When Eric Haller gets sick and goes into an "episode" -- about eight to 10 times a year -- he slips into a dreamlike state and is unable to do simple cognitive tasks, like reading, adding up numbers or comprehending his favorite TV shows.
The 21-year-old from Placentia, Calif., has a 3.5 average at Fullerton State University and interns for the L.A. Clippers, but his capabilities disappear when he descends into a trance.
Haller has Kleine-Levin syndrome, a rare sleep disorder that is characterized by recurring but reversible periods of excessive sleep, sometimes up to 20 hours per day, accompanied by childlike behavior.
Just last week, he came out of an episode that lasted 30 days. The one before that was 37 days.
"When I go through it, it's complete hell for me," said Haller. "It doesn't feel real and it's hard to understand what people are saying. It's so frustrating, because I want to understand."
Symptoms include excessive food intake, especially "junk food," plus "irritability, childishness, disorientation and hallucinations," according to the National Institute of Neurological Disorders and Stroke.
More than 70 percent of those who have KLS are male, and it affects only about 1,000 children and young adults worldwide.
Doctors know little about the disorder but suspect it may be related to a malfunction of the hypothalamus and thalamus, parts of the brain that control appetite, sleep and sexuality.
The disease is typically diagnosed around age 11, and episodes eventually decrease in frequency and intensity over the course of eight to 12 years.
The hardest part is psychological for both KLS patients and their caregivers, who report feeling the stress of this capricious condition.
Sometimes, patients babble like babies, barely incomprehensible -- and others can act out sexually.
Haller is an avid sports fan, but he could barely remember the Super Bowl, which had taken place during his last trancelike episode. It was just too taxing for him to follow.
Often these children are sent for psychiatric evaluation or misdiagnosed with mood or behavior problems. It took doctors four years to diagnose Haller with KLS.
In between episodes, those affected are perfectly normal, and the memories of how they behaved are "hazy," according to Haller.
"Normally, Eric is a loud mouth, a sport-loving guy," said his mother, Lori Haller-Schiller. "I never know when it will come on. It's like a light switch and he turns into a child. He likes sleeping and is very crabby and doesn't like to talk."
He also gets fast-food cravings, according to Haller-Schiller, who is on the board of the KLS Foundation.
"Every day I go to Chick-fil-A and order a meal for three people. It's so weird, and the Gummy Worms.… He doesn't eat like that normally."
She said he will watch Seinfeld reruns for hours and resort to childhood cartoons. He misses about 100 days of reality a year, she said.
After coming out of the last episode, he was surprised to learn that Jeremy Lin had become world-famous, even though he works for a professional basketball team. Haller remembered he had seen him on the cover of Sports Illustrated, but thought, "What the heck is this?"
"I don't really know when it's coming on -- I get two or three days' warning, maybe," he said. "I wake up and feel a little off – not aware and everything seems dreamlike. I can function but it keeps getting worse, day by day."
His first episode happened at about age 11. "I was crying because I couldn't do basic math homework, and I was a very smart kid."
Haller-Schiller said it took two years to diagnose her son. His parents took him to a psychiatrist thinking he was depressed and then to a sleep specialist, but they could find nothing wrong. Eventually, doctors solved the mystery.
"The worst part is not knowing. But when we got to the remarkable stage when we could talk to someone for the first time, it was amazing," said Haller-Schiller. "It was bittersweet."
In public school, Haller was given an individualized education plan because the episodes disrupted his ability to do homework. He also cannot be left alone during these periods, according to his mother.
Haller and his family draw inspiration from AAlanna Wong of Seattle, who also has KLS.
Britain's Daily Mail newspaper described how the 22-year-old was first misdiagnosed with schizophrenia. One of her episodes lasted eight months.
Now, Wong writes a blog, My KLS Life, with stories and coping tips to help others.