While the direct effects of climate change on mental health are well-established, less is known about the impact of indirect exposures. This study examined whether individuals with clinically significant symptoms of depression and anxiety experience 1a) greater chronic climate-related stress and 1b) stronger affective responses to an acute climate-related stressor. A further aim was to investigate whether 2) clinically significant symptoms of depression and anxiety are associated with pro-environmental behavior.

N=886 adults from the adult Swiss, German, Austrian, and Liechtenstein resident population completed a pre-registered online study comprising a survey, experiment, and test. The participants were classified as having clinically significant symptoms of depression or not, and as having clinically significant symptoms of anxiety or not, based on validated cutoff scores for the Patient Health Questionnaire (PHQ-9) and General Anxiety Disorder Scale (GAD-7), respectively. To answer research question 1a), questions on chronic climate-related stress, solastalgia, and pre-traumatic stress were answered (survey). To answer research question 1b), acute climate stress was induced by a climate change video, and affective responses measured using the Positive Affect Negative Affect Schedule (PANAS) and the State-Trait-Anxiety-Inventory (STAI-S) (experiment). To answer research question 2), pro-environmental behavior was measured using the Pro-Environmental Behaviour Scale (PEBS) (survey) and the Work for Environmental Protection Task (WEPT; test).

Of the N=886 participants, n=244 and n=183 had clinically significant symptoms of depression and anxiety, respectively. Individuals with clinically significant symptoms of depression and anxiety had higher levels of solastalgia and pre-traumatic stress than those without depression and anxiety symptoms (all p < 0.001) (survey). Individuals with clinically significant symptoms of depression showed a smaller increase in negative affect in response to acute climate stress ( p =0.016) (experiment). Pro-environmental behavior did not differ between groups (survey and test).

Our findings indicate that individuals with clinically significant symptoms of depression and anxiety experience greater chronic climate change-related distress. At the same time, individuals with clinically significant symptoms of depression exhibit blunted responses to acute climate stress. Importantly, neither clinically significant symptoms of depression nor anxiety were associated with pro-environmental behavior.