Anxiety may be a first world problem - and a young female one at that.

A review of reviews (so calibrate your expectations) in Brain and Behavior finds that women are almost twice as likely to experience anxiety as men, and people from Western Europe and North America are more likely to suffer from anxiety than people from other cultures.

Anxiety disorders are a non-specific blanket term for excessive worry, fear and a tendency to avoid potentially stressful situations including social gatherings. Pretend money estimates claim these disorders cost $42.3 million in the U.S. In the European Union, over 60 million people are affected by anxiety disorders in a given year, likely because of all that worry about cell phones, ugly fruit and GMOs.

Scholars from the University of Cambridge's Institute of Public Health carried out a global review of systematic reviews. Out of over 1,200 reviews, the researchers identified 48 reviews that matched their criteria for inclusion. They found that between 1990 and 2010, the overall proportion of people affected remained largely unchanged, with around four out of every 100 experiencing anxiety. The highest proportion of people with anxiety is in North America, where almost eight out of every 100 people are affected; the proportion is lowest in East Asia, where less than three in 100 people have this mental health problem. 

Women are almost twice as likely to be affected as men, and young individuals -- both male and female -- under 35 years of age also claimed more anxiety than previous generations. The researchers also found that people with other health conditions are often far more likely to also experience anxiety disorders. For example, around one in ten adults (10.9%) with cardiovascular disease and living in Western countries are affected by generalized anxiety disorder, with women showing higher anxiety levels than men. People living with multiple sclerosis are most affected -- as many as one in three patients (32%) also have an anxiety disorder.

According to first author Olivia Remes from the Department of Public Health and Primary Care at the University of Cambridge, "By collecting all these data together, we see that these disorders are common across all groups, but women and young people are disproportionately affected. Also, people who have a chronic health condition are at a particular risk, adding a double burden on their lives."

Obsessive compulsive disorder (OCD) -- which is an anxiety disorder characterized by obsessions and compulsions -- was found to be a problem in pregnant women and in the period immediately after birth. In the general population, only one in a hundred people are affected by OCD, but the proportion with the disorder was double in pregnant women and slightly higher in post-partum women.

However, the analysis also showed that data on some populations was lacking or of poor quality. This was particularly true for marginalized communities, such as indigenous cultures in North America, Australia and New Zealand, and drug users, street youth and sex workers. Anxiety disorders also represent an important issue among people identifying as lesbian, gay, and bisexual; however, there are not enough studies in these populations, and those that have looked at it are of variable quality