The results of this study should be considered in light of several methodological limitations. Our findings are constrained by small sample sizes for five of the nine assessed disorders. Fewer than five cases received CIDI diagnoses of either alcohol abuse/dependenceor drug abuse/dependence and confidence bounds on the kappas for social phobia, dysthymia, and agoraphobia suggested inconclusive results. In addition, not all criteria were assessed by the CIDI, so results may vary if this additional information (e.g. collecting information on bereavement) were collected during assessment. Furthermore, some diagnoses that are part of DSM-IV (e.g. mania, schizoaffective disorders, somatisation disorders) were not assessed in the NLAAS or the clinical reappraisal datasets, and therefore were excluded from these analyses. We did not include somatisation because of lack of consensus on the criteria to assess the disorder.
Notwithstanding, given the recent adaptation of the CIDI for use in the CPES, our study evaluates the concordance of CIDI diagnoses with clinical interviews obtained with the SCID. For Latinos, CIDI-SCID concordance at the aggregate level of disorder is comparable to, although lower than, the other published reports on the CIDI 3.0, as described by Haro et al., 2006
. The lower kappas would be expected due to the fact that the NLAAS clinical reappraisal followed a blinded design and the Haro reported reappraisal studies did not. As can be seen from the results in , 13% of the discordance (25/195 discordant cases) was due to respondents denying during the later SCID interview that they had ever endorsed the CIDI screener probes.
The classificatory accuracy -or caseness established - ranged from 78% for any disorder to 95% for substance use disorders for our Latino sample. For Latinos, the CIDI does very well identifying negative cases and classifying disorders at the aggregate level. Good concordance was also found for major depressive episode and panic disorder. This may be due to the fact that panic is a paroxysmic, discrete event with high valence and that major depressive episode is a familiar condition with symptoms that are easy to comprehend and describe, facilitated by public awareness campaigns about its symptoms (Correll & Linden, 2005
However, our data suggest that the CIDI 3.0 presents problems for assessing PTSD and GAD, and also needs additional testing regarding social phobia, dysthymia and agoraphobia. The lack of overlap between the CIDI and the SCID assessments of PTSD was dramatic, probably due to the different ways of evaluating the presence of the disorder across instruments. The CIDI assesses a long list of specific traumatic events, whereas the SCID asks a general question about trauma exposure. Other potential explanations for the observed lack of concordance relate to characteristics of the illness itself, which includes avoidance as one of its symptoms. PTSD patients might want to try to avoid recounting their symptoms, particularly soon after being asked to remember these events. An even more likely explanation is that exposure (both in terms of severity and chronicity of the exposure) and PTSD characteristics may differ significantly by race and ethnicity (Antai-Otong, 2002
; Elsass, 2001
; Hernandez, 2002
; Hernandez, Gangsei, & Engstrom, 2007
), with clinical assessment being particularly problematic for clients from non-Western backgrounds. Because the evaluation of trauma in the SCID, as opposed to the CIDI, is based on the clinician's own interpretation of the meaning of a particular trauma given the social norms of the patient's culture, it might be particularly challenging for clinicians to assess PTSD in the absence of cultural anchors (Alarcon, 2005). So if the patient says that witnessing domestic violence is typically expected in his/her home country, the clinician might judge that the event was not traumatic for the respondent, while the CIDI structure does not allow the interviewer to assess the impact of the trauma based on how normative is the experience in the respondent's context.
For GAD, our low concordance results are consistent with the literature on previous versions of the CIDI that suggest low levels of sensitivity for detecting GAD (Komiti et al., 2001
). In examining the procedural validity of CIDI diagnoses of GAD, Wittchen (Wittchen, Kessler, Zhao, & Abelson, 1995
) found that GAD diagnoses obtained with the UM-CIDI (a modified version of the CIDI used in the NCS) also showed low levels of agreement with SCID diagnoses (κ = 0.35). Future work is needed to address whether Latino respondents have particular difficulty understanding or endorsing the criterion requiring respondents to identify difficulty controlling their worry as a condition of a GAD diagnosis.
Our results suggest that, for Latinos, loosening the diagnostic criteria for each category by one item might improve CIDI - SCID concordance for depressive disorders and some anxiety disorders (GAD and PTSD). This finding requires further inquiry. It is possible that certain diagnostic criteria do not apply as well to Latinos because they represent a category fallacy (Kleinman, 1987
), whereby concepts used in one culture do not map easily onto another culture. For instance, questions about the duration requirement for major depressive episode (e.g., depressed mood or loss of interest must happen within the same two week period with other symptoms) might not correspond to Latino time concepts about depressive illness leading to inconsistent answers depending on how the questions are asked. Assessing conceptual equivalency for monolingual Spanish speakers, particularly immigrants, may help clarify whether lack of endorsements of probes happens more readily when Latinos do not ascribe to mental health concepts in the same way as set out in DSM-IV. Given the insufficient sample size in our Clinical Reappraisal study, we were unable to evaluate the conceptual equivalence for monolingual Spanish speakers as compared to the monolingual English speakers and respondents that spoke both languages. A more extensive analysis, such as the item response theory analysis, would be required to tease out this potential measurement bias from differences in endorsement rates due to severity of depressive symptoms.
An alternative explanation involves difficulties understanding certain concepts embedded in the questions, possibly due to educational barriers or cultural differences. These include the illness episode concept or the evaluative element embedded in certain questions requiring respondents to conduct a comparative assessment, such as deciding whether the behavior is maladaptive and leads to significant impairment. Because the SCID permits the clinician to return to or revise sections if interviewees disclose information relevant to a previous diagnostic module, further probes could have facilitated revising respondents' answers. Such is not the case in the CIDI, where 23 out of 25 respondents were dropped from the diagnostic battery because they denied one of the probes required to continue into the next part of the diagnostic section.
Loosening the time dimension also appears important particularly for substance use disorders, where concepts of time might be different in Latino culture (Canino et al., 2004
). Simplifying the criteria so as to decrease the salience of time might improve the clinical concordance of the CIDI for Latino respondents. The finding that SCID prevalence rates of substance use disorders are higher than those obtained by the CIDI, might also be due to clinicians' greater ability to elicit stigmatized and illegal behaviors. In addition, the SCID and CIDI assess substance use disorders differently, possibly contributing to the striking discrepancy in prevalence rates obtained by the two instruments. In the CIDI, respondents must meet abuse to be evaluated for dependence, whereas in the SCID, abuse and dependence are evaluated independently (see Grant et al., 1996
Requiring more stringent evaluations of dysfunction/impairment would likely improve the concordance between the CIDI and the SCID for social phobia, alcohol abuse/dependence, and drug abuse/dependence. Our data suggests that “grey” cases, those respondents who were positive to one of the instruments and not the other, would particularly benefit from additional information on dysfunction to help establish their caseness status. The open-endedness of the SCID evaluation probably allowed clinicians to return to previously completed modules during the same evaluation and include the newly obtained material, which could not be done on the CIDI evaluation.
These reasons for discordance described above, combined with the fact that the aggregate disorders have a higher concordance than the individual disorders, suggest that discordance is due to methodological differences, particularly in how these instruments codify “grey” cases. Certain diagnostic criteria seem to pose difficulty for Latino respondents, and should be better operationalized to avoid misclassifications depending on how the questions are asked. Although in both assessments Latino respondents appear to recognize the experience being assessed in either instrument, they either experience the disorder with minor variations (e.g., differing by one criterion) or have difficulty being exact about the time frame in one of the assessments. This variation might be better captured by a dimensional approach to diagnosis currently proposed for DSM-V.
Our results suggest several methodological improvements to diagnostic assessments for Latino respondents. These include expanding screening questions, opening up the time frames for assessment, gathering more information within each diagnostic section prior to skipping out respondents, clarifying the threshold for severity or dysfunction, and loosening the criteria for certain disorders that appear not to map so readily onto illness expressions typical among Latinos. Populations differ in terms of illness expressions, sense of time, health literacy, and rates of formal education. This variation could affect how they answer questions on structured and semi-structured instruments. A goal of epidemiology is to assess variations in psychopathology across population subgroups, which requires that enough information be obtained on each disorder to evaluate its variation. One of the major problems faced by the field stems from limitations of current instruments (e.g., skip patterns, limited symptom inclusion) which do not permit an easy comparison of alternative illness expressions across groups. The proposed improvements should be tested in future studies to evaluate their impact on concordance. Improved concordance between diagnostic assessments will aid in the interpretation of DSM-IV prevalence estimates generated by the CIDI and increase the clinical relevance of the CIDI for community epidemiological surveys (Kessler et al., 2004