Why having a poor sense of smell increases risk of depression



15:32 GMT, 22 March 2012

When standing on a hot, cramped train, you may have found yourself wishing you couldn't detect the whiffs of body odour emanating from your fellow passengers.

But a new study has suggested that the benefits of lacking this sense are few and far between.

Researchers from the University of Dresden found people born without a sense of smell felt more socially insecure and were at increased risk from depression.

You might prefer to not always have a sense of smell, but those born without it are at higher risk of having social insecurities

You might prefer to not always have a sense of smell, but those born without it are at higher risk of having social insecurities

While around one in five people have trouble with their sense of smell only one in 5,000 are born without it completely.

Rebecca Cagle, 52, from Tennessee, is one such sufferer and says she finds it difficult to relate to others without being able to share the experience of smell.

'People will ask me if I like the smell of their perfume or ask me if I
can smell something that they are smelling and I cannot relate to what
they are talking about,' Ms Cagle told ABC News.

The team questioned 32 adults with the condition – known as anosmia – about their daily lives, from social relationships to food preferences.

Writing in the open journal PLoS ONE, the scientists said subjects: 'reported worrying about their own body odour, having problems in interactions with other people and avoided eating with others.'

The participants said they found
interacting with colleagues or distant acquaintances most difficult – a
problem shared by Ms Cagle.

'I cannot
smell if I have bad breath or body odour,' she said.

'It can be offensive, to me and others around me.'

Coffee morning: Caffeine appears to trigger a protective reaction in the brain

Not smelling the coffee People with anosmia have reported feeling left out of sharing pleasant experiences

The researchers said: 'As olfactory cues (a sense of smell) are able to confer social information about others it is possible that patients have more problems in assessing others, because this channel of communication is closed.'

They added that this could be one reason why the patients had only half of the number of sexual relationships as a group of control participants.

However, the study found no significant
difference between the smelling and non-smelling groups in how many relationships they had had and how satisfied they were in them.

The patients with anosmia were also more likely to report having depressive symptoms. The team, led by Ilona Croy, said it wasn't known what was behind this link. However, they said other studies had suggested the two conditions might affect the same brain networks.