Unhappy children may not only suffer from self-esteem issues, but they are also more likely to become materialistic, according to new research.

According to lead study author Suzanna Opree, children who are less satisfied with their lives are more susceptible to believing advertisements that suggest possessions can increase happiness.

Opree, who is a research associate at the University of Amsterdam's School of Communication, defines materialism as "having a preoccupation with possessions and believing that products bring happiness and success."

The study surveyed 466 children and their response to items, measuring materialism. For instance children were instructed to explain how much they like other children based on whether they have more possessions. They were also instructed to rate how happy they were with their lives, homes, parents, friends, school and themselves overall. Additionally, researchers factored in advertisement exposure and gauged how frequently children watched nine television shows that featured a large amount of advertising.

Researchers examined whether the effect of materialism on life satisfaction, or how happy a child is with their life, is dependent on advertising exposure or whether the effect of life satisfaction on materialism is dependent on advertisement exposure.

Data demonstrated that life satisfaction did have an effect on materialism but only if children were frequently exposed to advertisements. The happier a child was the less materialistic that child was whereas an unhappy child was more likely to be materialistic.

Opree believes it has a lot to do with message marketing companies' condition, "Buy this product because it will make you happy or make you more popular."

According to Opree, children are bombarded with a lot of ads. It is estimated the amount of ads children are annually exposed to vary from 10,000 in Britain (from a 2007 study) to 40,000 in the U.S. (from a 2001 study).

Unhappy children are more vulnerable to those ads.

Opree recommends parents help children focus on alternative sources of happiness, such as love, friendship and play, as a means to de-emphasize the role of possessions. It is important to reduce this effect because materialistic children are more likely to be unhappy later in life.

The study was published in Pediatrics.