Historical trauma
Indigenous historical trauma (IHT) is the trauma that can accumulate across generations and develop as a result of the historical ramifications of colonization and is linked to mental and physical health hardships and population decline.[154] IHT affects many different people in a multitude of ways because the Indigenous community and their history are diverse.
Many studies (such as Whitbeck et al., 2014;[155] Brockie, 2012; Anastasio et al., 2016;[156] Clark & Winterowd, 2012;[157] Tucker et al., 2016)[158] have evaluated the impact of IHT on health outcomes of Indigenous communities from the United States and Canada. IHT is a difficult term to standardize and measure because of the vast and variable diversity of Indigenous people and their communities. Therefore, it is an arduous task to assign an operational definition and systematically collect data when studying IHT. Many of the studies that incorporate IHT measure it in different ways, making it hard to compile data and review it holistically. This is an important point that provides context for the following studies that attempt to understand the relationship between IHT and potential adverse health impacts.
Some of the methodologies to measure IHT include a "Historical Losses Scale" (HLS), "Historical Losses Associated Symptoms Scale" (HLASS), and residential school ancestry studies.[154]: 23 HLS uses a survey format that includes "12 kinds of historical losses", such as loss of language and loss of land and asks participants how often they think about those losses.[154]: 23 The HLASS includes 12 emotional reactions, and asks participants how they feel when they think about these losses.[154] Lastly, the residential school ancestry studies ask respondents if their parents, grandparents, great-grandparents, or "elders from their community" went to a residential school to understand if family or community history in residential schools is associated with negative health outcomes.[154]: 25 In a comprehensive review of the research literature, Joseph Gone and colleagues[154] compiled and compared outcomes for studies using these IHT measures relative to the health outcomes of Indigenous peoples. The study defined negative health outcomes to include such concepts as anxiety, suicidal ideation, suicide attempts, polysubstance abuse, PTSD, depression, binge eating, anger, and sexual abuse.[154]
The connection between IHT and health conditions is complicated because of the difficult nature of measuring IHT, the unknown directionality of IHT and health outcomes, and because the term Indigenous people used in the various samples comprises a huge population of individuals with drastically different experiences and histories. That being said some studies such as Bombay, Matheson, and Anisman (2014),[159] Elias et al. (2012),[160] and Pearce et al. (2008)[161] found that Indigenous respondents with a connection to residential schools have more negative health outcomes (e.g., suicide ideation, suicide attempts, and depression) than those who did not have a connection to residential schools. Additionally, Indigenous respondents with higher HLS and HLASS scores had one or more negative health outcomes.[154] While there are many studies[156][162][157][163][158] that found an association between IHT and adverse health outcomes, scholars continue to suggest that it remains difficult to understand the impact of IHT. IHT needs to be systematically measured. Indigenous people also need to be understood in separate categories based on similar experiences, location, and background as opposed to being categorized as one monolithic group.[154]