Research showed that online screening surveys overestimate the prevalence of disorders such as PTSD, with diagnostic interviews providing a more accurate picture
"Many of the validated screening tools widely used in mental health research favour sensitivity over specificity and therefore have low positive predictive value, and thus are likely to overestimate the true prevalence of mental disorders.” Authors of Lancet paper on prevalence of PTSD and common mental health disorders among health care workers
One in 12 health care workers (8%) developed post-traumatic stress disorder (PTSD) during the Covid pandemic, according to a paper published in the Lancet.
The researchers, from King’s College London and University College London, carried out a two-phase, cross-sectional study consisting of diagnostic interviews within a larger longitudinal cohort of health care workers. In the first phase, health care workers in 18 NHS England trusts were recruited.
During this first phase, carried out between April 2020 and January 2021, participants completed online screening surveys to assess the prevalence of common mental disorders. The screening sample consisted of 23,462 people. The results suggested that just over half of the sample (52·8%) experienced generalised anxiety disorder or depression, while 24.5% experienced PTSD.
In the second phase, between March and August 2021, the research team recruited a subset of respondents who had completed the survey. They then conducted diagnostic interviews with 243 individuals to establish the prevalence of common mental disorders, and diagnostic interviews with 94 individuals specifically looking at PTSD.
The general diagnostic interviews, which used a scale called Clinical Interview Schedule-Revised (CIS-R), found that 14.3% of the sample experienced generalised anxiety disorder while 13.7% experienced depression. The combined population prevalence of generalised anxiety disorder and depression was 21.5%.
The PTSD interviews, which used the Clinician Administered PTSD Scale for DSM-5 (CAPS-5), found that 7·9% experienced PTSD.
The researchers’ findings were striking because of the difference in results between the online screening tool and the diagnostic interviews, which showed a much lower prevalence of the three conditions. They note that much of the evidence for mental health disorders amongst health care professionals comes from online surveys using screening tools. “This method allows for relatively rapid and low-cost data collection with large samples,” they write. “However, many of the validated screening tools widely used in mental health research favour sensitivity over specificity and therefore have low positive predictive value, and thus are likely to overestimate the true prevalence of mental disorders.”
In contrast, diagnostic interviews carried out by trained interviews using structured tools are considered the “gold standard for identification of mental disorders,” the researchers write. They are, however, “more resource intensive”.
The authors argue that their findings “suggest that the screening tools with commonly used cutoff scores, utilised by many studies, substantially overestimate the prevalence of mental disorders.” They argue that researchers who use self-report screening tools in novel contexts should “carefully consider cutoff scores on screening tools, and ideally complete further validation work to correctly calibrate measures to be appropriately sensitive.” It can, they argue, “be unhelpful to report results from self-report tools since they might cause alarm and inappropriate allocation of scarce resources.”
They conclude that 21.5% of health care workers “meet criteria for a diagnosable mental disorder”, adding: “Although evidence suggests that health-care workers operating in challenging environments will often work through potentially traumatic events without the need for clinical intervention, considering the known association between diagnosable mental disorders and poor workplace functioning, we suggest that it might be helpful to provide treatment promptly for health-care workers with diagnosable mental disorders.”
This research is valuable for two reasons. It highlights the incidence of mental health disorders such as PTSD amongst health professionals, and the need to treat those who develop such disorders. It also illustrates the problems inherent in using screening tools that, while relatively cheap and easy to administer, may greatly over-estimate the prevalence of mental health problems. Using a more sensitive, if more resource-intensive, tool can enable the NHS to identify more accurately those health care workers in need of professional support.