Depression, anxiety affects every society and country in the world,
The findings come from the world's most comprehensive study of these mental states, carried out by researchers from the University of Queensland, Australia.
In two separate studies of anxiety disorders and major depressive disorder (that is, clinical depression) researchers found that surveys of clinical anxiety and depression have been conducted across 91 countries, involving more than 480,000 people.
Clinical anxiety affected around 10 percent of people in North America, Western Europe, Australia and New Zealand compared to about eight percent in the Middle East and six percent in Asia.
The opposite was true for depression, with people in Western countries least likely to be depressed. Depression was found to be lowest in North America and highest in some parts of Asia and the Middle East, according to a Queensland statement.
About nine percent of people have major depression in Asian and Middle Eastern countries, such as India and Afghanistan, compared with about four percent in North and South America, Australia, New Zealand and east Asian countries including China, Thailand and Indonesia.
Alize Ferrari, study co-author, said findings suggested that depression appeared to be higher in parts of the world where conflict is occurring.
However, she warns that it can be difficult to obtain good quality data from some low and middle income countries.
Amanda Baxter, who led the study, also urged caution while comparing mental disorders across different countries.
"Measuring mental disorders across different cultures is challenging because many factors can influence the reported prevalence of anxiety disorders," said Baxter.