The researchers came to this conclusion through an analysis of search query data that Google made available through Google Trends. As described in a paper published in the American Journal of Preventive Medicine, they found that search queries about a broad spectrum of mental health issues followed seasonal patterns. The queries were consistently higher in the winter than in the summer, both in the United States and in Australia.
"Information seeking on Google across all major mental illnesses and/or problems followed seasonal patterns similar to those found for seasonal affective disorder," the paper states. "These are the first data published on patterns of seasonality in information seeking encompassing all the major mental illnesses, notable also because they likely would have gone undetected using traditional surveillance."
[ What's the point of compliance if it looks like this? Read The Freedom From Information Act. ]
The researchers assessed search queries from the U.S. and Australia over a four-year period, from 2006 to 2010. The terms covered included: ADHD (attention deficit-hyperactivity disorder); anxiety; bipolar; depression; anorexia or bulimia (eating disorders); OCD (obsessive-compulsive disorder); schizophrenia; and suicide.
The research data indicates that eating disorder searches declined 37% in U.S. summers, compared to winters, and declined 42% in Australian summers. Schizophrenia searches fell 37% during U.S. summers and 36% in Australia. Searches for suicide dropped 24% in U.S. summers and 29% in Australian summers. Searches related to other disorders showed similar patterns.
James Niels Rosenquist, a psychiatrist at Massachusetts General Hospital and one of the four co-authors of the study, said in a statement that while some mental health conditions, like seasonal affective disorder, have an established seasonal component, finding a broad seasonal fluctuation across the spectrum of mental illness was unexpected.
The paper suggests that these findings argue for further examination of seasonal deficiencies in vitamin D, omega 3 (associated with depression, bipolar disorder and schizophrenia) and exercise as possible ways to improve mental health.
However, the paper is careful to state that search queries are not a replacement for traditional public health surveillance. Rather, they represent an additional avenue of research that avoids some of the problems with voluntary reporting tools.
"The Internet is a stigma- and cost-reducing venue to help screen and treat those who search for but may not bring problems to the attention of their clinicians," the paper stated. "Internet-based treatment programs show promise; however, many search engine results are of questionable quality."
One problem with using search queries to track mental health concerns is that searches may be influenced by advertising. Also, mental health issues without a significant query volume may go unnoticed.
"The Internet is a game changer," said lead investigator John W. Ayers, of the Graduate School of Public Health at San Diego State University, in a statement. "By passively monitoring how individuals search online we can figuratively look inside the heads of searchers to understand population mental health patterns."
Ayers received funding for this project from Google.org. Funding was also provided by the Graduate Research Fellowship Program from the National Science Foundation.
Google has been providing search data for public health purposes since 2008 when its philanthropic arm, Google.org, launched Google Flu Trends, a map that shows flu-related searches throughout the U.S. The company last year shut down a related service, Google Flu Trends Vaccine Finder, as a result of its plan to focus on fewer projects.