Ground down

FRIEDRICH NIETZSCHE’S widely cited maxim—“that which does not kill him makes him stronger”—is often taken as truth. Yet as sensible as it might seem, the saying has rarely been tested. Psychologists have little idea whether unpleasant experiences really do increase resilience. A study just published in Psychological Science suggests they do exactly the opposite.

In 1995 David Almeida, a psychologist at Pennsylvania State University, began an experiment involving 1,483 people. He asked them to take two tests. The first involved reporting, on a scale of one to five (where one was “none of the time” and five was “all of the time”), how often during the previous 30 days they had felt worthless, hopeless, nervous, restless or fidgety; how much of the time everything felt like an effort; and how often they were so sad that they felt nothing could cheer them up.

The second test asked whether any of several types of stress had happened during the course of the previous day. These stresses included arguments; situations in which participants felt they could have argued but chose not to; problems at work; problems at home; and feeling upset over a problem that a friend was struggling with. Finally, participants were asked whether they had been treated for anxiety, depression or any other emotional disorder during the previous year.

Dr Almeida then let a decade go by, after which he attempted to recontact the participants. Some had died, some refused to take part a second time, and some had moved. That left 711 people. He once again asked them to report, using the same scale, how often they had felt the various negative feelings during the previous 30 days. He also asked again whether they had been given treatment for emotional disorders during the previous 12 months.

When he and his colleagues analysed the answers, they realised that, contrary to Nietzsche’s dictum, seemingly trivial daily stresses in the past had taken a long-term toll on mental health. They found that the more often people (who had not then been treated for a disorder) felt nervous, fidgety, worthless or hopeless ten years ago, the higher were their chances of having developed a disorder in the interim.

It may, of course, be that this reflects someone’s underlying personality, rather than the actual slings and arrows of outrageous fortune. Different people will react differently to events. What makes one person feel worthless may be shrugged off by another. But the study does suggest that for some, even minor setbacks can be malevolent—weakening the psyche, rather than strengthening it, as Nietzsche suggested they should.