do anything other than exacerbate an already hellish situation?

The only way to find out, I told myself, picking up the phone and calling one of my shroom-loving friends, was to try.

The next morning while doing laundry, I was struck by a momentary sensation like the beginning of an attack. Because the headaches had been coming only at night, I wrote it off as paranoia. But the sensation persisted, and was soon accompanied by a sagging eyelid and clogged nostril. A daytime cluster headache: my first.

Remembering the mushrooms I had bought the night before, I hurried to the kitchen. They resembled small, gnarled pieces of driftwood bone-white with bluish splotching and not something youd want to put inside you. For several long minutes I stared at the bag. Maybe the Harvard McLean study was bogus. Maybe theyd make me sick.

I fished out a half-inch stem and chewed it quickly, washing down the bitter taste with water. If there was any consolation, the recommended dosage was small; side effects should be small, too subtle visual distortions, mild anxiety, heightened awareness. Some cluster headache sufferers who shared their experiences on webboards likened the side effects to a strong beer buzz. Others claimed significant psychedelic experiences. The truth was, I didnt know what to expect. I only knew one thing: the pain was so bad I wouldve tried almost anything to stop it.

I got an ice pack, went to the bathroom, and closed the blinds. It wasnt long before I was on the floor, rocking back and forth, mashing the ice against my throbbing eye. No stimuli was unhurtful: A distant passing truck; the dripping faucet; my neighbors radio like knife strokes, all of them.

A wash of warmth flooded my gut. The mushrooms. Almost immediately the pressure behind my eye began to subside. My clogged nostril loosened. The tearing stopped.

The pain was gone; the attack, aborted.

Dumbstruck laughter bubbled out of me. I tossed the ice in the freezer and went outside. It was a beautiful day, three tiers of clouds layering the sky. The mushrooms hadnt made me feel poisoned or sick. The effect was mild, like caffeine, only cleaner. I wasnt tripping just pleasantly buzzed. Brighter colors, sharper sounds, and an overall sense of well-being. So complete was the relief it seemed mushrooms actually were cluster headaches antidote. It was almost as though the disease were the result of a psilocybin deficiency. I wanted to stop traffic and shout magic mushrooms cure cluster headaches! at the top of my lungs.

From then on, I was never without a small stash. I brought them with me to work, on social outings, and camping trips. Cluster headaches are like storms: you can sometimes see them coming, sometimes not. Without mushrooms, I wouldve been afraid to leave home. Every time I felt an attack coming on, Id take a small stem and cap, and 20 minutes later, Id be good as new.

Mushrooms even gave me the confidence to attempt a cross-country bike tour. In the summer of 2011, I sold my stuff, quit my job and left Portland for Walden, Colorado, a small town in the northern Rockies where my brother lived. After spending the winter there, I planned to resume the trip in the spring, with any luck making it to my hometown Lansdale, Pennsylvania before the following summer.

I made it across the Cascades, through eastern Oregons deserts, and over Idahos mountainous interior without an attack. But then one afternoon in Wyoming, I felt a twinge behind my eye. I all but dumped my panniers on the highway in search of my mushroom stash. What was I thinking, making this trip? Here I was, on the side of a desert road, 15 miles from the nearest town, the air like a kiln. Luckily, the pain remained a dull throb what we cluster headache sufferers call shadows. And 20 minutes later, after the mushrooms worked their magic, I was on my bike.