Tracking search engine queries for suicide in the United Kingdom, 2004–2013

Highlights

• We examine trends in web searches for suicide and suicide risk factors in the UK.

• We test associations between suicide-related searches and suicide rates in the UK.

• Cyclical pattern is observed in suicide-related and depression-related searches.

• Strong associations observed for suicide searches and suicide rates in youth.

• Internet use may be one of many factors informing suicide ideation or methods.

Abstract

Objectives

First, to determine if a cyclical trend is observed for search activity of suicide and three common suicide risk factors in the United Kingdom: depression, unemployment, and marital strain. Second, to test the validity of suicide search data as a potential marker of suicide risk by evaluating whether web searches for suicide associate with suicide rates among those of different ages and genders in the United Kingdom.

Study design

Cross-sectional.

Methods

Search engine data was obtained from Google Trends, a publicly available repository of information of trends and patterns of user searches on Google. The following phrases were entered into Google Trends to analyse relative search volume for suicide, depression, job loss, and divorce, respectively: ‘suicide’; ‘depression + depressed + hopeless’; ‘unemployed + lost job’; ‘divorce’. Spearman's rank correlation coefficient was employed to test bivariate associations between suicide search activity and official suicide rates from the Office of National Statistics (ONS).

Results

Cyclical trends were observed in search activity for suicide and depression-related search activity, with peaks in autumn and winter months, and a trough in summer months. A positive, non-significant association was found between suicide-related search activity and suicide rates in the general working-age population (15–64 years) (ρ = 0.164; P = 0.652). This association is stronger in younger age groups, particularly for those 25–34 years of age (ρ = 0.848; P = 0.002).

Conclusions

We give credence to a link between search activity for suicide and suicide rates in the United Kingdom from 2004 to 2013 for high risk sub-populations (i.e. male youth and young professionals). There remains a need for further research on how Google Trends can be used in other areas of disease surveillance and for work to provide greater geographical precision, as well as research on ways of mitigating the risk of internet use leading to suicide ideation in youth.

Introduction

Suicide rates have long been viewed as an early warning sign of wider social, political, or economic distress.1, 2, 3 Yet delays inherent in collection and analysis of suicide surveillance often take several years before such data become available. For example, suicide rates for 2013 in England and Wales were not published until February 2015⁴ while, in other countries, delays are even longer. The most recent data for the entire Belgian population are from 2008.⁵

Recently efforts have been made to take advantage of new data created by people's engagement with social media and search engines. Infectious disease epidemiologists have drawn on internet search data to provide early warning of potential outbreaks,^6,7 such as by tracking search engine queries relevant to infectious diseases, including influenza,⁸ HIV,⁹ and gastroenteritis.¹⁰ These applications have now gone beyond infectious disease, from monitoring interest in abortion¹¹ to electronic cigarettes.¹²

Prior academic evidence suggests that this approach may also be fruitful for mental health and suicide epidemiology.^13,14 Using web search engines for premeditating suicide is not unheard of in the general public. Even in the case of the tragic Germanwings plane crash in the French Alps this spring, German prosecutors revealed that the pilot, Andreas Lubitz, had conducted internet research on ‘cockpit doors’ and ‘suicides’ days before the crash.¹⁵

However, for search data to be useful in population health research, there are remaining questions about their validity. In particular, there are concerns about representativeness of data, especially if they fail to capture the intentions of vulnerable groups that may not have routine access to search engines. A recent American study by McCarthy¹⁴ matched Google internet search engine activity to US suicide rates reported by the Centers of Disease Control (CDC), finding a strong negative correlation with suicide rates in the general US population but a strong positive correlation with rates among youth. McCarthy¹⁴ also found a cyclical trend in search activity for suicide and searches for suicide risk factors (e.g. depression) that correlated with seasonal patterns in suicides, but only in individuals aged 15–24 years of age. In addition, there was no acknowledgement that search activity may vary by gender. Lastly, no tests were employed to determine the significanceof association between search activity and suicide rates.

Thus far, McCarthy's results have not been replicated in other countries and specifically, Western industrialised countries. In this paper we have two specific aims. First, we sought to determine if the cyclical trend seen in the USA was also evident for search activity related to suicide and three common suicide risk factors in the United Kingdom: depression,16, 17 unemployment,2, 18, 19, 20, 21 and marital strain.22, 23, 24 Second, we test the validity of suicide search data as a potential marker of suicide risk by evaluating whether web searches for suicide associate with suicide rates among those of different ages and genders in the United Kingdom.