Reliability and validity of severity dimensions of psychopathology assessed using the Structured Clinical Interview for DSM‐5 (SCID)

Lifetime and current psychopathology were assessed by interviewers using an adapted version of the research version of the SCID (First et al., 2015). Specifically, the following 10 disorders were assessed— major depressive disorder (MDD), alcohol use disorder (AUD), substance use disorder (SUD), post-traumatic stress disorder (PTSD), panic disorder (PD), agoraphobia, social anxiety disorder (SAD), specific phobia, obsessive–compulsive disorder (OCD), and generalized anxiety disorder (GAD; see Supporting Information for results for the anorexia, bulimia, and binge eating disorder modules, which were also administered, but are not reported in the main analyses due to small N). As personal history of psychosis or mania was an exclusion criterion, lifetime psychosis and mania were assessed using the psychotic screening module and manic episode section from the SCID’s Mood Disorders module. The SCID for the present study was identical to the SCID-5, with the following exceptions. First, the instrument used a slightly different structure than the SCID-5. The SCID-5 sometimes assesses life-time diagnostic criteria and then current criteria for some disorder modules, and sometimes does current and then lifetime (only if the current diagnosis was not met). To aid in the symptom severity assessment of psychopathology, each module of the adapted SCID was organized to always assess lifetime symptoms first and then current symptoms. Second, the separate parts of multicomponent symptoms were coded independently (e.g., the MDD symptom “worthlessness or guilt” [Symptom 7] yielded separate ratings for worthlessness and guilt). Third, to increase sensitivity to individuals with subthreshold psychopathology and facilitate the calculation of symptom severity scales, we modified some of the skip-out rules in the SCID. Specifically, interviewers ignored all but the first “skip out” for all disorders except MDD and GAD. For example, for PTSD, if a subject received either a 2 or 3 for Criterion A (exposure to a trauma), interviewers ignored all subsequent “skip outs” and assessed all lifetime PTSD symptoms even if the subject did not fully meet criteria B, C, D, and/or E (e.g., they only had one symptom from Criterion D). However, if a subject received a “1” for Criterion A for PTSD (i.e., they never experienced a trauma), the rest of the PTSD symptoms were not assessed as it would not make sense to assess a person’s reactions to a trauma if they never experienced a trauma. Using PD as another example, it would not make sense to assess whether a person worried about additional attacks (Criterion B) if they never had a panic attack (Criterion A). Interviewers also ignored the first “skip out” at the beginning of the MDD and GAD sections because MDD and GAD contain symptoms whose presence are not dependent on the cardinal symptom(s). For example, all of the symptoms of MDD were assessed even if the cardinal symptoms (depressed mood and anhedonia) were not present. Fourth, additional items related to previous course of illness (e.g., duration of longest episode and time since last symptomatic) were also added to each module (data not included in this report). Fifth, the time frames for current psychopathology were modified for some disorders. Rather than assessing current agoraphobia, SAD, and specific phobia using the past 6 months and assessing current AUD and SUD using the past 12 months (as specified in the SCID-5), we elected to use the past 1 month to assess these current disorders. This modification allowed for the assessment of current symptoms using the same time window as our measures of current functioning (e.g., World Health Organization Disability Assessment Schedule [WHODAS], Global Assessment of Functioning [GAF], and Social and Occupational Functioning Assessment Scale [SOFAS]), thus facilitating concurrent validity analyses of current psychopathology. Sixth, although the SCID-5 includes questions assessing functional impairment and perceived distress associated with some disorders, several disorders do not include clinically significant impairment or distress as a criterion and do not have questions assessing functional impairment and distress due to symptoms of the specific disorder. Therefore, prompts and rating scales from the ADIS-IV (Brown et al., 1994) were added for each disorder, and for both lifetime and current psychopathology. This provided measures of disorder-specific impairment and distress that were consistent across disorders, thereby facilitating analyses of concurrent validity. These ratings consisted of separate assessments of perceived distress and three forms of impairment (social, occupational, and “other” impairment that resulted from the specific psychopathology) made along a 9-point scale ranging from 0 (none) to 8 (severe), with (as per ADIS-IV convention) ratings of 2 or higher signifying clinically significant distress or impairment. To provide measures of overall symptom severity and functioning, the GAF Scale (American Psychiatric Association, 1994) was modified slightly to only focus on overall symptom severity at the time of the interview and the SOFAS (Goldman, Skodol, & Lave, 1992) was used to focus solely on overall functional impairment due to current psychopathology. This is consistent with previous recommendations that the GAF be divided into two scales (Aas, 2010). Interviewers were trained to criterion by viewing the SCID-101 training videos (SCID-101, 1998), observing two or three SCID interviews with an experienced interviewer, and completing three SCID interviews (observed by the first author or an advanced interviewer) in which diagnoses were in full agreement with those of the observer. A subset of participants (n = 51) completed a second SCID with a different interviewer blind to the first interview within 3 weeks of their first SCID (M = 8.51 days, SD = 4.31) to assess the test–retest reliability of symptom dimensions and categorical diagnoses.