Gene link to optimism, self-esteem and depression

Gene link to optimism, self-esteem and depression

By Liz Lockhart

Whilst genes play a role in our understanding of psychological disorders they are only part of the picture. Factors such as childhood experience, good relationships and even the effect of other genes all play an equal role.

University of California Los Angeles (UCLA) scientists have identified a particular gene’s link to optimism, self-esteem and mastery (the belief that one has control over one’s own life).  These are three critical psychological resources for coping with stress and depression.

The senior author of this new research, Shelley E. Taylor, a distinguished professor of psychology at UCLA said ‘I have been looking for this gene for a few years and it is not the gene I expected.  I knew there had to be a gene for these psychological resources.’

The gene Taylor and colleagues identified is the oxytocin receptor gene (OXTR).  Oxytocin is a hormone that increases in response to stress and is associated with good social skills such as empathy and enjoying the company of others.

‘This study is, to the best of our knowledge, the first to report a gene associated with psychological resources,’ said Shimon Saphire-Bernstein, lead study author.  ‘However, we wanted to go further and see if psychological resources explain why the OXTR gene is tied to depressive symptoms.  We found that the effect of OXTR on depressive symptoms was fully explained by psychological resources.’

At a specific location the oxytocin receptor gene has two versions: an ‘A’ (adenine) variant and a ‘G’ (guanine) variant.  Other studies have suggested that people with at least one ‘A’ variant have an increased sensitivity to stress, poorer social skills and worse mental health outcomes.

In this study researchers found that people with either two ‘A’ nucleotides or one ‘A’ and one ‘G’ at this particular location on the oxytocin receptor gene have substantially lower levels of optimism, self-esteem and mastery.  They also have significantly higher levels of depressive symptoms than people with two ‘G’ nucleotides.

The findings are ‘very strong and highly significant’ said Taylor. This study could have important implications.  ‘Sometimes people are sceptical that genes predict any kind of behaviour or psychological state.  I think we show conclusively that they do,’ said Taylor.  However, Taylor stresses that while genes may predict behaviour, they do not determine it. 

‘Some people think genes are destiny, that if you have a specific gene, then you will have a particular outcome.  That is definitely not the case,’ Taylor said.  ‘This gene is one factor that influences psychological resources and depression, but there is plenty of room for environmental factors as well.  A supportive childhood, good relationships friends and even other genes also play a role in the development of psychological resources, and these factors also play a very substantial role in whether people become depressed.’

‘There is a genetic basis for these resources, but no – the OXTR gene does not explain most of these resources.  The more you study genes, the more you realise that many factors influence their expression.’

‘The expression of genes is not always stable,’ Saphire-Bernstein noted.  ‘For physical features like eye colour, it is stable.  Your eye colour is not going to change this week, but our depression might change this week.  Genes are only one set of contributing factors to behaviour, to illness and to psychological disorders such as depression.’

For the research 326 people were brought into a UCLA laboratory and researchers had them complete self-assessments of optimism, self-esteem and mastery.  Questions were designed to target each of these three specifics.  The researchers then obtained DNA from the participants’ saliva which was analysed for the variants in the OXTR gene.  Participants also completed an assessment of depression.

‘People with the ‘A’ variant scored substantially higher on depression.  The question is whether that association between the gene and depression is explained by psychological resources,’ said Taylor.  ‘We found the answer is yes.  The reaction of the gene to depression is explained entirely by these psychological resources.  Taylor was honoured last year with the American psychological Associations Lifetime Achievement Award.

The research implies that people would benefit if they could train themselves to be more optimistic, to have higher self esteem and a higher sense of mastery to improve their ability to cope with stressful events.

Taylor said ‘The benefits that tending provides to children, especially those with genetic risks, are substantial. From life in the womb to the surprisingly resilient brain of old age, the social environment molds and shapes the expression of our genetic heritage until the genetic contribution is sometimes barely evident. A mother's tending can completely eliminate the potential effects of a gene; a risk for a disease can fail to materialise with nurturing, and a genetic propensity may lead to one outcome for one person and the opposite for another, based on the tending they received.’

The research is currently available in the online edition of the journal Proceedings of the National Academy of Sciences and will appear in a forthcoming print edition. 

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