Individuals with certain psychiatric disorders might be at increased risk of developing a breakthrough COVID-19 infection despite being fully vaccinated, according to a new study from University of California San Francisco.
The study, published Thursday in the online medical journal JAMA Network, analyzed Department of Veterans Affairs data for 263,697 fully-vaccinated individuals. A little over half of those patients had received at least one psychiatric diagnosis in the previous five years for depression, post-traumatic stress disorder, anxiety, alcoholism, substance abuse, bipolar disorder, eating disorders, psychotic disorders, attention-deficit and/or hyperactivity, dissociative identity disorder and eating disorders.
Just above 14% of those included in the study developed a breakthrough COVID infection, and individuals with at least one diagnosed psychiatric disorder had a 7% higher incidence rate of breakthrough cases than those who did not.
When taking into account demographic factors and pre-existing conditions, participants with psychiatric disorders had a 3% increased risk for breakthrough COVID infections in 2021 compared with participants without a psychiatric history.
Researchers further adjusted the modeling to account for differing socio-economic backgrounds, ages, races and even by specific psychiatric diagnoses.
“Across specific psychiatric disorders, each was associated with an increased incidence of breakthrough infection among the full sample in models adjusted for confounders,” researchers wrote in part. “Estimates were attenuated in magnitude but remained significant for most individual disorders when additionally accounting for medical conditions, obesity, and smoking.”
Adjustment disorders, defined by Johns Hopkins as an “emotional or behavioral reaction to a stressful event or change in a person’s life,” and substance use disorders were associated with the highest rates of breakthrough infections. Psychotic disorders, which cause those affected to “lose touch with reality” by way of delusions and hallucinations, were the only classification of disorders not associated with an increased rate of breakthrough COVID-19 infection when adjusted for factors like medical conditions, obesity and smoking across all age groups.
Individuals under the age of 65 with a psychotic disorder actually had a 10% lower chance of developing a breakthrough infection compared to those without a diagnosis, but individuals above the age of 65 with psychotic disorders were 23% more likely to contract COVID despite being vaccinated.
Senior study author Aoife O’Donovan attributed the schism between the two age groups of those diagnosed with psychotic disorders to possibly lower levels of socialization for younger individuals, compared with those above 65 years old who “may be less socially isolated because of their greater burden of ill health and contacts with caregivers.”
The results did begin to diverge when stratified by age in particular, with psychiatric diagnoses “not associated with incidence of breakthrough infection” for younger individuals when fully adjusted for other medical comorbidities.
Older adults with any psychiatric diagnosis – with the only exceptions being posttraumatic stress disorder and alcohol use disorder – were at a higher risk of contracting a breakthrough infection compared to their younger counterparts.
Patients 65 and older diagnosed with substance abuse, psychotic disorders, bipolar disorder, adjustment disorder and anxiety were up to 24% more likely to experience a breakthrough COVID infection compared to those without a psychiatric diagnosis. Individuals with the same mental health conditions under the age of 65 were 11% more likely to contract a breakthrough case.
“Risks for breakthrough infections associated with substance abuse, adjustment disorder, anxiety and post-traumatic stress disorder were all higher in the younger cohort than their peers without a psychiatric diagnosis – 11%, 9%, 4% and 3%, respectively,” the study found.
There are several possible reasons, though not definitively proven, why individuals with psychiatric disorders might have a higher risk of contracting a breakthrough COVID infection. A number of previous studies have shown individuals with poor mental health tend to have “impaired immune function and poor response to vaccines,” suggesting the vaccinations against the SARS-CoV-2 virus might have similarly reduced efficacy for those with psychiatric disorders.
Medical conditions like cardiovascular disease and diabetes, both of which put individuals at increased risk of contracting COVID, are more prevalent among people with psychiatric disorders, another compounding risk factor for the population. And finally, a previous study also conducted by UCSF found that individuals with psychiatric disorders are more likely to engage in certain risk-taking behavior that might also increase their risk of contracting the virus.
“Our research suggests that increased breakthrough infections in people with psychiatric disorders cannot be entirely explained by socio-demographic factors or pre-existing conditions,” O’Donovan said in part. “It’s possible that immunity following vaccination wanes more quickly or more strongly for people with psychiatric disorders and/or they could have less protection to newer variants.”
Researchers noted a couple of limitations with the study, not least of which being the source of the data, as administrative and electronic records can “lack detail and could result in residual confounding or misclassification.” And because the study relied on COVID-19 breakthrough cases as reported to the VA, they may have missed other cases where patients tested at home, at other facilities or were asymptomatic.
The vast majority of those included in the study were males around the age of 66, meaning the data may also be skewed in the direction of that particular population.