A VACCINE FOR STRESS?

Scientists have long observed that physical and mental problems caused by stress have a strong association with immune system changes. This has given rise to a new wave of research, looking at whether modifying the immune system through vaccines might make us more resilient to stress. Neuroscientists at Columbia University, US, have transferred immune cells from chronically stressed mice to unstressed mice, and found that the unstressed mice became more resilient to stress, showing fewer depressive symptoms. Separately, neuroscientists from the University of Colorado have modulated the immune system of mice by injecting them with species of bacteria known to decrease anxiety. When these mice were placed in a cage with aggressive animals, they were less intimidated than unimmunised mice, and later displayed none of the stressrelated gut problems that the unimmunised mice had. Could this mean an anti-stress vaccine is a possibility? Christopher Lowry, lead researcher at Colorado, has announced he is pushing forward with human trials. Ultimately, he believes the bacteria – given by pill, inhalation or injection – could help people buffer the physical and behavioural side effects of stress. Soldiers at risk of PTSD are the most obvious candidates for the bacterial stress vaccine, says Lowry. But who knows what next? A pre-exam vaccine for pressurised teenagers?