Psychometrics of a brief measure of anxiety to detect severity and impairment: The overall anxiety severity and impairment scale (OASIS)

Abstract

Brief measures of anxiety related severity and impairment that can be used across anxiety disorders and with subsyndromal anxiety are lacking. The Overall Anxiety Severity and Impairment Scale (OASIS) have shown strong psychometric properties with college students and primary care patients. This study examines sensitivity, specificity, and efficiency of an abbreviated version of the OASIS that takes only 2-3 minutes to complete using a non-clinical (college student) sample. 48 participants completed the OASIS and SCID for anxiety disorders, 21 had a diagnosis of ≥1 anxiety disorder, and 4 additional participants had a subthreshold diagnosis. A cut-score of 8 best discriminated those with anxiety disorders from those without, successfully classifying 78% of the sample with 69% sensitivity and 74% specificity. Results from a larger sample (n=171) showed a single factor structure and excellent convergent and divergent validity. The availability of cut-scores for a non-clinical sample furthers the utility of this measure for settings where screening or brief assessment of anxiety is needed.

Psychometric evaluation of the Overall Anxiety Severity And Impairment Scale (OASIS) in individuals seeking outpatient specialty treatment for anxiety-related disorders

“…As in prior studies, the OASIS demonstrated strong psychometric properties, including adequate internal consistency and convergent validity with other measures of emotional distress. Similar to prior studies (Campbell-Sills et al, 2009;Norman et al, 2011), we found support for a unitary factor structure of the OASIS with adequate model fit only when error variance indices of the first two items were allowed to correlate. This result is unsurprising given that these two items are logically contingent on each other; i.e., if anxiety symptoms have not occurred (a frequency rating of 0), severity must also be zero.…”

“…In the initial validation study, Norman and colleagues (2006) found that the OASIS possessed a unitary factor structure and satisfactory test-retest reliability, convergent validity, and divergent validity in a sample of college students. Two subsequent studies examined the properties of the OASIS in primary care patients who were referred to a treatment study for anxiety disorders (Campbell-Sills et al, 2009) and college students (Norman et al, 2011). Consistent with the initial study, both studies found adequate psychometric properties and support for a unitary factor structure; however, the authors further refined the singlefactor model by allowing the error terms of the first two items to be freely estimated.…”

“…and related impairment. To date, all evaluations of the OASIS have occurred in the context of a clinical trial (Campbell-Sills et al, 2009) or other research protocols (Norman et al, 2006(Norman et al, , 2011(Norman et al, , 2013; as such, their external validity is limited by differences between the stringent constraints of the research environment and the realities of private clinical practice. In contrast, the current study utilized a purely naturalistic treatment-seeking clinical sample.…”

“…Campbell-Sills et al (2009) further found that each anxiety disorder and unipolar mood disorder diagnosis contributed unique variance to OASIS scores in primary care patients. Finally, in cut-score analyses, both studies found that a score of eight correctly identified the presence or absence of an anxiety disorder in 87% (Campbell-Sills et al, 2009) and 78% (Norman et al, 2011) of participants, respectively. Extending these results, Norman et al (2013) evaluated the OASIS in a sample of women with and without PTSD symptoms associated with exposure to intimate partner violence (IPV).…”

“…Existing transdiagnostic or general measures of anxiety severity typically assess anxiety symptoms but not functional impairment or behavior change (Campbell-Sills et al, 2009;Norman et al, 2011Norman et al, , 2006. For example, the State-Trait Anxiety Inventory (Spielberger et al, 1983), Beck Anxiety Inventory (Beck and Steer, 1993), Hamilton Anxiety Rating Scale (Hamilton, 1959), and Brief Symptom Inventory-18 Anxiety Subscale (Derogatis, 1993) measure the severity of anxiety symptoms but do not assess anxietyrelated avoidance, restricted activities, or impairment in work or social environments, all of which are critical components of anxiety-related psychopathology (Moses and Barlow, 2006;Telch et al, 1995).…”