Stress is everywhere. While some stress is unavoidable, and in some cases even beneficial, too much stress can lead to a wide range of negative health outcomes. Individuals and healthcare providers can manage stress, but first they have to recognize and measure it. That is why Creyos Health now includes the Perceived Stress Scale (PSS, also known as the PSS-10)—a widely-used instrument for measuring a patient’s perception of stress. The PSS is available now for all CBS Health customers, so that nearly all types of healthcare providers can better understand a patient’s current state and track the beneficial effects of treatment.

What is the PSS, and how is it used?

The PSS asks patients to share how often stress-related thoughts or feelings occurred in the past month. For example, one item asks “In the last month, how often have you felt that you were unable to control the important things in your life?”

Adding up the responses on the PSS results in a total score, with higher scores indicating greater stress. In CBS Health’s implementation of the questionnaire, patients with scores from 14 to 25 are considered to have moderate stress, and scores above 27 indicate high perceived stress.

The PSS specifically asks about subjective symptoms, hence the “perceived” part of its name. Two patients may have had the same experiences or events happen to them, but some individuals may not perceive them as stressful, while others would—the PSS aims to capture that stress level rather than any particular experiences.

The strong reliability of the PSS has been demonstrated by several studies (see Lee, 2012), and validity has been established by showing that PSS scores predict a broad range of outcomes known to be associated with stress, such as mental health, psychosomatic symptoms, and health service utilization (see Cohen & Williamson, 1998, and Baik et al., 2019).

Scores on the PSS do not suggest a particular diagnosis or course of treatment, but are meant as an aid to quantify a patient’s level of perceived stress and measure improvement over time.

How is stress related to cognition?

Some stress is normal, and brief or mild stress can even be beneficial. In a fast-paced or potentially dangerous situation, stress prepares the body to act with a faster pulse, more oxygen intake, muscles ready to move, and a brain ready to think—yet those same symptoms can disrupt the body’s other systems if the stress sticks around for too long. Indeed, research has revealed that the relationship between stress and cognition is not as simple as “more stress is bad.” Stress researchers have proposed a curved relationship between stress and performance, with very low amounts of stress associated with poor performance due to lack of arousal, medium amounts of stress at the peak of the curve, and high amounts of stress again leading to impaired performance.

The inverted-U relationship between stress and performance on a Stroop (Double Trouble) task—performance was best when stress was moderate and controllable. Adapted from Henderson et al., 2012.

This curve has been called “the infamous inverted U” (Staal, 2003), because while it is a widely used framework supported by some studies, it has become apparent that the relationship is even more complex than that. In addition to the intensity, duration, and controllability of stress, other individual factors, such as age, gender, and personality can affect which level of stress is motivating, and which level will interfere with daily tasks (Sandi, 2013). Because of this complexity, it is important to measure an individual patient’s stress and cognition, in order to aid in diagnosis of mental health conditions, predict whether stress reduction programs will be effective, and fully quantify the mental health outcomes of interventions such as therapy, medication, and rehab.

Which healthcare providers should measure perceived stress with the PSS?

Stress plays a role in almost any mental or physical health condition, as well as in the lives of healthy people looking to optimize their quality of life. PSS scores, then, may be a useful data point for almost any healthcare practitioner, even if stress is not the primary outcome of interest.

For example, a key validation metric for the PSS is its relationship with anxiety and depression. Baik et al., 2017, found strong correlations between scores on the PSS and scores on the GAD-7 and PHQ-9, which are also available in CBS Health to measure anxiety and depression, respectively. Stress plays a role outside of mental health practices as well, as it is a risk factor for recovery or quality of life in many physical health conditions, such as exacerbation of multiple sclerosis (Mohr et al., 2004). Stress can also increase the risk of developing infectious disease (Glaser & Kiecolt-Glaser, 2005)—a particularly relevant link in the context of the ongoing COVID-19 pandemic.

Treatments from healthcare providers may affect more than one type of symptom. By collecting baseline, before-and-after, and longitudinal PSS scores alongside other health metrics and CBS cognitive function results, providers can get a full picture of the causes of patient concerns and the full effects of treatment.

Delivering a digital version of the Perceived Stress Scale in CBS Health

The PSS is available now, and free for all CBS Health clients. Including the PSS in a CBS Health protocol is easy. The scale can be sent as a standalone assessment, or as a part of a series of cognitive tasks and other health questionnaires. When creating a protocol within CBS Health, click the Questionnaires section, then check off the Perceived Stress Scale (PSS). You can check additional questionnaires or sets of cognitive tasks to create a protocol with a seamless patient experience that can be completed in one integrated flow.

For detailed instructions on administering questionnaires within CBS Health, please see our previous blog post on administering the PHQ-9.

The version of the PSS included in CBS Health has the advantage of being fully digital. The questionnaire can be administered in just a few clicks, and requires no special training. The results are scored instantly, and if a patient completes the PSS more than once, results are added to the patient’s report in order to track changes in response to treatments or to monitor for variations over time. For the patient, completing the questionnaire only takes five minutes, and can be taken from any location with one click—no registration or login required. With minimal effort, both the healthcare provider and patient benefit from the valuable information provided by a standardized perceived stress scale.

PSS billing procedures in the United States

Please note: Cambridge Brain Sciences cannot determine your eligibility for reimbursement and does not assume responsibility over the outcome of any claims. The CPT code(s) noted below to report the services provided will depend on other procedures performed, associated CCI edits, and other factors. Please contact your local payer to determine whether you qualify for these codes, and if any additional coding and coverage guidelines exist, such as which providers can perform the service, limits on billable time, or if the use of a modifier is required or allowed.

Providers utilizing the PSS may be eligible for reimbursement through CPT code 96127, described as the following by the Centre for Medicare and Medicaid Services (CMS): Brief emotional/behavioral assessment, with scoring and documentation, per standardized instrument.

As per the latest guidelines from the American Medical Association, this code is also telehealth-approved. Usage limits and reimbursement amounts vary by state, payer types, and potentially other factors, though the average reimbursement value can range anywhere from $4–$8. When administering the PSS alongside other mental health screening instruments, such as the PHQ-9 and GAD-7, you may be able to report one unit for each questionnaire completed. For further information, please contact your local payer.

Another note: The PSS (Perceived Stress Scale) is a multipurpose instrument for objectively determining severity of perceived stress symptoms, while also allowing for the monitoring of symptom changes and effects of treatment over time. It is not, however, a diagnostic tool. Results from the PSS must be used in conjunction with clinical judgment and other data as required to reach the appropriate conclusion. For details, visit here.

Need more computerized mental health questionnaires or screeners?

If there are any questionnaires you are administering manually today that you would like to have available within the CBS Health digital platform instead—or if you have other feedback or comments for the CBS team—please let us know by commenting on this blog post or contacting us directly by email. We are always happy to hear from you.

Thanks, as always,

— The Cambridge Brain Sciences Team