A pill to protect against stress? Jessica Hamzelou
IF YOU knew you were about to go through a stressful experience, would you pop a pill to protect yourself from its knock-on effects? It’s an idea that has been mooted after a drug seemed to make mice immune to the negative impacts of stressful events. But could we rationalise prescribing such a drug? We all experience stress during our lives, whether it be a one-off event, such as a loved one dying, or chronic, low-level stress that results from struggling to make ends meet, for example. While most people find ways to cope, for some a particularly stressful event can trigger depression. What if there was a way to boost our stress resilience and thus shield us from depression? Rebecca Brachman at Columbia University in New York stumbled across the idea while she was giving ketamine to mice with the symptoms of depression. Even though the ketamine14 | NewScientist | 30 May 2015
taking mice had been chronically stressed, when they were dropped in a pool of water – a one-off stressful event – they were unperturbed and swam to an exit. Mice not given the drug made no attempt to escape, a classic sign of depression in rodents. There was also no change in the ketamine-taking animals’ cognitive abilities or metabolism – both of which are altered in human depression. “It’s really remarkable,” says Brachman. “They basically look like mice that haven’t been stressed.” A single dose of ketamine protected mice from developing the symptoms of depression after stressful events for four weeks. But the drug only seemed to stop the symptoms of depression – some of the animals still exhibited anxiety behaviours. “It seems to protect against depression rather than anxiety,” says Brachman, who controversially describes it as a depression “vaccine”. The work will be published in Biological Psychiatry.
says. Stress is a normal part of most people’s lives, and can even be beneficial in some cases. Children who have dealt with stressful experiences tend to be better at dealing with stress later in life, says Figley. “The concern is that we’re medicalising normal behaviour.” Figley thinks that if a drug were available, it would be almost impossible to know who to give it to. Ian Anderson, a psychiatrist at the University of Manchester, UK, agrees. He points out that debates rage over whether to treat teenagers who show the vague behaviour changes that precede the delusions and hallucinations of schizophrenia. Many who have –Most people find ways to cope– these symptoms don’t develop schizophrenia, so doctors are If the findings translate to divided on whether they should humans, the idea that ketamine be treated with drugs. could protect us from depression “If you knew someone was after stressful events is very going into a very stressful exciting, says Gerard Sanacora situation, if you could find people at Yale University. who were vulnerable and protect The drug’s usefulness will them, that would be very useful,” depend on how long the effects says Anderson. “But you’d have to last, and how well you can predict be selective – you couldn’t just whether someone’s life is about give it to anyone willy-nilly.” to get really stressful, says Then there’s the use of Brachman. “It could be useful for ketamine – a well-known party soldiers, or people working in drug – itself. Ketamine has been natural disaster environments,” used as an anaesthetic since the she says. Sanacora adds that it 1960s, and has recently been might also be useful for people explored as an antidepressant. who have just been diagnosed Most existing drugs take weeks with a chronic illness. to act, whereas ketamine gives But not everyone is convinced. rapid results. It does, however, Military personnel currently have downsides: it can bring on receive psychological training hallucinations, and chronic use can damage the brain and bladder. “If you could find people Because the idea behind it as a who were vulnerable and way to build resilience to stress protect them, that would is to only take it sporadically, in be very useful” anticipation of stressful events, you would only experience the to boost their resilience, but all drug’s negative effects for a few approaches are experimental, hours, says Brachman. and none has been shown to be Ketamine is clinically approved particularly effective, says Charles as an anaesthetic so could be used Figley, a trauma psychologist at as soon as it is proven to work in Tulane University in New Orleans, people, she says. While Brachman Louisiana. plans to start testing this, she says And even if we could protect she will also look for other drugs someone from the effects of with similar effects but without stress, we might not want to, he the downsides. n