Respiratory diseases are an increasingly recognised contributor to premature mortality in people living with serious mental illness (SMI). Although cardiovascular and metabolic risks often dominate clinical attention, recent evidence highlights that lung function decline is both common and clinically meaningful in schizophrenia and bipolar disorder. 

Population-based studies have consistently shown that individuals with SMI face a higher risk of asthma, COPD and pneumonia compared with the general population. These vulnerabilities are shaped by early-life factors—such as prenatal tobacco exposure, low birth weight or childhood adversity—as well as adult patterns including higher smoking rates, metabolic syndrome and sedentary behaviour. 

A recent study in asymptomatic smokers with schizophrenia and bipolar disorder found that one in four had undiagnosed COPD, with many already in moderate or severe stages. Longitudinal follow-up revealed an accelerated decline in FEV₁, substantially faster than that expected in the general population. Other clinical samples also show that early spirometric alterations, including reduced FEV₁ without obstruction, are frequent in both disorders. 

Why does this matter?
 Lung function is a strong predictor of morbidity and mortality. Yet respiratory assessment is rarely incorporated into routine care for people with SMI, despite the availability of simple, affordable tools such as spirometry. Importantly, giving patients personalised information about their respiratory function has been shown to support smoking cessation—still the leading preventable cause of death in this group. 

Strengthening respiratory health assessment—alongside cardiovascular and metabolic screening—offers a clear opportunity to reduce premature mortality in SMI.