Monitoring population mental illness trends has been an historic challenge for scientists and clinicians alike. Typically, telephone surveys are used to try to glimpse inside the minds of respondents, but this approach is limited because respondents may be reluctant to honestly discuss their mental health. This approach also has high material costs. As a result, investigators have not had the data they need.
"The Internet is a game changer," said lead investigator John W Ayers, PhD, MA, of the Graduate School of Public Health at San Diego State University. "By passively monitoring how individuals search online we can figuratively look inside the heads of searchers to understand population mental health patterns."
Using Google's public database of queries, the study team identified and monitored mental health queries in the United States and Australia for 2006 through 2010.
All queries relating to mental health were captured and then grouped by type of mental illness, including ADHD (attention deficit-hyperactivity disorder), anxiety, bipolar, depression, eating disorders (including anorexia or bulimia), OCD (obsessive compulsive disorder), schizophrenia, and suicide.
Using advanced mathematical methods to identify trends, the authors found all mental health queries in both countries were consistently higher in winter than summer.
Searches for suicide
The research showed eating disorder searches were down 37% in summers versus winters in the US, and 42% in summers in Australia. Schizophrenia searches decreased 37% during US summers and by 36% in Australia.
Bipolar searches were down 16% during US summers and 17% during Australian summers; ADHD searches decreased by 28% in the US and 31% in Australia during summertime. OCD searches were down 18% and 15%, and bipolar searches decreased by 18% and 16%, in the US and Australia respectively.
Searches for suicide declined 24% and 29% during US and Australian summers and anxiety searches had the smallest seasonal change – down 7% during US summers and 15% during Australian summers.
While some conditions, such as seasonal affective disorder, are known to be associated with seasonal weather patterns, the connections between seasons and a number of major disorders were surprising. "We didn't expect to find similar winter peaks and summer troughs for queries involving every specific mental illness or problem we studied, however, the results consistently showed seasonal effects across all conditions – even after adjusting for media trends," said James Niels Rosenquist, MD, PhD, a psychiatrist at Massachusetts General Hospital.
"It is very exciting to ponder the potential for a universal mental health emollient, like Vitamin D (a metabolite of sun exposure). But it will be years before our findings are linked to serious mental illness and then linked to mechanisms that may be included in treatment and prevention programmes," said Ayers. "Is it biologic, environmental, or social mechanisms explaining universal patterns in mental health information seeking? We don't know."
"Our findings can help researchers across the field of mental health generate
additional new hypotheses while exploring other trends inexpensively in
real-time," said Benjamin Althouse, a doctoral candidate at Johns Hopkins
Bloomberg School of Public Health and researcher on the study. "For instance,
moving forward, we can explore daily patterns in mental health information
seeking … maybe even finding a 'Monday effect.' The potential is