A genetic mechanism leading that makes people more or less prone to some psychiatric disorders, including depression was discovered by scientists from the Duke University Medical Center, U.S.
The team found that a variation in a single gene produced different levels of the brain chemical serotonin, which influences mood, emotions, appetite and the ability to sleep. Studies showed that mice with one variant of the gene had serotonin levels 50% to 70% lower than the levels of others.
Dr Xiadong Zhang, the lead researcher on the study, said: "This single genetic difference has a huge impact on serotonin levels, confirming that the gene is fundamental in the synthesis of brain serotonin."
They suggest the enzyme could also affect how patients respond to selective serotonin re-uptake inhibitors (SSRIs), such as Prozac.
The work published in Science journal proposes a test on the usefulness of antidepressant medication. It may also be useful in detection and/or early prediction of different mental disorders.
US President Joe Biden and Iraqi Prime Minister Mustafa Al Qadimi signed an agreement on July 26 to formally end the USA's military presence in the country by the end of the year