More than 500 Helsinki residents of Russian, Somali and Kurdish background took part in the study, released on Wednesday by the National Institute for Health and Welfare (THL).

The report indicates that immigrants on average pose less of a financial burden on the public health system than native-born Finns, as they simply tend to go to the doctor less. However it suggests that perhaps they should make more use of Finland's free medical services.

The study finds that untreated mental health issues are common among foreign-born city dwellers, as well as physical disabilities.

Coordinating the research at the THL was Maryam Fathollahi, a Kurd who came to Finland from Iran with her family as a refugee just over five years ago. Now she has been helping to gather information from other Kurdish immigrants about their health.

Before coming to Finland, she says, many of them suffered persecution and imprisonment. Nearly all had trauma symptoms, while nearly half of Kurdish men had been tortured in their home countries.

Still, few have sought mental health treatment. Many say this is because it is difficult to find such care, while language often poses a problem.

Although the number of foreign doctors and psychologists is on the rise, Anna-Liisa Lyytinen of the city's health department says it is not realistic to be able to offer native-language services to all immigrants. Instead, she says, there will have to be a greater reliance on interpreters.