Thinking clearly about climate change and mental health

Abstract

Objective To examine the quality and strength of evidence for an association between temperature increases caused by climate change and suicide used in policy documents to advocate for radical changes to healthcare systems in pursuit of decarbonisation. Method The designs of articles collected in a systematic review which concluded that there was an association between climate change and increased rates of suicide were analysed for their capacity to support this conclusion. Complete US data covering temperatures and suicide rates between 1968 and 2004 was aggregated and analysed using linear regression to evaluate evidence for an association between temperature and suicide. Results None of the articles collected in the review has a design capable of investigating whether there is an association between temperature increases caused by climate change and rates of suicide. At the national level increased annual US temperatures were associated with a decrease in the rate of suicide, and at the state level it was common for high average temperature states to have low rates of suicide and vice versa. Conclusions Policy recommendations for radical changes in healthcare services have been based on misrepresented evidence. Policy makers should beware of recommendations that ignore scientific evidence to pursue faith-based goals.

Response to ‘Thinking clearly about climate change and mental health’

“…It is disappointing that Australasian Psychiatry has published an article by its deputy editor without disclosing any conflict of interest, particularly as the article insinuates biased presentation of evidence in the RANZCP statement on climate change. 1 , 2…”

“…Amos’ article examined two of the 35 publications referenced in the RANZCP position statement ‘Mental health impacts of climate change’ and concluded that they were inadequate to support the statement. 1 He noted that although 16 of 17 observational studies found positive relationships between higher temperatures and increased rates of suicide, observational research cannot prove that climate change increases suicide rates. 1 However, the studies clearly demonstrate trends and provide adequate evidence for Thompson et al to support the assertion that rates of suicide are likely to increase in line with climate projections.…”

“… 1 He noted that although 16 of 17 observational studies found positive relationships between higher temperatures and increased rates of suicide, observational research cannot prove that climate change increases suicide rates. 1 However, the studies clearly demonstrate trends and provide adequate evidence for Thompson et al to support the assertion that rates of suicide are likely to increase in line with climate projections. The most recent data reviewed by Thompson et al is from 2012, and climate change and understanding of its impacts have accelerated since then.…”

“…Amos re-analysed data published by Burke et al that investigated associations between temperatures and suicide across the USA, 4 although they did not provide access to their statistical analysis. 1 Amos used whole states rather than suburbs, and years rather than months as units of analysis, and this aggregated data showed an inverse relationship between temperatures and suicide rates. 1 Aggregation masks the effects of extreme weather events that contribute to worsened health outcomes, and Amos’ finding does not undermine the evidence that climate change is increasing suicide rates.…”

“… 1 Amos used whole states rather than suburbs, and years rather than months as units of analysis, and this aggregated data showed an inverse relationship between temperatures and suicide rates. 1 Aggregation masks the effects of extreme weather events that contribute to worsened health outcomes, and Amos’ finding does not undermine the evidence that climate change is increasing suicide rates. 4 …”