Chronic sleep deprivation – or a severe, short-term lack of Z’s from, say, cramming for exams over two straight nights – can make you silly or sad, slow to react, memory-impaired and more apt to take risks.

But what it rarely does, according to a leading sleep expert, is make you go temporarily insane, as a JetBlue Airways pilot apparently did on a March 27 flight from New York to Las Vegas. After Clayton Osbon had a cockpit meltdown, ranting about religion and terrorists, passengers eventually wrestled him to the cabin floor and a co-pilot safely landed the plane. Osbon was charged with interfering with flight crew instructions.   

During the pilot's trial, a psychologist testified that Osbon suffered "a brief psychotic disorder" due to lack of sleep, according to a court transcript obtained by The Associated Press on Tuesday. A federal judge in Texas agreed with that notion and on July 3 ruled Osbon not guilty by reason of temporary insanity.

“But if somebody is going to have a psychotic episode due to sleep deprivation, it’s usually not the first time it’s going to happen, and usually there is a history of depression or other psychiatric illness," said Michael J. Breus, Ph.D., a Scottsdale, Ariz.-based clinical psychologist and a member of the American Board of Sleep Medicine.

Breus has not reviewed Osbon’s case and can only speak, he said, from his experiences with other patients and from existing literature.

“I don’t know about this pilot’s mental health background. But think back to when you were in college. Did you ever pull an all-nighter? I sure did. Last time I checked, people who pull all-nighters don’t go screaming through the hallways screaming bloody murder at the top of their lungs,” Breus said.

At Osbon’s trial, forensic neuropsychologist Robert E.H. Johnson testified that Osbon's disorder lasted roughly one week after his mental break aboard the flight. On the stand, Johnson did not make clear how long Osbon went without sleep. The pilot’s psychiatric evaluation was sealed during the trial, according to the AP. A JetBlue spokeswoman told the AP that Osbon did not fly March 24 or March 25, and worked a round-trip flight March 26, meaning he had 17 hours of down time before his March 27 departure to Las Vegas.

“The deprivation that would probably be required for somebody to have a psychotic episode - if they’ve never had one before - he’s going to had to have been up for a couple of days,” Breus said.

More commonly, especially among emergency room doctors and the parents of newborns, acute sleep deprivation (one or two nights without any sleep) or partial, chronic sleep deprivation (maybe four hours per night over several weeks) can trigger an array of less-frightening symptoms, Breus said.

Depending on how much sleep they are lacking and how long they’ve gone without closing their eyes, people can hallucinate and find things funny that aren’t the least bit comical – also known as being giddy, Breus said.

“Also, your reaction time slows down: you may drive like you might be drunk,” Breus said. “You’re not making decisions the way you should. Data also shows that people take higher risks when sleep deprived.”

He cited cases of gamblers, wagering without much sleep, who disregard high odds and plunk down tall stacks of chips anyway. 

“They knew the risks or odds at the table but they didn’t care,” Breus said.

Inappropriate emotional swings also can take root, meaning people laugh more hysterically than they should when watching marginally funny events, or they become more depressed than is necessary when they witness something just a bit sad.

Oddly, in people diagnosed with depression, their mood can actually lighten when they go 24 hours without sleep – and their depression returns after rest, Breus said.

“What happens with sleep deprivation is usually not permanent. It’s usually temporary,” Breus said. “So you’re sleep deprived, you have some weird behaviors, you react slowly, your mood changes. But once you get some sleep, that stuff goes all away. How long has that pilot been in the hospital now?”

Osbon remains at a mental health facility in Fort Worth, the AP reported. He is scheduled for a hearing early next month during which his possible release from that hospital will be examined. 

Related: 

• Some insomniacs may just be afraid of the dark
• Why do we twitch as we're falling asleep?
• Waking a sleepwalker is totally safe -- for them

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