How much are moods and attitudes influenced by upbringing and experiences, the classic ‘nurture’ half of the ‘Nature/Nurture” dichotomy and the basis of theories of inter-personal psychology and “Personal Growth”?

Could it be that they are  also  influenced by a genetic disposition to optimism or pessimism?

First we should look at how this could occur. It is easy to think of ‘moods’ as if they are just imprecise non-physical ‘feelings’ or ‘emotions’ but of course we know that they are accompanied by or caused by chemical changes in the brain.

An example is that vigorous exercise produces endorphins, the body’s own painkillers and mood-enhancers. The endorphins change the brain’s chemistry and change mood. Going to the Gym really can cheer you up, it’s a chemical fact!

Research findings recently published in the “Proceedings of the Royal Society” seem to show that there are differences in certain genes between people who dwell on the positive attitudes of seeing life as ‘half-full’ and those who are drawn towards ‘half-empty’ responses.

The mechanism by which this happens is still being investigated but one possibility is that the genes could be affecting the amount of serotonin in the brain. Serotonin affects moods including anger and aggression so higher levels of serotonin would mean better moods.

Another possibility is that a certain area of the brain called the amygdala is seen to be more active in people with the ‘negativity’ genes and this may make such people more inclined to be neurotic worriers with bouts of anxiety.