A new study says that maternal depression can aggravate asthma symptoms in children.

Scrutinising data from interviews with 262 mothers, Johns Hopkins investigators noted that children, whose mothers had more depressive symptoms, were likely to have more frequent asthma symptoms.

Conversely, children whose mothers reported fewer depressive symptoms had less frequent asthma symptoms.

"Even though our research was not set up to measure just how much a mom's depression increased the frequency of her child's symptoms, a clear pattern emerged in which the latter followed the earlier," says Senior Investigator Kristin Riekert, Paediatric Psychologist at the Johns Hopkins Adherence Research Centre.

Previous research has shown that children with chronic health conditions fare worse if their main caretaker is depressed.

"Intuitively, it may seem that we're dealing with a chicken-egg situation, but our study suggests otherwise," Riekert says.

According to the CDC, Asthma is the leading paediatric chronic illness in the US, affecting 6.5 million children under 18 years. The findings of the study were published online in the Journal of Paediatric Psychology.