Review question / Objective: The aim of the review is to synthesise findings from quantitative studies that investigate ecological grief, eco-anxiety, and climate-anxiety in relation to self-reported mental health. Population of interest: The general adult population aged 18 years. Exposure (risk factor): The exposure is defined as the presence of any ecological grief, eco-anxiety, and/or climate-anxiety that is quantified either before, concurrently, or after a mental health symptom (e.g. depression, and/or anxiety - see Outcomes). As ecological grief, eco-anxiety, and climate-anxiety are relatively new concepts that lack a standard definition, we will include validated and emerging unvalidated self-report measures of these constructs, as well as closely related constructs" solastalgia, eco- and climate grief, eco- and climate-guilt, eco- and climate-distress, eco- and climate-despair, eco- and climate-worry. Ineligible exposures are detrimental environmental events (e.g. flood, bushfire, drought) or climatic conditions (e.g. ambient temperatures) or distress related to psychosocial impacts of environmental events (e.g. loss of income or housing due to landslide). Comparator: The general adult population aged 18+ without ecological grief, eco-anxiety, and/or climate-anxiety or related constructs as defined above in Exposure. Outcome: The primary outcomes are mental health symptoms quantified by validated self-report measures of depression, anxiety, stress.