How does having too many siblings affect teens' mental health?

A new study of children in the United States and China found that the more siblings teens have, the greater the impact on their happiness and poorer mental health.

A team from the United States and China analyzed data on thousands of high school students and assessed their mental health to determine the impact of having siblings on their health.

“What we found is that when you combine all the evidence, the impact of siblings on mental health is more on the negative side than the positive side,” Doug Downey, the study's lead author, said in a statement.

In China, only children reported having the best mental health, and in the United States, those without a sibling had similar mental health.

US data found that those with the worst mental health were those with older siblings and siblings close in age.

But it's not the name-calling or hair-pulling that seems to worsen teens' mental health. Experts believe the increase in siblings leading to poor mental health is largely due to "resource dilution".

"If you think of parental resources as a pie, having one child means he or she gets all the pie, meaning all the attention and resources of the parents," Downey explained. "But when you add more siblings, each child gets less resources and attention from the parents, and that may Impact on their mental health.

Children from families associated with the greatest social and economic advantages have the best mental health.

However, other studies have shown that having more siblings is associated with better social skills and a lower likelihood of divorce.

“This combination of results cannot be easily explained,” Downey said. “We still have more to learn about the influence of siblings. This is especially important now that the United States and other countries have low fertility rates. Understanding the consequences of growing up with fewer or no siblings is important.” "Their presence at all is an increasingly important social issue."

A recent study in Germany found that people who suffered from tension headaches or migraines also had inflamed and tense muscles in their neck.

Previous studies have found links between neck stiffness and head pain, but they relied on patients' descriptions or evaluations by physical therapists, rather than objectively measuring what's happening inside the neck muscles.

But now, using a new type of MRI called T2 mapping, researchers at the Technical University of Munich have found that people who suffered from tension headaches and migraines also had more tension and fluid buildup (a marker of inflammation) in the neck muscles.

The study of 50 people — 28 with tension headaches or migraines, and 22 without — focused on the trapezius muscle, a diamond-shaped muscle that runs from the back of the neck down through the shoulders and upper back.

The study showed that neck muscles take a little longer to relax in people with migraines, due to higher levels of fluid in those muscles, Headache and Pain reported.

The results, presented at the recent Radiological Society of North America conference, showed that the highest levels of inflammation were recorded in people suffering from tension headaches and migraines.

While the research is at an early stage, this could provide a new way to measure whether neck pain is contributing to a person's headaches, and open up new drug-free treatment options.