One early morning in June, Kevin L. Ellis, 45, climbed inside a stranger’s car and refused to get out. Police officers arrived and pulled him through the door to the ground, then shocked him with a Taser at close range. At some point, he stopped struggling. An ambulance took him to a hospital where he was pronounced dead.

There was no heart attack, no respiratory failure, no organ meltdown; no obvious reason why Ellis had stopped living. Last week, a local medical examiner ruled that the death was due to methamphetamine intoxication complicated not by the electrical shock from the Taser, but by "excited delirium," a controversial diagnosis that some say can cause death. Fatal excited delirium is often recorded simultaneously with methamphetamine, cocaine, and other psychostimulants. It also frequently occurs in cases where the victim expired soon after being hit with a Taser.

Keith Graff, 24, died in Phoenix, Arizona in 2005 after being tased for 84 uninterrupted seconds. The official cause was "excited delirium due to methamphetamine intoxication." Robert Knipstrom, 36, died from "acute ecstasy intoxication and excited delirium" after being tased multiple times in Canada. Xavia Jones, an ex-con in Miami, was tased repeatedly and used his final breath to cuss out police before he died, officially, of "excited delirium syndrome, associated with cocaine use." In 2010, in Middletown, Connecticut, 35-year-old Efrain Carrion died from "excited delirium" and nothing more, after police tased him and chased him into the woods behind his house.

Excited delirium sounds like one of those dubious, catch-all diagnoses, like "hysteria," "sudden in-custody death syndrome," or the more accepted and less controversial "sudden infant death syndrome." But the American College of Emergency Physicians (ACEP), a trade association that represents more than 30,000 emergency medical workers, says excited delirium is a distinct medical condition that can cause sudden death.

Excited delirium is like a bad bath salts trip

"Excited delirium is a very real condition and very much exists," says Dr. Howard Mell, a spokesperson for ACEP who has seen patients experiencing excited delirium. Symptoms are not unlike a bad bath salts trip. Victims are usually agitated, belligerent, and incoherent. They have elevated body temperatures as high as 108 degrees Fahrenheit, and superhuman strength. Often, they disrobe.

"Your heart rate goes up uncontrollably, your temperature goes up uncontrollably," Dr. Mell says. "The equivalent would be taking a car and putting the gas pedal all the way to the floor and just leaving it there and eventually the engine revving so fast that it blows apart." This can affect heart, lung, and kidney function, and cause the blood to become acidic, he says.

Others aren’t so sure. "It’s usually an exclusionary diagnosis. If you can’t find anything else, then you say that," Dr. Howard Zonana, a psychiatrist at Yale University, told the Burlington Free Press. Civil rights advocates say the diagnosis is being used to "whitewash clear cases of police abuse," as Eric Balaban of the American Civil Liberties Union told NPR in 2007. A police psychologist in Canada blasted Taser International for having "brainwashed" police into using Tasers to treat the "mythical" condition. Either way, awareness of excited delirium has risen since being linked to deaths that occurred in police custody, often after the use of a Taser.

Taser acknowledges that there may be some relationship between Taser usage and death from excited delirium in the release agreement that officers must sign before taking the company’s optional training course. "Some individuals may be particularly susceptible to the effects of [conducted electrical weapon] use," the document says. "These susceptible individuals include the elderly, those with heart conditions, asthma or other pulmonary conditions, and people suffering from excited delirium ... In a physiologically or metabolically compromised person, any physiologic or metabolic change may cause or contribute to sudden death."

Critics say excited delirium, in which the exact means of death is undetermined, is merely a euphemism for "death by Taser." While a diagnosis of excited delirium is extremely rare, it frequently occurs in tandem with tasing. "Excited delirium" was a cause of death in 111 cases in which a victim had first been tased, according to Amnesty International.

Critics say excited delirium is merely a euphemism for "death by Taser"

Death after tasing is also rare. According to Taser International, the weapon has been deployed 1.9 million times in the field and 1.3 million times in training and voluntary applications since it was introduced in 1994. According to Amnesty International, there have been 552 cases since 2001 in which a Taser was used on a victim who then died. Medical examiners explicitly cited tasing as a cause or contributing cause of death in only 60 of those cases.

Even though Taser’s training materials warn that victims experiencing excited delirium may be at greater risk of death from tasing, the company disputes any connection between its product and death from excited delirium. "These deaths have been occurring well before our company started," says spokesperson Steve Tuttle. "In-custody deaths are not anything new."

Most Taser-related deaths are caused when police stun a suspect who is in a dangerous position, causing the victim to fall to his or her death, Tuttle says. He also pointed to Taser’s estimate that the device has saved more than 113,000 lives because it’s used in place of more lethal measures.

Taser has also been doing its part to spread awareness of excited delirium, which Tuttle says will lead to more police awareness and fewer in-custody deaths. The Institute for the Prevention of In-Custody Deaths, which does workshops on how to recognize excited delirium patients, has close ties with Taser, according to Mother Jones.

The excited delirium diagnosis has long been the subject of skepticism. In 1999, the ACLU and other advocates argued that deaths attributed to excited delirium were really due to pepper spray. Versions of the syndrome date back to 1849, but the diagnosis caught on in the mid-80s at the beginning of the crack cocaine epidemic. The syndrome has also been blamed in a handful of deaths that occurred outside of custody, including Major League baseball player Darrell Porter.

Dr. Deborah Mash, a neurologist at the University of Miami, has been studying excited delirium for more than 20 years and posts her research on exciteddelirium.org. She believes there may be a gene that predisposes people to experience excited delirium, in addition to factors such as extreme stress and alcohol withdrawal. (Another researcher, Dr. William P. Bozeman, has a theory that death is caused by a pre-existing cardiac condition called Long QT Syndrome.)

"Excited delirium deaths occurred before there were TASERs."

Excited delirium doesn’t manifest as an anatomic cause of death, Dr. Mash says, which makes it ripe for wrongful death lawsuits. The people who deny that excited delirium is a real medical condition are often in litigation with the police or Taser, she says.

"I never got calls about this until the Taser was implemented. Then all of a sudden it became a very serious situation from a medical, legal standpoint," she says. "There is no connection between Tasers and excited delirium deaths. Excited delirium deaths occurred before there were Tasers."

There’s still debate around whether excited delirium is a medical condition, and if so, whether its presence in combination with tasing can cause death. It’s unclear whether the basic facts are even trustworthy. According to Mother Jones, one survey showed that 35 percent of medical examiners were so afraid of being sued by Taser that their conclusions after an autopsy would be skewed. Taser International has made every effort to dispel the notion that its nonlethal weapons kill. But without a clearer explanation of how excited delirium causes death, the stun guns will continue to be suspect.