A new study reports that kids with gloomy personalities can develop more positive outlooks when they're parented in a warm, positive environment, according to U.S. News & World Report.

The study focused on nearly 1,900 children, aged 9 to 15, who all had a gene variation that predisposed them to lower serotonin levels in the brain. Low serotonin levels have previously been linked with bad moods and even depression.

In the first experiment, researchers had parents of these "genetically susceptible" children report on the degree to which they used positive or supportive parenting techniques, and in the second experiment, parenting behaviors were observed in a laboratory. Finally, researchers had the children themselves report their own perceptions of warm, positive parenting.

The results indicated that youths were more likely to maintain happier emotions when exposed to positive parenting, while those who experienced unsupportive parenting showed fewer positive emotions.

"A weed will grow anywhere," said Benjamin Hankin, an associate professor of clinical child and developmental cognitive neuroscience psychology at the University of Denver. "But if you're an orchid, you're probably more reactive and responsive to your environment. If you have a really negative, punishing environment, you're probably not going to grow up to be a beautiful orchid."

Marta Flaum, a child psychologist in Chappaqua, N.Y., said the study highlights the importance of environment in determining whether children will become happier and more successful adults.

"As science becomes more sophisticated, we're better able to identify these genetic or biologic markers and can predict what's going to happen in kids," she said. "We know how important early intervention is, and this study points in a direction to help us intervene."

Hankin added that most people are unaware whether their genes predispose their children to have lower brain serotonin levels, but that children who seem to be chronically moody are likely to be affected.

The study was published in the journal Translational Psychiatry.

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