A recent study showed that hostile people were more likely to have a stroke – although the results are not as clearcut as they first seem.

Are you a type A personality? Someone who is often hostile, aggressive, impatient and with a quick temper? Then you might have read with alarm some recent headlines claiming that such behavioural traits dramatically increase your risk of stroke.

Researchers from the Hospital Clinico Universitario San Carlos in Madrid, Spain analysed data from 150 people with an average age of 54, all of whom had been admitted to a stroke unit, and from another group of 300 randomly selected people who were healthy, from the locality.

The study participants had their levels of chronic stress assessed using various checks – major and stress-inducing life events, symptoms such as anxiety and depression; overall wellbeing; and behaviours that indicate a type A personality. All participants were also checked for other risk factors relating to stroke such as diabetes, high blood pressure and cholesterol levels, for example.

Stroke

Those of the stroke group who’d experienced a major life event were four times more likely to have had a stroke in the previous year. And a high score for being a type A personality more than doubled the risk of stroke. This difference was true even when other risk factors such as unhealthy lifestyle were taken into account.

However, the results of this study aren’t as clearcut as they may at first seem. The main problem with it is that the stroke patients were asked about stressors in their lives after they had suffered a stroke. In hindsight, we often infer meaning to events where they may have been none.

The healthy people who were questionned may have been just as stressed but because they hadn’t suffered a stroke, weren’t so acutely aware of it. This is what researchers call ‘recall bias.’ A good number (about 40%) of the original pool of stroke sufferers had to be excluded from the study because they were unable to speak clearly enough to participate. Because of this the group of study participants was very small and also of a very localised group of people, so can’t be seen as representative of the population at large. So this study doesn’t prove that stress causes stroke or even raises your risk of it.