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A new type of scale for determining remission from depression: The Remission from Depression Questionnaire
Journal of Psychiatric Research 47 (2013) 78e82
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Journal of Psychiatric Research journal homepage: www.elsevier.com/locate/psychires
A new type of scale for determining remission from depression: The Remission from Depression Questionnaire Mark Zimmerman a, b, *, Jennifer H. Martinez a, b, Naureen Attiullah a, b, Michael Friedman a, b, Cristina Toba a, b, Daniela A. Boerescu a, b, Moataz Ragheb a, b a b
Department of Psychiatry and Human Behavior, Brown Medical School, USA Department of Psychiatry, Rhode Island Hospital, Providence, RI, USA
a r t i c l e i n f o
a b s t r a c t
Article history: Received 21 June 2012 Received in revised form 6 September 2012 Accepted 11 September 2012
Current standards for treating major depressive disorder (MDD) recommend that achieving remission should be considered the principal goal of treatment. Recent research suggests that the symptom-based definitions of remission used in efficacy studies do not adequately reflect the perspective of depressed patients receiving treatment in routine clinical settings. We developed the Remission from Depression Questionnaire (RDQ) to capture the broader array of domains considered by patients to be relevant to the construct of remissiondsymptoms of depression, nondepressive symptoms, features of positive mental health, coping ability, functioning, life satisfaction and a general sense of well-being. The current report is the first study of the reliability and validity of the RDQ. The testeretest reliability of the RDQ was studied in 60 depressed outpatients in ongoing treatment. The convergent and discriminant validity of the RDQ was studied in 274 depressed outpatients who were rated on the 17-item Hamilton Depression Scale (HAM-D) and who completed several self-report scales including the Quick Inventory of Depressive Symptomatology (QIDS). The RDQ demonstrated excellent internal consistency, with a Cronbach’s a of .97 for the total scale and above .80 for each of the 7 subscales. The testeretest reliability of the total scale was .85 and above .60 for each subscale. Both the RDQ and QIDS were significantly associated with patients’ self-reported remission status. However, the RDQ remained significantly associated with remission status after controlling for QIDS scores (r ¼ .32, p < .001) whereas the QIDS was not associated with remission status after controlling for RDQ scores (r ¼ .06). The RDQ is a reliable and valid measure that evaluates the multiple domains that depressed patients consider important in determining remission. The results are consistent with prior research suggesting that depressed patients’ perspective of remission goes beyond symptom resolution. Ó 2012 Elsevier Ltd. All rights reserved.
Keywords: Depression Remission
1. Introduction Current standards for treating major depressive disorder (MDD) recommend that achieving remission should be considered the principal goal of treatment (American Psychiatric Association, 2000; Anderson et al., 2000; Stahl, 1999; Thase, 1999). There have been differences in operational definitions of remission, though at their core, these definitions have been primarily symptom-based and therefore narrow in scope. There is little data to suggest that the symptom-based, researcher-developed, definitions of remission used in controlled
* Corresponding author. 146 West River Street, Providence, RI 02904, USA. E-mail address: [email protected] (M. Zimmerman). 0022-3956/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jpsychires.2012.09.006
outcome studies adequately reflect the perspectives of depressed patients receiving treatment in routine clinical settings. A report from our clinical research laboratory suggested that ameliorating or eliminating depression symptoms, while an important goal, is not necessarily the primary outcome that depressed patients wish to achieve from treatment (Zimmerman et al., 2006). The three factors most frequently judged to be very important in determining remission from depression were the presence of features of positive mental health such as optimism and self-confidence, a return to one’s usual, normal self, and a return to usual level of functioning. If current remission definitions do not adequately reflect patients’ perspectives in desired or expected outcome goals, then these definitions are limited. As part of the Rhode Island Methods to Improve Diagnostic Assessment and Services (MIDAS) project, we developed the Remission from Depression Questionnaire (RDQ) to capture
M. Zimmerman et al. / Journal of Psychiatric Research 47 (2013) 78e82
a broader array of domains considered by patients to be relevant to the construct of remission. In the first study of the RDQ we compared its acceptability to the acceptability of the Quick Inventory of Depressive Symptomatology (QIDS) (Rush et al., 2003) in depressed patients in ongoing outpatient treatment (Zimmerman et al., 2011). The QIDS was selected for comparison because it was the self-report depression symptom scale that was one of the primary outcome measures used in the STAR*D study (Trivedi et al., 2006). The patients indicated that the RDQ was a better indicator of their overall state and their goals in treatment, a more accurate and preferred measure to determine the outcome of treatment, and a more valid indicator of remission. The current report from the MIDAS project is the first study of the reliability and validity of the RDQ. In addition to examining the psychometric properties of the scale, we examined the association between the RDQ and the QIDS to 2 definitions of remission. 2. Methods Two studies were conducted. In the first, 100 psychiatric outpatients being treated for DSM-IV MDD in the Rhode Island Hospital Department of Psychiatry outpatient practice were invited to participate in a testeretest reliability study of the RDQ. The first administration was completed in the office after the patients’ appointment. They were given a postage-paid envelope and asked to complete the scale a second time within the next week. In the second study, the convergent and discriminant validity of the RDQ was examined in 274 outpatients receiving ongoing outpatient treatment for MDD. The Rhode Island Hospital outpatient group predominantly treats individuals with medical insurance on a feefor-service basis, and it is distinct from the hospital’s outpatient residency training clinic that predominantly serves lower income, uninsured, and medical assistance patients. For approximately half of the patients the diagnosis of major depression was based on the Structured Clinical Interview for DSM-IV (SCID) (First et al., 1995), whereas the other patients were diagnosed on the basis of an unstructured clinical interview. The sample included 87 (31.8%) men and 187 (68.2%) women who ranged in age from 19 to 80 years (M ¼ 49.0, SD ¼ 13.9). The Rhode Island Hospital institutional review committee approved the research protocols, and all patients provided informed, written consent. In contrast to most measures of depression that assess only symptom presence during the past week or two, the RDQ assesses a broader array of features reported by patients as relevant to determining remission. The domains covered on the RDQ were based on a literature review, our previous study of depressed patients’ ratings of the relative importance of 16 factors in determining remission (Zimmerman et al., 2006), and two focus groups with depressed patients. During the focus groups a list of items was generated and reviewed by patients as to their understandability, redundancy, and relevance to the construct of remission. An initial pool of 77 items was generated, and this was reduced to 41 items after pilot testing. The domains assessed were: symptoms of depression, other symptoms that are often present in depressed patients such as anxiety and irritability, features of positive mental health, coping ability, functioning, life satisfaction, and a general sense of well-being. The items refer to the prior week, and are rated on a 3-point rating scale (not at all or rarely true; sometimes true; often or almost always true). The items are scored 0, 1, and 2 with higher item values reflecting greater pathology. Thus, for symptom items (e.g., “I felt sad or depressed”) a rating of often or almost always true was scored as 2, whereas for the positive mental health items (e.g., “When I woke up I looked forward to the day”) a rating of not at all or rarely true was scored as 2.
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In addition to the RDQ, patients completed the psychosocial impairment and quality of life subscales of the Diagnostic Inventory of Depression (Zimmerman et al., 2004b), the Clinically Useful Anxiety Outcome Scale (Zimmerman et al., 2010), the QIDS, and indicated whether they considered themselves to be in remission at the time of the evaluation. Clinicians rated the patients on the Global Assessment of Functioning (GAF) (American Psychiatric Association, 1994), 17-item Hamilton Depression Scale (HAM-D) (Hamilton, 1960), and the Clinical Global Index of depression severity (CGI-S) (Guy, 1976). Remission was defined in 2 ways: a score of 7 or less on the HAM-D, or a rating of yes to the question about self-perceived remission status. 2.1. Data analyses We undertook a sequence of seven analyses. First, we examined the frequency of items in patients who were in remission. Because the scale is intended as an outcome measure, it is important that items are sufficiently frequent in the target group. We a priori determined that items present in fewer than 25% of remitted patients would be deleted from the scale. Second, we examined the correlation matrix of RDQ subscale scores to determine the amount of shared variance amongst the subscales. Third, we examined two types of reliability of the RDQ total scale and subscalesdtesteretest reliability and internal consistency. Fourth, we examined convergent validity (Campbell and Fiske, 1959) of the RDQ subscales by examining their correlations with the measures of psychosocial functioning, quality of life, anxiety severity, and depression severity. Fifth, we used t-tests to determine whether RDQ subscale scores were significantly higher in patients who were and were not in remission. Remission was defined according to scores on the HAM-D and patients’ self-evaluation of remission status. We used Levene’s test for Equality of Variances to examine homogeneity of variance of the two samples, and when significant used separate variance estimates with adjusted degrees of freedom. Sixth, we compared the association between the RDQ and QIDS and two definitions of remissiondHAM-D 7 and patients’ self-report of remission status. In addition, we computed partial correlations between the RDQ and QIDS with each remission definition while controlling for scores on the other scale. In computing correlations with remission status, remission was assigned a value of 1 and nonremission was coded 0. Thus, correlation coefficients with the QIDS and RDQ had a negative valence. And seventh, we conducted a receiver operating curve analysis to determine the optimal score on the RDQ that maximized agreement with the definitions of remission. We examined the overall and chance-corrected level of agreement in classifying patients as remitted or not between the RDQ and QIDS and the HAM-D and self-report of remission status. On the QIDS remission was defined as a score of 5 and below. 3. Results For the sample of 274 patients, the mean score on the 17-item HAM-D was 8.6 (SD ¼ 6.9), indicating a mild level of depression severity. Consistent with this, the mean score on the CGI-S was 1.8 (SD ¼ 1.2) and QIDS was 9.8 (SD ¼ 5.7). The mean score on the CUXOS was 21.7 (SD ¼ 16.4) indicating a mild level of anxiety severity. The mean score on the GAF was 63.5 (SD ¼ 10.3). 3.1. Elimination of infrequently occurring items We examined the frequency of the 41 items in the patients who were in remission based on the HAM-D ratings. Items that did not occur with at least 25% frequency in patients who were in remission were considered too infrequent to be included on an outcome scale
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M. Zimmerman et al. / Journal of Psychiatric Research 47 (2013) 78e82
assessing remission. No item was present in less than 25% of the remitted patients. We repeated this analysis in the patients who considered themselves to be in remission, and again found that no item was present in less than 25% of the patients. 3.2. Item-scale correlations, internal consistency, and testeretest reliability of the RDQ All item-scale correlations were significant (median ¼ .70). The RDQ demonstrated excellent internal consistency, with Cronbach’s a of .97 for the total scale and above .80 for each of the 7 subscales (Table 1). Of the 100 patients who participated in the testeretest reliability study, 60 completed the RDQ a second time and mailed back the questionnaire within a week after the first completion. There was no difference between completers and noncompleters on age, gender, and RDQ score. The average interval between the test and retest was 4.1 days (SD ¼ 2.0). The data in Table 2 shows that the testeretest reliability of the total scale and the subscales was high. The testeretest reliability of each item was significant (median r ¼ .68). 3.3. Intercorrelation of RDQ subscales and correlation with validity scales The RDQ subscales were significantly intercorrelated (Table 2). The median correlation between the subscales was .70, indicating approximately 50% shared variance. The highest correlations were between the life satisfaction, general sense of well-being and positive mental health subscales. The data in Table 3 shows that each of the RDQ subscales was significantly correlated with measures of depression, anxiety, psychosocial impairment, and quality of life. The RDQ depression symptom scale was most highly correlated with the CGI-S, and the RDQ other symptom scale was most highly correlated with the CUXOS. The RDQ functioning, life satisfaction, and general wellbeing subscales were most highly correlated with the DID quality of life scale. 3.4. Association with remission status Three patients did not indicate whether they considered themselves to be in remission. Of the remaining 271 patients, slightly less than 40% considered themselves to be in remission at the time of the evaluation (38.7%, n ¼ 105). The remitted patients scored significantly lower on each of the RDQ subscales than the patients who did not consider themselves to be in remission (Table 4). QIDS scores were also significantly lower in the remitters than the nonremitters (6.1 4.1 vs. 12.1 5.2, t ¼ 10.7, 257.5 df, p < .001). The QIDS was significantly correlated with self-reported remission status (r ¼ .52, p < .001); however, the partial correlation between the QIDS and self-reported remission status,
Table 1 Testeretest reliability and internal consistency of the RDQ subscales. RDQ subscale
Testeretest reliability
Internal consistency
Depression symptoms Other symptoms Coping ability Positive mental health Functioning Life satisfaction General sense of well-being Total scale
.88 .74 .66 .75 .65 .74 .65 .85
.89 .87 .83 .95 .81 .92 .92 .97
controlling for total RDQ scores, was not significant (r ¼ .06). RDQ total scores were significantly lower in remitters than nonremitters (18.4 16.4 vs. 43.2 17.0, t ¼ 11.8, 268 df, p < .001), and the correlation with remission status was .59 (p < .001). In contrast to the finding for the QIDS, the partial correlation between the RDQ and self-reported remission status, controlling for QIDS scores, was significant (r ¼ .32, p < .001). Based on the receiver operating curve analysis a cutoff score of 27 on the RDQ maximized the sum of sensitivity and specificity. At this cutoff the scale had a sensitivity of 83.7% and specificity of 77.9% in predicting self-reported remission status. The overall level of agreement between the RDQ and self-reported remission status was 81.5% (kappa ¼ .61). In comparison, the overall level of agreement between the QIDS and self-reported remission status was 75.3% (kappa ¼ .45). Slightly more than half of the patients scored 7 and below on the 17-item HAM-D and were therefore considered to be in remission (51.8%, n ¼ 142). The patients who were in remission scored significantly lower on each RDQ subscale than the patients who were not in remission (Table 5). RDQ total scores were significantly lower in remitters than nonremitters (22.1 16.3 vs. 46.0 17.6, t ¼ 11.6, 270 df, p < .001), and the correlation with remission status was .58 (p < .001). The partial correlation between the RDQ and HAM-D remission status, controlling for QIDS scores, was .23 (p < .001). QIDS scores were also significantly lower in remitters than nonremitters (6.8 4.4 vs. 13.0 5.1, t ¼ 10.9, 272 df, p < .001), and the correlation was .55 (p < .001). The partial correlation between the QIDS and HAM-D remission status, controlling for total RDQ score, was significant (r ¼ .17, p < .01). Based on the receiver operating curve analysis, cutoff scores of 27e32 on the RDQ similarly maximized the sum of sensitivity and specificity. At a cutoff of 27, which was the best cutoff when the RDQ was compared to self-described remission status, the scale had a sensitivity of 86.3% and specificity of 64.5% for determining HAM-D remission status. The overall level of agreement between the RDQ and HAM-D remission status was 75.0% (kappa ¼ .50), slightly higher than level of agreement between the QIDS and HAM-D remission status (71.9%; kappa ¼ .45). 4. Discussion Experts agree that remission is the desired outcome when treating depression (American Psychiatric Association, 2000; Anderson et al., 2000; Stahl, 1999; Thase, 1999). In most studies of the treatment of depression, remission is defined as a score below a cutoff value on a symptom severity scale. A previous study from the MIDAS project found that depressed patients consider several factors in addition to symptom resolution as critically important in determining whether a depressive episode was in remission (Zimmerman et al., 2006). In fact, some of these factors such as a return to usual functioning and experiencing features of positive mental health were more frequently rated very important in determining remission from depression than symptom resolution. Consistent with the hypothesis that remission entailed more than the absence of depressive symptoms, in another report from the MIDAS project we found that ratings of symptom severity, functional impairment from depression, and quality of life were each significantly and independently associated with patients’ subjectively perceived remission status (Zimmerman et al., 2008b). These studies suggested the need to develop a new outcome measure that was designed to more broadly evaluate the domains that depressed patients considered important in determining remission. As a first test of this multi-factorial approach towards assessing remission we sought patients’ evaluation of this new scale compared to the QIDS, a widely used self-administered scale
M. Zimmerman et al. / Journal of Psychiatric Research 47 (2013) 78e82
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Table 2 Intercorrelation matrix of RDQ subscales. RDQ subscale
Depression symptoms
Other symptoms
Coping ability
Positive mental health
Functioning
Life satisfaction
Other symptoms Coping ability Positive mental health Functioning Life satisfaction General sense of well-being
.74 .60 .78 .63 .70 .70
.61 .71 .54 .64 .68
.66 .56 .62 .64
.75 .86 .87
.75 .71
.83
All correlations significant at p < .001.
assessing only depressive symptoms (Zimmerman et al., 2011). In the MIDAS project our approach towards developing new scales has consistently included patients’ evaluations of these tools because one of the goals of the MIDAS project has been to develop measures that are feasible to incorporate into clinical practice. The use of standardized scales has not yet been embraced in clinical practice (Gilbody et al., 2002; Zimmerman and McGlinchey, 2008; Zimmerman et al., 2008a). If there is to be a paradigm shift towards measurement based care (Trivedi et al., 2007), it will be important for scales to be as minimally burdensome to patients and disruptive of clinical practice as possible. Consequently, before embarking on a large-scale, expensive, effort towards establishing the reliability and validity of the RDQ, we conducted a comparative study of the scale’s perceived burden and relevance to patients’ goals of treatment. The results of that study indicated that patients considered the multi-factorial RDQ to be a more accurate indicator of their goals of treatment than a purely symptom measure (Zimmerman et al., 2011). The present study is the first of the RDQ’s reliability and validity. We found that the scale had high testeretest reliability and internal consistency. All items were significantly correlated with the total scale. While there were significant correlations between the RDQ subscales, on average they only shared approximately 50% variance, thereby indicating that they were not measuring identical constructs. While both the RDQ and QIDS were significantly associated with both definitions of remission, the RDQ remained significantly associated with both remission definitions after controlling for QIDS scores whereas the QIDS was only associated with the HAM-D remission definition. The RDQ was associated with patients’ self-perceived remission status after controlling for level of depression severity thereby affirming that the RDQ measures constructs other than depressive symptoms that patients consider important in evaluating remission. These results are consistent with our prior studies suggesting that patients’ perspectives of remission go beyond simply symptom resolution. The partial correlation with HAM-D remission status was higher with the RDQ than the QIDS. Perhaps the RDQ accounted for more unique variance in the HAM-D definition of remission than the QIDS because the HAM-D, similar to the RDQ, assesses a broader range of
symptoms including anxiety, irritability and functioning whereas the QIDS only assesses depressive symptoms. The observed disagreement between the two indices of remission, self-reported remission and the HAM-D (Zimmerman et al., in press), raises the question of how to validate a new measure or approach towards assessing remission. The implicit justification for developing the RDQ was the presumed limitation with current definitions such as HAM-D. While the HAM-D is one of the gold standard instruments for evaluating the outcome in treatment studies of depression, problems with the scale have been described (Zimmerman et al., 2005), and the cutoff score typically used to define remission has been questioned (Zimmerman et al., 2004a, 2007). Because of this inherent problem of using a definition of remission that, while valid, has been questioned, we also assessed patients’ perception of remission status. To be sure this, too, is not without potential problems. There is uncertainty in what patients mean when they indicate that they are, or are not, in remission. Nonetheless, patients’ perspective on remission status is an important one to consider because it is likely that this perspective influences requests for, or openness to, modifications in treatment. In the absence of a biological marker indicating that a patient’s depression has resolved it seemed to us appropriate to consider both approaches towards defining remission. A limitation of the study was that it was based in a large, general adult outpatient private practice setting in which patients had health insurance. Replication in samples with other demographic characteristics is warranted. Also, we only compared the RDQ to the HAM-D. A comparison to the MontgomeryeAsberg Depression Rating Scale (Montgomery and Asberg, 1979), the other widely used clinician-administered scale to determine remission, is warranted. Future studies should examine if all constructs assessed by the RDQ are independently associated with remission. At this stage of the scale’s development we considered it premature to examine this issue and eliminate some of the RDQ’s subscales. It would be desirable for the RDQ to be briefer than its current length of 41 items to enhance its feasibility of use. However, we previously found that patients did not consider the RDQ to be more burdensome to complete than the QIDS (Zimmerman et al., 2011). Moreover, the RDQ covers multiple important outcome domains that
Table 3 Correlation between RDQ subscales and measures of depression severity, anxiety, quality of life, and psychosocial functioning. RDQ subscale
Hamilton Depression Scale
Clinical Global Index of Severity
Clinically Useful Anxiety Outcome Scale
Psychosocial functioning
Quality of life
Global Assessment of Functioning
Depression symptoms Other symptoms Coping ability Positive mental health Functioning Life satisfaction General sense of well-being
.62 .55 .45 .61 .47 .53 .58
.70 .60 .49 .62 .56 .54 .59
.69 .77 .56 .65 .50 .58 .64
.68 .57 .50 .64 .57 .62 .62
.69 .58 .48 .66 .58 .64 .65
.61 .53 .44 .57 .53 .52 .55
All correlations significant at p < .001.
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M. Zimmerman et al. / Journal of Psychiatric Research 47 (2013) 78e82
Table 4 RDQ subscale scores in depressed patients who were and were not in remission according to patients’ self-assessment of remission status. RDQ subscale
Remitters (n ¼ 105)
Nonremitters (n ¼ 166)
Mean
SD
Mean
SD
Depression symptoms Other symptoms Coping ability Positive mental health Functioning Life satisfaction General sense of well-being
4.3
4.7
10.6
5.3
10.2**
2.3 2.1 5.5
2.7 1.6 5.4
5.4 3.5 13.1
2.7 1.4 5.6
8.9** 7.9** 10.9**
1.2 1.6 1.5
1.4 1.8 1.8
3.1 3.8 3.8
1.7 1.8 1.9
9.9** 9.9** 9.7**
t Value
**p < .001.
Table 5 RDQ subscale scores in depressed patients who were and were not in remission according to the Hamilton Depression Scale. RDQ subscale
Depression symptoms Other symptoms Coping ability Positive mental health Functioning Life satisfaction General sense of well-being
Remitters (n ¼ 142)
Nonremitters (n ¼ 132)
Mean
SD
Mean
SD
5.1
4.6
11.5
5.4
10.6**
2.8 2.4 6.8
2.6 1.6 5.7
5.7 3.6 13.8
2.8 1.4 5.6
8.9** 6.9** 10.3**
1.6 1.9 1.8
1.6 1.9 1.8
3.2 4.1 4.0
1.8 1.8 1.9
8.2** 9.5** 9.9**
t Value
**p < .001.
would otherwise require several scales to assess. Finally, it will be important to examine the ability of the RDQ to assess change with treatment and predict relapse amongst patients who have responded to treatment. Conflict of interest None.
Contributors Author Zimmerman designed the study and wrote the manuscript. Author Martinez managed and conducted the statistical analyses. Authors Zimmerman, Attiullah, Friedman, Toba, Boerescu, and Ragheb collected the data. All authors contributed to and have approved the final manuscript. Role of the funding source This study was funded by Eli Lilly USA, LLC. The analyses and writing of the manuscript did not receive any input from the funding source.
References American Psychiatric Association. Diagnostic and statistical manual of mental disorders. 4th ed. Washington, D.C.: American Psychiatric Association; 1994. American Psychiatric Association. Practice guideline for the treatment of patients with major depressive disorder (revision); 2000. Washington, DC. Anderson I, Nutt D, Deakin J. Evidence-based guidelines for treating depressive disorders with antidepressants: a revision of the 1993 British Association for Psychopharmacology guidelines. Journal of Psychopharmacology 2000;14:3e20. Campbell DT, Fiske DW. Convergent and discriminant validation by the multitrait multi-method matrix. Psychological Bulletin 1959;56:81e105. First MB, Spitzer RL, Gibbon M, Williams JBW. Structured clinical interview for DSM-IV axis I disorders e patient edition (SCID-I/P, version 2.0). New York: Biometrics Research Department, New York State Psychiatric Institute; 1995. Gilbody SM, House A, O.Sheldon TA. Psychiatrists in the UK do not use outcomes measures. National survey. British Journal of Psychiatry 2002;180:101e3. Guy W. ECDEU assessment manual for psychopharmacology. Rockville, MD: National Institute of Mental Health; 1976. Hamilton M. A rating scale for depression. Journal of Neurology, Neurosurgery, and Psychiatry 1960;23:56e62. Montgomery SA, Asberg M. A new depression scale designed to be sensitive to change. British Journal of Psychiatry 1979;134:382e9. Rush A, Trivedi M, Ibrahim H, Carmody T, Arnow B, Klein D, et al. The 16-item quick inventory of depressive symptomatology (QIDS), clinician rating (QIDS-C), and self-report (QIDS-SR): a psychometric evaluation in patients with chronic major depression. Biological Psychiatry 2003;54:573e83. Stahl S. Why settle for silver, when you can go for gold? Response vs. recovery as the goal of antidepressant therapy. Journal of Clinical Psychiatry 1999;60:213e4. Thase ME. Defining remission in patients treated with antidepressants. Journal of Clinical Psychiatry 1999;60(3e6):35e6. Trivedi M, Rush A, Wisniewski S, Nierenberg A, Warden D, Ritz L, et al. Evaluation of outcomes with citalopram for depression using measurement-based care in STAR*D implications for clinical practice. American Journal of Psychiatry 2006; 163:28e40. Trivedi MH, Rush AJ, Gaynes BN, Stewart JW, Wisniewski SR, Warden D, et al. Maximizing the adequacy of medication treatment in controlled trials and clinical practice: STAR*D measurement-based care. Neuropsychopharmacology 2007;32:2479e89. Zimmerman M, Chelminski I, Posternak M. A review of studies of the Hamilton Depression Rating scale in healthy controls: implications for the definition of remission in treatment studies of depression. Journal of Nervous and Mental Disease 2004a;192:595e601. Zimmerman M, Chelminski I, Young D, Dalrymple KL. A clinically useful anxiety outcome scale. Journal of Clinical Psychiatry 2010;71:534e42. Zimmerman M, Galione J, Attiullah N, Friedman M, Toba C, Boerescu D, et al. Depressed patients perspectives of two measures of outcome: the quick inventory of depressive symptomatology (QIDS) and the remission from depression questionnaire (RDQ). Annals of Clinical Psychiatry 2011;23:208e12. Zimmerman M, Martinez J, Attiullah N, Friedman M, Toba C, Boerescu D, et al. Why do some depressed outpatients who are in remission according to the Hamilton Depression Rating scale not consider themselves to be in remission? Journal of Clinical Psychiatry, in press. Zimmerman M, McGlinchey J, Posternak M, Friedman M, Attiullah N, Boerescu D. How should remission from depression be defined? The depressed patient’s perspective. American Journal of Psychiatry 2006;163:148e50. Zimmerman M, McGlinchey JB. Why don’t psychiatrists use scales to measure outcome when treating depressed patients? Journal of Clinical Psychiatry 2008; 69:1916e9. Zimmerman M, McGlinchey JB, Chelminski I. An inadequate community standard of care: lack of measurement of outcome when treating depression in clinical practice. Primary Psychiatry 2008a;15:67e75. Zimmerman M, McGlinchey JB, Posternak M, Friedman M, Boerescu D, Attiullah N. Remission in depressed patients: more than just symptom resolution. Journal of Psychiatric Research 2008b;42:797e801. Zimmerman M, Posternak M, Chelminski I. Is it time to replace the Hamilton Depression Rating scale as the primary outcome measure in treatment studies of depression? Journal of Clinical Psychopharmacology 2005;25:105e10. Zimmerman M, Posternak MA, Chelminski I. Heterogeneity among depressed outpatients considered to be in remission. Comprehensive Psychiatry 2007;48: 113e7. Zimmerman M, Sheeran T, Young D. The Diagnostic Inventory for Depression: a selfreport scale to diagnose DSM-IV for major depressive disorder. Journal of Clinical Psychology 2004b;60:87e110.
Contents lists available at SciVerse ScienceDirect
Journal of Psychiatric Research journal homepage: www.elsevier.com/locate/psychires
A new type of scale for determining remission from depression: The Remission from Depression Questionnaire Mark Zimmerman a, b, *, Jennifer H. Martinez a, b, Naureen Attiullah a, b, Michael Friedman a, b, Cristina Toba a, b, Daniela A. Boerescu a, b, Moataz Ragheb a, b a b
Department of Psychiatry and Human Behavior, Brown Medical School, USA Department of Psychiatry, Rhode Island Hospital, Providence, RI, USA
a r t i c l e i n f o
a b s t r a c t
Article history: Received 21 June 2012 Received in revised form 6 September 2012 Accepted 11 September 2012
Current standards for treating major depressive disorder (MDD) recommend that achieving remission should be considered the principal goal of treatment. Recent research suggests that the symptom-based definitions of remission used in efficacy studies do not adequately reflect the perspective of depressed patients receiving treatment in routine clinical settings. We developed the Remission from Depression Questionnaire (RDQ) to capture the broader array of domains considered by patients to be relevant to the construct of remissiondsymptoms of depression, nondepressive symptoms, features of positive mental health, coping ability, functioning, life satisfaction and a general sense of well-being. The current report is the first study of the reliability and validity of the RDQ. The testeretest reliability of the RDQ was studied in 60 depressed outpatients in ongoing treatment. The convergent and discriminant validity of the RDQ was studied in 274 depressed outpatients who were rated on the 17-item Hamilton Depression Scale (HAM-D) and who completed several self-report scales including the Quick Inventory of Depressive Symptomatology (QIDS). The RDQ demonstrated excellent internal consistency, with a Cronbach’s a of .97 for the total scale and above .80 for each of the 7 subscales. The testeretest reliability of the total scale was .85 and above .60 for each subscale. Both the RDQ and QIDS were significantly associated with patients’ self-reported remission status. However, the RDQ remained significantly associated with remission status after controlling for QIDS scores (r ¼ .32, p < .001) whereas the QIDS was not associated with remission status after controlling for RDQ scores (r ¼ .06). The RDQ is a reliable and valid measure that evaluates the multiple domains that depressed patients consider important in determining remission. The results are consistent with prior research suggesting that depressed patients’ perspective of remission goes beyond symptom resolution. Ó 2012 Elsevier Ltd. All rights reserved.
Keywords: Depression Remission
1. Introduction Current standards for treating major depressive disorder (MDD) recommend that achieving remission should be considered the principal goal of treatment (American Psychiatric Association, 2000; Anderson et al., 2000; Stahl, 1999; Thase, 1999). There have been differences in operational definitions of remission, though at their core, these definitions have been primarily symptom-based and therefore narrow in scope. There is little data to suggest that the symptom-based, researcher-developed, definitions of remission used in controlled
* Corresponding author. 146 West River Street, Providence, RI 02904, USA. E-mail address: [email protected] (M. Zimmerman). 0022-3956/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jpsychires.2012.09.006
outcome studies adequately reflect the perspectives of depressed patients receiving treatment in routine clinical settings. A report from our clinical research laboratory suggested that ameliorating or eliminating depression symptoms, while an important goal, is not necessarily the primary outcome that depressed patients wish to achieve from treatment (Zimmerman et al., 2006). The three factors most frequently judged to be very important in determining remission from depression were the presence of features of positive mental health such as optimism and self-confidence, a return to one’s usual, normal self, and a return to usual level of functioning. If current remission definitions do not adequately reflect patients’ perspectives in desired or expected outcome goals, then these definitions are limited. As part of the Rhode Island Methods to Improve Diagnostic Assessment and Services (MIDAS) project, we developed the Remission from Depression Questionnaire (RDQ) to capture
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a broader array of domains considered by patients to be relevant to the construct of remission. In the first study of the RDQ we compared its acceptability to the acceptability of the Quick Inventory of Depressive Symptomatology (QIDS) (Rush et al., 2003) in depressed patients in ongoing outpatient treatment (Zimmerman et al., 2011). The QIDS was selected for comparison because it was the self-report depression symptom scale that was one of the primary outcome measures used in the STAR*D study (Trivedi et al., 2006). The patients indicated that the RDQ was a better indicator of their overall state and their goals in treatment, a more accurate and preferred measure to determine the outcome of treatment, and a more valid indicator of remission. The current report from the MIDAS project is the first study of the reliability and validity of the RDQ. In addition to examining the psychometric properties of the scale, we examined the association between the RDQ and the QIDS to 2 definitions of remission. 2. Methods Two studies were conducted. In the first, 100 psychiatric outpatients being treated for DSM-IV MDD in the Rhode Island Hospital Department of Psychiatry outpatient practice were invited to participate in a testeretest reliability study of the RDQ. The first administration was completed in the office after the patients’ appointment. They were given a postage-paid envelope and asked to complete the scale a second time within the next week. In the second study, the convergent and discriminant validity of the RDQ was examined in 274 outpatients receiving ongoing outpatient treatment for MDD. The Rhode Island Hospital outpatient group predominantly treats individuals with medical insurance on a feefor-service basis, and it is distinct from the hospital’s outpatient residency training clinic that predominantly serves lower income, uninsured, and medical assistance patients. For approximately half of the patients the diagnosis of major depression was based on the Structured Clinical Interview for DSM-IV (SCID) (First et al., 1995), whereas the other patients were diagnosed on the basis of an unstructured clinical interview. The sample included 87 (31.8%) men and 187 (68.2%) women who ranged in age from 19 to 80 years (M ¼ 49.0, SD ¼ 13.9). The Rhode Island Hospital institutional review committee approved the research protocols, and all patients provided informed, written consent. In contrast to most measures of depression that assess only symptom presence during the past week or two, the RDQ assesses a broader array of features reported by patients as relevant to determining remission. The domains covered on the RDQ were based on a literature review, our previous study of depressed patients’ ratings of the relative importance of 16 factors in determining remission (Zimmerman et al., 2006), and two focus groups with depressed patients. During the focus groups a list of items was generated and reviewed by patients as to their understandability, redundancy, and relevance to the construct of remission. An initial pool of 77 items was generated, and this was reduced to 41 items after pilot testing. The domains assessed were: symptoms of depression, other symptoms that are often present in depressed patients such as anxiety and irritability, features of positive mental health, coping ability, functioning, life satisfaction, and a general sense of well-being. The items refer to the prior week, and are rated on a 3-point rating scale (not at all or rarely true; sometimes true; often or almost always true). The items are scored 0, 1, and 2 with higher item values reflecting greater pathology. Thus, for symptom items (e.g., “I felt sad or depressed”) a rating of often or almost always true was scored as 2, whereas for the positive mental health items (e.g., “When I woke up I looked forward to the day”) a rating of not at all or rarely true was scored as 2.
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In addition to the RDQ, patients completed the psychosocial impairment and quality of life subscales of the Diagnostic Inventory of Depression (Zimmerman et al., 2004b), the Clinically Useful Anxiety Outcome Scale (Zimmerman et al., 2010), the QIDS, and indicated whether they considered themselves to be in remission at the time of the evaluation. Clinicians rated the patients on the Global Assessment of Functioning (GAF) (American Psychiatric Association, 1994), 17-item Hamilton Depression Scale (HAM-D) (Hamilton, 1960), and the Clinical Global Index of depression severity (CGI-S) (Guy, 1976). Remission was defined in 2 ways: a score of 7 or less on the HAM-D, or a rating of yes to the question about self-perceived remission status. 2.1. Data analyses We undertook a sequence of seven analyses. First, we examined the frequency of items in patients who were in remission. Because the scale is intended as an outcome measure, it is important that items are sufficiently frequent in the target group. We a priori determined that items present in fewer than 25% of remitted patients would be deleted from the scale. Second, we examined the correlation matrix of RDQ subscale scores to determine the amount of shared variance amongst the subscales. Third, we examined two types of reliability of the RDQ total scale and subscalesdtesteretest reliability and internal consistency. Fourth, we examined convergent validity (Campbell and Fiske, 1959) of the RDQ subscales by examining their correlations with the measures of psychosocial functioning, quality of life, anxiety severity, and depression severity. Fifth, we used t-tests to determine whether RDQ subscale scores were significantly higher in patients who were and were not in remission. Remission was defined according to scores on the HAM-D and patients’ self-evaluation of remission status. We used Levene’s test for Equality of Variances to examine homogeneity of variance of the two samples, and when significant used separate variance estimates with adjusted degrees of freedom. Sixth, we compared the association between the RDQ and QIDS and two definitions of remissiondHAM-D 7 and patients’ self-report of remission status. In addition, we computed partial correlations between the RDQ and QIDS with each remission definition while controlling for scores on the other scale. In computing correlations with remission status, remission was assigned a value of 1 and nonremission was coded 0. Thus, correlation coefficients with the QIDS and RDQ had a negative valence. And seventh, we conducted a receiver operating curve analysis to determine the optimal score on the RDQ that maximized agreement with the definitions of remission. We examined the overall and chance-corrected level of agreement in classifying patients as remitted or not between the RDQ and QIDS and the HAM-D and self-report of remission status. On the QIDS remission was defined as a score of 5 and below. 3. Results For the sample of 274 patients, the mean score on the 17-item HAM-D was 8.6 (SD ¼ 6.9), indicating a mild level of depression severity. Consistent with this, the mean score on the CGI-S was 1.8 (SD ¼ 1.2) and QIDS was 9.8 (SD ¼ 5.7). The mean score on the CUXOS was 21.7 (SD ¼ 16.4) indicating a mild level of anxiety severity. The mean score on the GAF was 63.5 (SD ¼ 10.3). 3.1. Elimination of infrequently occurring items We examined the frequency of the 41 items in the patients who were in remission based on the HAM-D ratings. Items that did not occur with at least 25% frequency in patients who were in remission were considered too infrequent to be included on an outcome scale
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assessing remission. No item was present in less than 25% of the remitted patients. We repeated this analysis in the patients who considered themselves to be in remission, and again found that no item was present in less than 25% of the patients. 3.2. Item-scale correlations, internal consistency, and testeretest reliability of the RDQ All item-scale correlations were significant (median ¼ .70). The RDQ demonstrated excellent internal consistency, with Cronbach’s a of .97 for the total scale and above .80 for each of the 7 subscales (Table 1). Of the 100 patients who participated in the testeretest reliability study, 60 completed the RDQ a second time and mailed back the questionnaire within a week after the first completion. There was no difference between completers and noncompleters on age, gender, and RDQ score. The average interval between the test and retest was 4.1 days (SD ¼ 2.0). The data in Table 2 shows that the testeretest reliability of the total scale and the subscales was high. The testeretest reliability of each item was significant (median r ¼ .68). 3.3. Intercorrelation of RDQ subscales and correlation with validity scales The RDQ subscales were significantly intercorrelated (Table 2). The median correlation between the subscales was .70, indicating approximately 50% shared variance. The highest correlations were between the life satisfaction, general sense of well-being and positive mental health subscales. The data in Table 3 shows that each of the RDQ subscales was significantly correlated with measures of depression, anxiety, psychosocial impairment, and quality of life. The RDQ depression symptom scale was most highly correlated with the CGI-S, and the RDQ other symptom scale was most highly correlated with the CUXOS. The RDQ functioning, life satisfaction, and general wellbeing subscales were most highly correlated with the DID quality of life scale. 3.4. Association with remission status Three patients did not indicate whether they considered themselves to be in remission. Of the remaining 271 patients, slightly less than 40% considered themselves to be in remission at the time of the evaluation (38.7%, n ¼ 105). The remitted patients scored significantly lower on each of the RDQ subscales than the patients who did not consider themselves to be in remission (Table 4). QIDS scores were also significantly lower in the remitters than the nonremitters (6.1 4.1 vs. 12.1 5.2, t ¼ 10.7, 257.5 df, p < .001). The QIDS was significantly correlated with self-reported remission status (r ¼ .52, p < .001); however, the partial correlation between the QIDS and self-reported remission status,
Table 1 Testeretest reliability and internal consistency of the RDQ subscales. RDQ subscale
Testeretest reliability
Internal consistency
Depression symptoms Other symptoms Coping ability Positive mental health Functioning Life satisfaction General sense of well-being Total scale
.88 .74 .66 .75 .65 .74 .65 .85
.89 .87 .83 .95 .81 .92 .92 .97
controlling for total RDQ scores, was not significant (r ¼ .06). RDQ total scores were significantly lower in remitters than nonremitters (18.4 16.4 vs. 43.2 17.0, t ¼ 11.8, 268 df, p < .001), and the correlation with remission status was .59 (p < .001). In contrast to the finding for the QIDS, the partial correlation between the RDQ and self-reported remission status, controlling for QIDS scores, was significant (r ¼ .32, p < .001). Based on the receiver operating curve analysis a cutoff score of 27 on the RDQ maximized the sum of sensitivity and specificity. At this cutoff the scale had a sensitivity of 83.7% and specificity of 77.9% in predicting self-reported remission status. The overall level of agreement between the RDQ and self-reported remission status was 81.5% (kappa ¼ .61). In comparison, the overall level of agreement between the QIDS and self-reported remission status was 75.3% (kappa ¼ .45). Slightly more than half of the patients scored 7 and below on the 17-item HAM-D and were therefore considered to be in remission (51.8%, n ¼ 142). The patients who were in remission scored significantly lower on each RDQ subscale than the patients who were not in remission (Table 5). RDQ total scores were significantly lower in remitters than nonremitters (22.1 16.3 vs. 46.0 17.6, t ¼ 11.6, 270 df, p < .001), and the correlation with remission status was .58 (p < .001). The partial correlation between the RDQ and HAM-D remission status, controlling for QIDS scores, was .23 (p < .001). QIDS scores were also significantly lower in remitters than nonremitters (6.8 4.4 vs. 13.0 5.1, t ¼ 10.9, 272 df, p < .001), and the correlation was .55 (p < .001). The partial correlation between the QIDS and HAM-D remission status, controlling for total RDQ score, was significant (r ¼ .17, p < .01). Based on the receiver operating curve analysis, cutoff scores of 27e32 on the RDQ similarly maximized the sum of sensitivity and specificity. At a cutoff of 27, which was the best cutoff when the RDQ was compared to self-described remission status, the scale had a sensitivity of 86.3% and specificity of 64.5% for determining HAM-D remission status. The overall level of agreement between the RDQ and HAM-D remission status was 75.0% (kappa ¼ .50), slightly higher than level of agreement between the QIDS and HAM-D remission status (71.9%; kappa ¼ .45). 4. Discussion Experts agree that remission is the desired outcome when treating depression (American Psychiatric Association, 2000; Anderson et al., 2000; Stahl, 1999; Thase, 1999). In most studies of the treatment of depression, remission is defined as a score below a cutoff value on a symptom severity scale. A previous study from the MIDAS project found that depressed patients consider several factors in addition to symptom resolution as critically important in determining whether a depressive episode was in remission (Zimmerman et al., 2006). In fact, some of these factors such as a return to usual functioning and experiencing features of positive mental health were more frequently rated very important in determining remission from depression than symptom resolution. Consistent with the hypothesis that remission entailed more than the absence of depressive symptoms, in another report from the MIDAS project we found that ratings of symptom severity, functional impairment from depression, and quality of life were each significantly and independently associated with patients’ subjectively perceived remission status (Zimmerman et al., 2008b). These studies suggested the need to develop a new outcome measure that was designed to more broadly evaluate the domains that depressed patients considered important in determining remission. As a first test of this multi-factorial approach towards assessing remission we sought patients’ evaluation of this new scale compared to the QIDS, a widely used self-administered scale
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Table 2 Intercorrelation matrix of RDQ subscales. RDQ subscale
Depression symptoms
Other symptoms
Coping ability
Positive mental health
Functioning
Life satisfaction
Other symptoms Coping ability Positive mental health Functioning Life satisfaction General sense of well-being
.74 .60 .78 .63 .70 .70
.61 .71 .54 .64 .68
.66 .56 .62 .64
.75 .86 .87
.75 .71
.83
All correlations significant at p < .001.
assessing only depressive symptoms (Zimmerman et al., 2011). In the MIDAS project our approach towards developing new scales has consistently included patients’ evaluations of these tools because one of the goals of the MIDAS project has been to develop measures that are feasible to incorporate into clinical practice. The use of standardized scales has not yet been embraced in clinical practice (Gilbody et al., 2002; Zimmerman and McGlinchey, 2008; Zimmerman et al., 2008a). If there is to be a paradigm shift towards measurement based care (Trivedi et al., 2007), it will be important for scales to be as minimally burdensome to patients and disruptive of clinical practice as possible. Consequently, before embarking on a large-scale, expensive, effort towards establishing the reliability and validity of the RDQ, we conducted a comparative study of the scale’s perceived burden and relevance to patients’ goals of treatment. The results of that study indicated that patients considered the multi-factorial RDQ to be a more accurate indicator of their goals of treatment than a purely symptom measure (Zimmerman et al., 2011). The present study is the first of the RDQ’s reliability and validity. We found that the scale had high testeretest reliability and internal consistency. All items were significantly correlated with the total scale. While there were significant correlations between the RDQ subscales, on average they only shared approximately 50% variance, thereby indicating that they were not measuring identical constructs. While both the RDQ and QIDS were significantly associated with both definitions of remission, the RDQ remained significantly associated with both remission definitions after controlling for QIDS scores whereas the QIDS was only associated with the HAM-D remission definition. The RDQ was associated with patients’ self-perceived remission status after controlling for level of depression severity thereby affirming that the RDQ measures constructs other than depressive symptoms that patients consider important in evaluating remission. These results are consistent with our prior studies suggesting that patients’ perspectives of remission go beyond simply symptom resolution. The partial correlation with HAM-D remission status was higher with the RDQ than the QIDS. Perhaps the RDQ accounted for more unique variance in the HAM-D definition of remission than the QIDS because the HAM-D, similar to the RDQ, assesses a broader range of
symptoms including anxiety, irritability and functioning whereas the QIDS only assesses depressive symptoms. The observed disagreement between the two indices of remission, self-reported remission and the HAM-D (Zimmerman et al., in press), raises the question of how to validate a new measure or approach towards assessing remission. The implicit justification for developing the RDQ was the presumed limitation with current definitions such as HAM-D. While the HAM-D is one of the gold standard instruments for evaluating the outcome in treatment studies of depression, problems with the scale have been described (Zimmerman et al., 2005), and the cutoff score typically used to define remission has been questioned (Zimmerman et al., 2004a, 2007). Because of this inherent problem of using a definition of remission that, while valid, has been questioned, we also assessed patients’ perception of remission status. To be sure this, too, is not without potential problems. There is uncertainty in what patients mean when they indicate that they are, or are not, in remission. Nonetheless, patients’ perspective on remission status is an important one to consider because it is likely that this perspective influences requests for, or openness to, modifications in treatment. In the absence of a biological marker indicating that a patient’s depression has resolved it seemed to us appropriate to consider both approaches towards defining remission. A limitation of the study was that it was based in a large, general adult outpatient private practice setting in which patients had health insurance. Replication in samples with other demographic characteristics is warranted. Also, we only compared the RDQ to the HAM-D. A comparison to the MontgomeryeAsberg Depression Rating Scale (Montgomery and Asberg, 1979), the other widely used clinician-administered scale to determine remission, is warranted. Future studies should examine if all constructs assessed by the RDQ are independently associated with remission. At this stage of the scale’s development we considered it premature to examine this issue and eliminate some of the RDQ’s subscales. It would be desirable for the RDQ to be briefer than its current length of 41 items to enhance its feasibility of use. However, we previously found that patients did not consider the RDQ to be more burdensome to complete than the QIDS (Zimmerman et al., 2011). Moreover, the RDQ covers multiple important outcome domains that
Table 3 Correlation between RDQ subscales and measures of depression severity, anxiety, quality of life, and psychosocial functioning. RDQ subscale
Hamilton Depression Scale
Clinical Global Index of Severity
Clinically Useful Anxiety Outcome Scale
Psychosocial functioning
Quality of life
Global Assessment of Functioning
Depression symptoms Other symptoms Coping ability Positive mental health Functioning Life satisfaction General sense of well-being
.62 .55 .45 .61 .47 .53 .58
.70 .60 .49 .62 .56 .54 .59
.69 .77 .56 .65 .50 .58 .64
.68 .57 .50 .64 .57 .62 .62
.69 .58 .48 .66 .58 .64 .65
.61 .53 .44 .57 .53 .52 .55
All correlations significant at p < .001.
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Table 4 RDQ subscale scores in depressed patients who were and were not in remission according to patients’ self-assessment of remission status. RDQ subscale
Remitters (n ¼ 105)
Nonremitters (n ¼ 166)
Mean
SD
Mean
SD
Depression symptoms Other symptoms Coping ability Positive mental health Functioning Life satisfaction General sense of well-being
4.3
4.7
10.6
5.3
10.2**
2.3 2.1 5.5
2.7 1.6 5.4
5.4 3.5 13.1
2.7 1.4 5.6
8.9** 7.9** 10.9**
1.2 1.6 1.5
1.4 1.8 1.8
3.1 3.8 3.8
1.7 1.8 1.9
9.9** 9.9** 9.7**
t Value
**p < .001.
Table 5 RDQ subscale scores in depressed patients who were and were not in remission according to the Hamilton Depression Scale. RDQ subscale
Depression symptoms Other symptoms Coping ability Positive mental health Functioning Life satisfaction General sense of well-being
Remitters (n ¼ 142)
Nonremitters (n ¼ 132)
Mean
SD
Mean
SD
5.1
4.6
11.5
5.4
10.6**
2.8 2.4 6.8
2.6 1.6 5.7
5.7 3.6 13.8
2.8 1.4 5.6
8.9** 6.9** 10.3**
1.6 1.9 1.8
1.6 1.9 1.8
3.2 4.1 4.0
1.8 1.8 1.9
8.2** 9.5** 9.9**
t Value
**p < .001.
would otherwise require several scales to assess. Finally, it will be important to examine the ability of the RDQ to assess change with treatment and predict relapse amongst patients who have responded to treatment. Conflict of interest None.
Contributors Author Zimmerman designed the study and wrote the manuscript. Author Martinez managed and conducted the statistical analyses. Authors Zimmerman, Attiullah, Friedman, Toba, Boerescu, and Ragheb collected the data. All authors contributed to and have approved the final manuscript. Role of the funding source This study was funded by Eli Lilly USA, LLC. The analyses and writing of the manuscript did not receive any input from the funding source.
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