Which box do you check in life’s happiness questionnaire? “Very satisfied,” "very dissatisfied,” or something in between? “It depends on the deal that I got,” you may be saying. Well, yes, it does depend somewhat on the deal that you were handed at birth. About thirty to fifty percent you can blame on your parents, if studies on twins are correct.
For some time now we have had studies indicating that our genetic inheritance of the serotonin transporter gene, solute carrier family 6, member 4 (SLC6A4), or 5-hydroxytryptamine transporter: 5-HTT is the key to about twenty percent. (We can put the rest down to weather and taxes.) Serotonin is the happiness hormone and 5-HTT helps carry it, around distributing its largess to our satisfaction.
5-HTT comes in long and short variations, and if you’re asking, “Please, sir, can I have some more?” the arrival of a long train would be better than a short one. Of course you get one from each parent, so you can have two long ones, two short or a long and a short. If you are only half as happy as you think you should be, ask which one short-changed you.
The latest metastudy by De Neve, which is reported in today’s Guardian newspaper (1), was of a large group of US citizens. It adds to the body of evidence that the “glass half full” attitude is partly genetic.
Serotonin also plays a role in cognitive functions such as memory and learning. Ironically it also occurs in some insect venoms and is the cause of the pain when bitten. Maybe just the threat of serotonin injections would make our kids pay attention and learn more in school.
