Still the experts are puzzled as to why the increase only pertained to white Americans.  One theory being offered is that whites had been doing relatively well in terms of economic security until recently, and the downturn in the economy has left them feeling helpless.

The thought is that since the Hispanic and the African American populations had not had the same successes in the past as the whites, they were more resilient during the bad economy, and were better equipped emotionally to weather the storm.

Experts also add that since the trend was not recorded in other countries, it is clearly a problem among the middle-aged whites in the United States.

The American Foundation for Suicide Prevention had previously reported that in 2013, the highest rate of suicide was among the 45-64 year-old age group, with the second highest group being those 85 and older.

The findings of the research by Deaton and Case were published by the Proceedings of the National Academy of Sciences.

For his work on the study of poverty, Deaton was awarded the 2015 Nobel Prize in Economics.