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That people living with mental illness have a reduced life expectancy

That people living with mental illness have a reduced life expectancy compared with the general population has been extensively documented around the world (Chang et al. 2011; Walker et al. 2015; Plana-Ripoll et al. 2019). Research from Western Australia found that the gap in life expectancy for people with mental illness registered with West Australian mental health services compared with the general population in 2005 was 15.9 years for men and 12.0 years for women (Lawrence et al. 2013). This research also indicated that the mortality gap for people living with mental illness had increased from 1985, by 2.5 years for men and 1.6 years for women since 1985, with the increase largely driven by gains in life expectancy for the general population (Lawrence et al. 2013) . This finding aligns with studies from other high-income countries suggesting that the mortality gap for people with mental illness may be increasing over time, in part due to gains in life expectancy for the general population not experienced (or at least not experienced in equal measure) by those with mental illness and especially SMI (Neilsen et al 2013; Hayes et al 2017; Laursen et al 2019).

Rather than a direct result of mental illness or death by suicide, almost 80% of premature deaths of people with mental illness are due to potentially preventable physical health comorbidities (Lawrence et al. 2013). These include type 2 diabetes, respiratory diseases, cancer and cardiovascular disease (De Hert et al. 2009). Compared to the general population, people with SMI have a 2- to 3-fold risk of developing hypertension and metabolic syndrome and, if under the age of 50, a 3-fold risk of dying from coronary heart disease (De Hert et al. 2009; Osborn et al. 2007). If diagnosed with cancer, people living with SMI experience higher rates of mortality compared to the general population (Launders et al. 2022; Charlesworth et al. 2023).

Substance use and mental illness

Use of alcohol, tobacco and illicit drugs can trigger or worsen mental health issues and are strongly associated with physical health conditions including cancer, cirrhosis, and cardiovascular disease (AIHW 2022).

The relationship between mental illness and substance use is complex. A mental illness may make a person more likely to use drugs as an attempt to self-medicate symptoms associated with their mental illness. Conversely, substance use may be a contributing factor for the initial symptoms of mental illness. Certain substances may cause a substance-induced psychosis which can last for days or weeks after the end of intoxication. However, if someone has a pre-disposition to developing a psychotic illness, such as schizophrenia, the use of illicit drugs may bring on the first episode of what can be a longer-lasting psychotic illness (NDARC 2011). Critically, this does not mean that mental illness necessarily causes substance use and vice versa: common risk factors (such as trauma, personality traits, genetic influences and the childhood environment) may cause substance use and mental illness to independently develop in the same individual (UNODC 2022).

Among people living with mental illness, there are higher rates of alcohol, tobacco and other drug use compared with people without mental illness (refer to Figure PHYS.2).

https://www.aihw.gov.au/reports/ment...mental-illness