People who suffer severe depression find it more difficult to tell one facial expression from another, according to research from the University of Otago, Christchurch. This reduced ability to interpret expressions was particularly notable with expressions of disgust, the first time this has been reported. In the study, 68 people with severe depression and 50 healthy individuals were shown in total 96 faces displaying five basic emotions – angry, happy, sad, fearful and disgusted – as well as neutral expressions. Researchers Professor Richard Porter and PhD student Katie Douglas found the “healthy group” was significantly better than the “depression group” at recognising facial expressions of disgust, indicating an impaired ability of people with severe depression to recognise this facial expression. The study also found “neutral faces” were more likely interpreted as sad by those with depression, and less likely as happy - findings consistent with previous studies. Professor Porter, of the Department of Psychological Medicine, says a poorer ability to recognise expressions of disgust is also seen in Parkinson's disease patients with low levels of the brain chemical dopamine, and it is possible dopamine dysfunction operates in people with severe depression as well. Another explanation is that people's emotional processing is affected when they are severely depressed and in stressful situations. The study is published in the August 2010 issue of the British Journal of Psychiatry.