Brain chemistry as a determinant of mood
All the happiness research concludes that happiness is dispositional: No matter what happens to us, we return after a while to our genetically pre-set level of happiness. And happiness is also a strong differentiator of liberals and conservatives. So liberals are born unhappy, which is why they are always wanting to change things in the futile search for a system that they will be happier with. The research reported below is concerned with a closely related topic, pessimism/optimism so we may be getting closer to seeing exactly what makes liberals the angry and irrational creatures they are
If you find it hard to look on the bright side and your glass is half-empty rather than half-full, blame your lateral habenula.
Scientists say chemicals in this small part of the brain are crucial to feelings of disappointment. If the chemistry is right, we may find it easier to brush off the bad times. But if it is out of balance, we may feel set-backs more keenly.
Researcher Roberto Malinow said: ‘The idea that some people see the world as a glass half-empty has a chemical basis in the brain.’
To work out why some people find it hard to be optimistic, the professor looked at the chemistry of a lateral habenula, a tiny area deep inside the brain.
Studies on monkeys have shown the lateral habenula becomes very active when the creatures are denied a fruit juice they are expecting.
In experiments on rats and mice, Professor Malinow showed the balance of two brain chemicals in the region to be key.
One, called glutamate, ramps up activity in the area, while the other, GABA, dampens it down.
Rats with depression made less GABA than others. But when they were given an anti-depressant, levels increased.
It is thought pessimists naturally make less GABA. This would make them feel knock-backs more deeply – and so expect bad things to happen more often.
The finding suggests making enough GABA is crucial to dealing with disappointment.
Professor Malinow, of the University of California, San Diego, said: ‘What we have found is a process that may dampen the brain’s sensitivity to negative life events.’
His research, published in the journal Science, doesn’t just help explain why some people are more pessimistic than others – it could also help in the search for new treatments for depression.