A couple of years ago, some researchers at Keele University in England published a study purporting to show that swearing relieved pain. It was a small study (just 67 participants) and the explanation—that swearing perhaps triggers a fight-or-flight response from the amygdala that suppresses awareness of pain—is completely speculative.
But even if that study is right, some new research may have uncovered a flaw in the "Swear and Feel Better" plan. Swearing may deaden physical pain, but it could also deter other people from offering you emotional support. At the very least, swearing in front of other people is associated with feeling like they aren't offering you as much emotional support.
Megan Robbins and her team recorded snippets of speech from middle-aged women with rheumatoid arthritis, and others with breast cancer, and found those who swore more in the company of other people also experienced increased depression and a perceived loss of social support.
The sample sizes were small (13 women with rheumatoid arthritis and 21 women with breast cancer), but the technology was neat. The women wore "an electronically activated recorder" that periodically sampled ambient sounds, including speech. A lapel microphone recorded 50s every 18 minutes over two weekends for the arthritis sample and 50s every 9 minutes over one weekend for the breast cancer patients. Two months or four months after baseline the women repeated measures of their depression and perceived social support - the latter measured by agreement with statements like "I get sympathy and understanding from someone". The key finding is that higher rates of swearing in someone else's company, but not solitary swearing, were associated with an increase in depression symptoms and a drop in perceived social support. Moreover, statistical analysis suggested the effect of swearing on depression was mediated by the lost social support.
Of course, there could also be some socio/cultural factors at work here, too. All the participants in this study were middle-aged women. Would middle-aged men—or, for that matter, women of a younger, more-swearing-prone generation—feel the same way? There's a possibility that this study could have more to say about what middle-aged women expect from themselves, or who other people expect them to be.