Source: Time Magazine

During a recent therapy session, one of Dr. Norman Rosenthal’s regulars said he was considering suicide. It wasn’t the first time the patient had entertained the thought, and even though he was on antidepressants and always kept up with his appointments, Rosenthal, a licensed psychiatrist with a private practice in North Bethesda, Md., wanted to offer his patient something else.

“I think you should get Botox,” Rosenthal told him. “You should schedule an appointment on your way home.”

It was peculiar advice coming from a shrink, but not without precedent. In 2014, Rosenthal, a clinical professor of psychiatry at Georgetown University School of Medicine, and Dr. Eric Finzi, an assistant professor of psychiatry at George Washington School of Medicine, published a study showing that when people with major depression got Botox, they reported fewer symptoms six weeks later than people who had been given placebo injections. “I’m always on the lookout for things that are unusual and interesting for depression,” says Rosenthal, who is widely considered an expert on the condition. “I’ve found Botox to be helpful, but it’s still not mainstream.”

It’s also not approved by the U.S. Food and Drug Administration (FDA) for depression, not that that stops doctors from prescribing it that way. Such off-label use of Botox, like that of any FDA-approved drug, is legal in the U.S. That’s because once a drug has been approved by the FDA for a condition, licensed physicians are legally allowed to prescribe it for any medical issue they think it could benefit, regardless of whether it’s been proved to work for that condition.

Now, thanks in large part to off-label use, Botox–the wrinkle smoother that exploded as a cultural phenomenon and medical triumph–is increasingly being drafted for problems that go far beyond the cosmetic. The depression suffered by Rosenthal’s patient is just one example on a list that includes everything from excessive sweating and neck spasms to leaky bladders, premature ejaculation, migraines, cold hands and even the dangerous cardiac condition of atrial fibrillation after heart surgery, among others. The range of conditions for which doctors are now using Botox is dizzying, reflecting the drug’s unique characteristics as much as the drug industry’s unique strategies for creating a blockbuster.

Botox is a neurotoxin derived from the bacterium Clostridium botulinum. Ingested in contaminated food, it can interfere with key muscles in the body, causing paralysis and even death. But when injected in tiny doses into targeted areas, it can block signals between nerves and muscles, causing the muscles to relax. That’s how it smooths wrinkles: when you immobilize the muscles that surround fine lines, those lines are less likely to move–making them less noticeable. It’s also why it’s FDA-approved to treat an overactive bladder: Botox can prevent involuntary muscle contractions that can cause people to feel like they have to pee even when they don’t.

In 2015, Botox, produced by pharmaceutical maker Allergan, generated global revenue of $2.45 billion–more than half of which came from therapeutic rather than cosmetic uses. That noncosmetic revenue is likely to balloon in the years ahead as doctors try out Botox for even more off-label uses and as Allergan conducts studies of its own.