Dysfunctional cognitions in hospitalized patients with psychotic versus nonpsychotic major depression

Comprehensive Psychiatry 48 (2007) 357 – 365 www.elsevier.com/locate/comppsych

Dysfunctional cognitions in hospitalized patients with psychotic versus nonpsychotic major depression Brandon A. Gaudianoa,b,4, Ivan W. Millera,b a

Department of Psychiatry and Human Behavior, Brown Medical School, Providence, Rhode Island 02906, USA b Psychosocial Research Program, Butler Hospital, Providence, Rhode Island 02906, USA

Abstract Previous research suggests that psychotic major depression (PMD) is associated with greater illness severity and functional impairment as well as poorer treatment response to antidepressants and psychotherapies compared with nonpsychotic major depression. Although patients with PMD exhibit a number of neurobiological abnormalities, little research has been conducted to date on possible psychological factors that are related to illness in this depression subtype. In the current study, baseline data were pooled from 2 clinical trials in which depressed patients (n = 235) were recruited during a psychiatric hospitalization for an acute episode. Twelve percent (n = 28) of this treatment-seeking sample met criteria for PMD and showed elevated levels of depression severity and dysfunctional beliefs compared with individuals with nonpsychotic major depression. However, even after controlling for depression severity and other relevant baseline variables, only a measure of common dysfunctional beliefs differentiated those with vs those without psychotic features. Furthermore, higher levels of depressive cognitions were related to poorer psychosocial functioning and suicidality in PMD patients. Results suggest that elevated levels of common negative cognitions in depressed patients may be associated with the presence of more severe psychotic symptoms. Adapted cognitivebehavioral treatments may be useful for treating patients with PMD specifically. D 2007 Elsevier Inc. All rights reserved.

1. Introduction Psychotic features are estimated to be present in approximately 12% to 14% [1,2] of depressed patients in the community and in up to 25% [3] of depressed hospitalized samples. Although the psychotic subtype of major depression (PMD) goes underdiagnosed and undertreated in routine practice settings [4,5], previous research suggests that these patients have a more severe and chronic form of illness compared with those with nonpsychotic major depression (NMD) [5-7]. For example, patients with PMD tend to have greater illness severity [8] and suicidality [9], a poorer response to antidepressants [10] and psychotherapy [11], a longer time to remission [7], a greater likelihood of relapse [12], and more frequent hospitalizations [1]. One recent study found that mortality rates in PMD were more than twice those of NMD 15 years after hospitalization [13]. Supported in part by National Institutes of Health grants MH35945, RR05817, MH44778, and MH58866. 4 Corresponding author. Psychosocial Research Program, Butler Hospital, Providence 02906, Rhode Island. E-mail address: [email protected] (B.A. Gaudiano). 0010-440X/$ – see front matter D 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.comppsych.2007.03.003

Psychotic major depression can be differentiated from NMD based on a number of neurobiological abnormalities in areas such as brain structure, hypothalamic-pituitaryadrenocortical axis activity, dopamine and serotonin neurotransmission, and neuropsychological functioning (eg, motor skills, attention, concentration) [6,14]. Previous research also has shown that psychosocial functioning in PMD is typically poorer than that in NMD. For example, Coryell et al [7] assessed the long-term course of illness in a large sample of depressed patients (n = 787) and found that those with PMD had more psychosocial impairment compared with individuals with NMD at 5- and 10-year follow-up. Recently, Goldberg and Harrow [15] reported that functional impairment in patients with PMD contributed to poorer perceived quality of life. However, specific factors related to the poorer functioning in individuals with PMD remain unclear. Considerably less attention has been directed toward understanding potentially relevant psychological factors (in contrast to neurobiological abnormalities) associated with PMD. Although research has confirmed that depressively biased cognitive style; dysfunctional beliefs about the self, others, and the world; and feelings of hopelessness about the

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future play an important role in the development and maintenance of NMD [16-18], relatively little is known about these factors in relation to illness severity and psychosocial functioning in PMD. In fact, we are unaware of any previously published reports systematically examining the role of common depressive cognitions (ie, dysfunctional beliefs, distorted cognitions, cognitive biases) in PMD patients specifically. Furthermore, some argue that psychotic symptoms can be better understood using a bquasi-dimensionalQ model in contrast to the traditional categorical one [19]. This conceptualization of psychosis is based on a growing body of research indicating that schizotypal personality traits and psychotic-like experiences are frequently reported in nonclinical populations. For example, Verdoux et al [20] surveyed 790 primary care patients and found that 10% of individuals without a psychiatric history endorsed persecutory ideation and 15% reported auditory hallucinations. In the National Comorbidity Survey, 28% of subjects endorsed at least one psychotic symptom question [21]. Such findings have led Verdoux and van Os [22] to conclude that bdelusional and hallucinatory experiences are rather frequent in subjects from the general population, and that a symptomatic continuum may exist between dnormalT subjects, those with a mood disorder, and subjects with psychotic disorderQ (p 61). The notion of a bcontinuumQ of psychosis may be particularly relevant to patients with mood disorders, whose symptoms can span the severity spectrum from common dysfunctional thoughts and negative attributions to strongly held delusional beliefs that can be indistinguishable from patients with primary psychotic disorders. In the current study, we pooled data from 2 treatment trials that included depressed patients with or without psychotic features who were recruited during a psychiatric hospitalization. As psychosis is often more subtle in PMD compared with primary psychotic disorders [4,5], we hypothesized that measures of common dysfunctional cognitions also would be elevated in patients with PMD compared with NMD. Such a finding would be consistent with the notion of a continuum of psychotic experiences, as PMD patients would be expected to have higher levels of common dysfunctional thoughts associated with depression in addition to threshold psychotic symptoms. Furthermore, we hypothesized that higher levels of dysfunctional cognitions would be associated with increased illness severity, suicidality, and impaired psychosocial functioning in patients with PMD. Finally, one frequent problem with past research comparing patients with NMD vs PMD has been the failure to adequately account for the potentially confounding influence of illness severity. As all patients in the current study were acutely ill and experiencing similarly elevated levels of illness severity, we hypothesized that measures of common dysfunctional cognitions would better differentiate patients with psychotic vs nonpsychotic depression than other clinical variables.

2. Method 2.1. Participants Baseline data were pooled from 2 clinical trials with similar methodologies investigating combined treatment with medication and psychotherapy for patients with major depression (n = 235). The recruitment periods for studies 1 [23] and 2 [24] were 1981-1986 and 1990-1996, respectively. Inclusion criteria were similar across studies: recruitment during hospitalization, primary diagnosis of major depression (with or without psychotic features) based on structured clinical interview, English speaking, and older than 18 years. Exclusion criteria included the following: significant cognitive impairment; diagnoses of bipolar disorder, alcohol/drug dependence (abuse permitted if clearly secondary), somatization disorder, severe borderline personality disorder, antisocial personality disorder, organic mental disorder, or a primary psychotic disorder (eg, schizophrenia, schizoaffective disorder); current electroconvulsive treatment; or a medical condition that would contraindicate the use of antidepressants. Patients in study 2 also had to live with at least one family member willing to participate in the study because of the inclusion of family therapy in some study arms. The combined sample used in the current study was 76% female; most were white (93%), and the average age was 37 years (range = 18-71, SD = 12). A total of 69% were married or cohabitating, with the remaining single, divorced, or widowed. Education level in the current sample was as follows: 25% did not complete high school, 27% completed high school, and 48% completed at least some college. 2.2. Measures 2.2.1. Modified Hamilton Rating Scale for Depression The 17-item version of the Modified Hamilton Rating Scale for Depression (MHRSD) was used to assess depression severity [25]. The MHRSD is an adapted form of the original Hamilton Rating Scale for Depression [26] that includes standardized question prompts to increase reliability. The MHRSD has good interrater reliability and convergent validity in administrations by paraprofessionals [25]. 2.2.2. Beck Depression Inventory The Beck Depression Inventory (BDI) is a 21-item selfreport instrument that assesses symptoms of depression [27]. The BDI is widely used, and numerous studies have demonstrated its reliability and validity in clinical and nonclinical samples [28]. 2.2.3. Modified Scale for Suicidal Ideation Suicidality was assessed using the Modified Scale for Suicidal Ideation (MSSI) [29], which is an adapted version of the original Scale for Suicide Ideation [30]. The MSSI is an 18-item structured interview that assesses severity of suicidal ideation, intent, competence to attempt suicide, and

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amount of talking/writing about death. Each question is rated on a 4-point scale, and responses are summed to derive a total score. Time frame assessed was the worst 48-hour period during the week before hospitalization. Research has shown that the scale possesses good interrater reliability and high convergent validity [29,30]. 2.2.4. Hopelessness Scale The Hopelessness Scale (HS) is a 20-item self-report measure in which participants respond to true or false questions pertaining to negative expectations about the future [31]. The HS has high internal reliability and validity for discriminating between patients with high vs low suicidal intent [32,33]. 2.2.5. Social Adjustment Scale The Social Adjustment Scale (SAS) is a 54-item selfreport measure that was used to assess psychosocial functioning over the past 2 weeks [34]. Questions pertain to the following domains of functioning: work/school, social and leisure activities, finances, and relationships with family members, romantic partners, and one’s children. Each item is scored on a 5-point scale, with higher scores indicating poorer functioning. An overall score is calculated by averaging all applicable items rated by respondents. The SAS has evidence of good reliability and validity [35,36] and has been used in psychotic mood disorder samples [37]. 2.2.6. Dysfunctional Attitude Scale The Dysfunctional Attitude Scale (DAS) [38] was administered to assess dysfunctional beliefs. The DAS Form A is composed of 40 self-evaluative statements rated on a 7-point Likert scale (totally disagree to totally agree). Dysfunctional beliefs assessed by the DAS include need for approval, perfectionism, need to please others, need to impress, avoidance of appearing weak, control over emotions, and dependence [39]. Research suggests that the DAS has high internal consistency and good test-retest reliability [40]. In addition, the DAS has been shown to discriminate patients with clinical depression [41]. 2.2.7. Cognitive Bias Questionnaire The Cognitive Bias Questionnaire (CBQ) [42] was used to assess negatively biased self-referent cognitive style. Six anecdotes describe situations in which the outcome is either negative or ambiguous. Participants are asked to choose from 4 options based on how they believe they would respond to each event described. Options represent depressed-distorted, nondepressed-distorted, depressed-nondistorted, and nondepressed-nondistorted cognitive styles. The depressed-distorted subscale, which is the sum of items endorsed in this category, was used to assess depressive cognitive biases in the current study. For example, vignette 4 describes the situation of a young man who is alone in his apartment on a Friday night and overhears people discussing their plans to go out for the evening. Question 2 asks

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respondents to choose the response to complete this statement: bBeing alone on a Friday night. . .Q The depressed-distorted response is b. . .upsets me and makes me start to imagine endless days and nights by myself.Q Previous research on the CBQ has demonstrated that the scale possesses good reliability and validity [43,44]. 2.3. Procedure Informed consent was obtained according to procedures approved by the local institutional review board. Baseline assessments were collected during hospitalization before beginning study treatments but after admission to the hospital. Diagnoses were based on the Diagnostic Interview Schedule [45] for study 1 and the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders (DSM), Revised Third Edition [46] for study 2, which were administered by trained, independent assessors. The Diagnostic Interview Schedule was based on diagnostic criteria consistent with the DSM, Third Edition [47], whereas the version of the Structured Clinical Interview for DSM used was based on the DSM, Revised Third Edition criteria [48]. However, both versions of the DSM defined psychotic features in the context of a major depressive episode using the same criteria. Furthermore, these criteria have not changed in the most recent version of the DSM, Fourth Edition, Text Revision [49]. Therefore, we believe that although different diagnostic assessments were used in the studies, diagnoses of PMD were comparable. Assessors achieved interrater agreement of .93 for MHRSD ratings in study 1. Furthermore, raters in study 2 were trained to interrater reliability N.80 on all assessments, with periodic checks performed to protect against rater drift. In study 1, hospitalized (inpatient) individuals were randomly assigned to pharmacotherapy alone, pharmacotherapy plus cognitive therapy, or pharmacotherapy plus social skills training [50,51]. In study 2, hospitalized (inpatient or day hospital) individuals were randomly assigned to pharmacotherapy alone, pharmacotherapy plus cognitive therapy, pharmacotherapy plus family therapy, or all 3 treatments combined [52]. Hospital treatment as usual consisted of medical examination/testing, pharmacotherapy (including the use of antidepressants, antipsychotics, and other medications as appropriate), daily meetings with a psychiatrist, therapy groups, occupational/activities therapy, social work evaluation, and other typical hospital activities. As only baseline measures obtained before starting randomized treatment were used in the current analyses, please refer to the primary reports for full descriptions of the treatments and outcome results. 2.4. Statistical analyses Given the paucity of research on the role of depressive cognitions in PMD, the study was considered exploratory and a was set at P b .05 with 2-tailed tests. Baseline group differences were examined using independent-samples t tests or v 2 tests as appropriate to identify possible covariates to

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include in subsequent analyses. Effect sizes were calculated for significant group differences based on the Cohen [53] d statistic, with a small effect being 0.2, a medium effect being 0.5, and a large effect being 0.8. Pearson r correlations and follow-up hierarchical multiple regression analyses were computed to examine relationships among dysfunctional cognitions and illness severity variables. Additional analyses were conducted to identify which baseline variables were most associated with diagnostic status. Logistic regression based on a forward selection method was used to test variables for possible inclusion in the model [54]. Each dependent variable was tested as a predictor, and the first variable with the smallest likelihood ratio was entered into the model. Other variables were added to the model if their likelihood ratios account for more variance than those already present. After procedures outlined by Hill [55], randomly missing data (6%) were imputed using the expectation maximization (EM) algorithm because it has been shown to be superior to other imputation methods (eg, mean replacement, simple regression). In brief, EM imputes missing values based on maximum likelihood estimates using known participant variables in an iterative process that preserves variability [56]. The EM procedure assumes that the data are missing at random. The Little [57] v 2 test was computed to test for potential patterns of nonrandomness in missing data. However, the Little test was not significant for the EM matrices of imputed variables ( P N .20), suggesting that this assumption was met.

3. Results 3.1. Preliminary analyses Preliminary analyses were conducted between the groups to identify possible covariates to include in subsequent analyses. A total of 28 patients met the criteria for PMD, with the remaining patients (n = 207) meeting the criteria for NMD. The percentages of PMD patients in studies 1 and 2 were similar (11% and 12%, respectively). Baseline data from the Symptom Checklist 90 [58] were available for patients in study 1. As expected, a t test revealed that the PMD group had higher scores on the psychoticism subscale compared with the NMD group (t = 2.41, df = 85, P b .05). The psychoticism scores of the NMD group (mean = 1.3, SD = 0.7) were similar to those reported in a previously published inpatient sample [59] (mean = 1.1, SD = 0.9), but scores of the PMD group were clearly elevated (mean = 1.8, SD = 0.9). The Symptom Checklist 90 data were not available for patients in study 2. However, 93% of study 2 patients with PMD were diagnosed with mood-congruent psychotic symptoms (1 patient had mood-incongruent psychotic symptoms). Sixty-four percent of study 2 PMD patients reported delusions, 79% reported hallucinations, and 43% reported both types of psychotic symptoms. These patients most

frequently reported paranoid delusions (43%) and auditory hallucinations (79%). Table 1 shows the descriptive statistics and group differences on demographic and baseline severity measures between patients with PMD and NMD. The PMD group had significantly higher scores compared with the NMD group on the MHRSD, BDI, and DAS ( Ps b .05). These effect size differences between the groups on the MHRSD (d = .41), BDI (d = .43), and DAS (d = .47) were medium in magnitude. No other significant differences were identified (all Ps N .05). In summary, preliminary results suggested that PMD patients had higher levels of depression severity and dysfunctional attitudes than the NMD patients, but that the groups were similar in terms of their levels of psychosocial impairment, suicidality, hopelessness, and depressed-distorted cognitive biases. 3.2. Zero-order correlations among baseline variables Pearson r correlations were conducted on baseline measures to examine the relationships among dysfunctional cognitions and illness severity variables for the NMD and PMD groups separately. In the NMD subsample (Table 2), dysfunctional attitudes (DAS) were not correlated with the interviewer-rated measure of depression severity (MHRSD), but were significantly correlated with all other measures. Hopelessness (HS) was most strongly correlated with selfreported depression severity (BDI), social functioning (SAS), and dysfunctional attitudes (DAS). Depressivedistorted cognitions (CBQ) were most strongly correlated with dysfunctional attitudes (DAS) and suicidality (MSSI). Relationships among baseline measures were similar in the PMD subsample (Table 3). However, it should be noted that the number of PMD patients was significantly smaller than the number of NMD patients; and thus, significance Table 1 Group comparisons on baseline variables

Female Married Completed high school Anxiety disorder Substance abuse disorder Age MHRSD BDI MSSI HS SAS DAS CBQ

NMD (n = 207)

PMD (n = 28)

Test statistic

% (n) 75 (156) 70 (144) 77 (159)

% (n) 82 (23) 64 (18) 64 (18)

dfs = 1 v 2 = 0.63 v 2 = 0.32 v 2 = 2.08

44 (92) 15 (30)

46 (13) 11 (3)

v 2 = 0.04 v 2 = 0.29

Mean 37.6 23.3 30.9 14.2 13.3 2.7 150.9 2.9

F F F F F F F F F

SD 12.1 4.7 8.8 14.8 5.4 0.4 40.9 2.8

Mean 35.9 25.3 35.0 16.9 14.4 2.8 170.4 3.8

F F F F F F F F F

SD 10.2 4.8 10.5 14.8 5.9 0.7 42.2 3.2

dfs t = t = t = t = t = t = t = t =

= 233 0.47 2.084 2.294 0.91 1.02 1.27 2.414 1.56

Data presented as mean (standard deviation) or percentage (frequency). t test dfs = 233, v 2 dfs = 1. 4 P b .05.

B.A. Gaudiano, I.W. Miller / Comprehensive Psychiatry 48 (2007) 357 – 365 Table 2 Intercorrelations among baseline variables for patients with NMD MHRSD BDI MSSI HS SAS DAS CBQ

MHRSD

BDI

MSSI

HS

SAS

DAS

CBQ

– .434 .224 .244 .244 .11 .234

– .424 .464 .334 .404 .394

– .274 .274 .294 .454

– .394 .374 .264

– .414 .304

– .584

–

n = 207. 4 P b .01.

levels should be interpreted with caution in these analyses. In summary, both the DAS and CBQ were moderately correlated with each other, as well as with suicidality (MSSI) and social functioning (SAS). However, neither the DAS nor the CBQ was correlated with the measures of depression severity (MHRSD and BDI). Hopelessness (HS) was most strongly correlated with self-reported depression severity (BDI). Therefore, results demonstrated that dysfunctional cognitions were associated with important illness domains (eg, suicidality, psychosocial functioning) in patients with NMD and PMD. 3.3. Multiple regression analyses controlling for depression severity The relationships among depressive cognitions and functioning and suicidality may have been partly a function of depression severity. Therefore, follow-up hierarchical multiple regression analyses were conducted controlling for relevant covariates in the PMD group of interest. The MHRSD and BDI were controlled for in independent analyses to examine self-reported vs interviewer-rated severity in the PMD group. The study (1 vs 2) from which the subsamples were drawn also was included as a covariate in these analyses. Covariates were entered in the first step, and depressive cognition measures were entered in the second step. After controlling for the variance attributable to MHRSD and study (1 vs 2), the SAS remained significantly associated with the DAS (t = 2.32, b = .43, P b .05), the CBQ (t = 2.93, b =.50, P b .01), or the HS (t = 2.90, b =.55, P b .01) in PMD patients. Furthermore, associations between the SAS and the DAS or CBQ remained significant

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after substituting the BDI instead of the MHRSD (all Ps b .05). The association between the SAS and HS was only approaching significance after the inclusion of the BDI (t = 1.91, b =.39, P = .69). In addition, even after controlling for MHRSD scores and study, the MSSI was significantly associated with the DAS (t = 2.22, b = .43, P b .05) and CBQ (t = 2.21, b =.41, P b .05) in the PMD group. However, the relationship between the MSSI and HS was no longer significant after controlling for the covariates ( P N .05). Furthermore, relationships between the MSSI and DAS, CBQ, or HS were no longer significant after controlling for the BDI instead of the MHRSD (all Ps N .05). In summary, results suggested that higher levels of dysfunctional cognitions were related to more severely impaired social functioning and increased suicidality in patients with PMD. Furthermore, these relationships were only partially explained by depression severity. 3.4. Logistic regression analysis predicting diagnostic status Logistic regression was used to identify the baseline variables that best differentiated patients with PMD vs NMD. First, an exploratory analysis was conducted using all theoretically relevant demographic and symptom measures. Although t tests showed that only depression severity and dysfunctional attitudes were significantly different between groups, all relevant variables were included in the regression analysis first to examine their relative associations with diagnostic status. The following dependent variables were tested using the forward entry method: sex, age, MHRSD, BDI, MSSI, SAS, DAS, CBQ, and HS. The overall model was significant (v 2 = 5.60, df = 1, P = .018), and the percentage of cases accurately classified was 88%. Results for the final model are shown in Table 4. Only the DAS made a significant contribution in the final model ( P = .019), with higher DAS scores being associated with a diagnosis of PMD. The MHRSD was the only other variable approaching significance ( P = .08). To further examine the association between PMD and DAS scores, we conducted a follow-up hierarchical logistic regression analysis controlling for depression severity. The MHRSD was chosen for entry in the first step because it was the only other variable approaching significance in the

Table 3 Intercorrelations among baseline variables for patients with PMD MHRSD BDI MSSI HS SAS DAS CBQ n = 28. 4 P b .05. 44 P b .01.

MHRSD

BDI

MSSI

HS

SAS

DAS

CBQ

– .424 .01 .23 .09 .13 .09

– .5544 .5544 .374 .35 .36

– .31 .19 .394 .414

– .374 .20 .32

– .474 .5144

– .58

–

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Table 4 Logistic regression results for baseline variables predicting diagnostic status In the model DAS Not in the model MHRSD BDI MSSI HS SAS CBQ Study (1 vs 2) Age Sex Constant

b

SE

Wald v 2

.012

.005

.854

-3.87

P

Expb

CI (95%)

5.52

.02

1.012

1.002-1.022

3.14 1.97 .03 .06 .18 .01 .03 .18 1.13 20.50

.08 .16 .86 .80 .67 .92 .87 .67 .29 .00

.021

n = 235. CI indicates confidence interval.

previous exploratory regression analysis. The DAS was entered in the second step to examine the variance it explained independent of depression severity. The MHRSD was significant in step 1 (Wald v 2 = 4.17, df = 1, P = .041, b =.092, SE =.045, Expb = 1.10). In step 2, the DAS added significantly to the model after accounting for the variance attributable to the MHRSD (Wald v 2 = 4.33, P = .038, b =.010, SE =.005, Expb = 1.01). However, the MHRSD was no longer significant after the DAS was added ( P = .079). Thus, results suggested that the level of dysfunctional attitudes differentiated those with PMD vs NMD, even after controlling for depression severity and other clinical variables. 4. Discussion The results of this exploratory study partially supported our hypotheses regarding the significance of depressive cognitions in PMD. Patients with PMD reported higher levels of common dysfunctional beliefs compared with those with NMD. The effect size difference between the PMD and NMD groups on the DAS was in the medium range. In addition, PMD patients were as expected more severely depressed than those with NMD. However, higher levels of depressive cognitions were associated with greater social impairment and suicidality in PMD patients, in many cases even after controlling for depressive symptoms. Furthermore, we conducted logistic regression analyses to separate the variance associated with depression severity and other relevant baseline variables from depressive cognitions. A measure of common dysfunctional attitudes associated with depression was the only baseline variable that clearly differentiated those with PMD vs NMD. Current findings are consistent with an earlier study by Parker et al [60]. These researchers found that in addition to psychotic symptoms, PMD patients could be distinguished from NMD patients based on severe psychomotor disturbance and the absence of diurnal variation. Furthermore, PMD patients were more likely to exhibit sustained and unvarying depressive thought content (eg, pessimism, sinfulness, low self-esteem). Parker et al concluded that

psychotic features were sufficient but not necessary for diagnosing PMD. They proposed that psychotic symptom bmaskingQ may occur because of symptoms such as psychomotor disturbance and that other clinical features, including the severity of depressive thinking, may be useful for differentiating patients with PMD. In addition, results showing that depressive cognitions were significantly related to social functioning in patients with PMD were consistent with past studies using NMD samples [16-18,61]. This is the first study to our knowledge to confirm this relationship in PMD specifically. However, we did not find a difference in baseline scores between the depressive subtypes in terms of their psychosocial functioning. Several previous studies have reported poorer psychosocial functioning in patients with PMD compared with NMD, particularly when examining patients whose depressive episodes had remitted [37]. It is likely that the lack of differences in overall functioning in the current sample was due to the fact that all patients were hospitalized for an acute depressive episode when the assessments were conducted and thus were experiencing greater overall severity and impairment. In other words, a bceilingQ effect may have occurred. According to published norms, the degree of functional impairment in our sample (mean = 2.8) was somewhat poorer than that reported in other acutely ill depressed samples (mean = 2.5) [35]. Higher levels of common depressive cognitions should not be completely unexpected in depressed patients with psychotic features because they can be understood to exhibit a form of thought disorder. Nevertheless, we believe that the current findings have 2 important implications. First, PMD often goes underdiagnosed and undertreated because clinicians fail to recognize and adequately assess for psychotic symptoms. For example, Rothschild [5] noted that PMD is frequently misdiagnosed as NMD because psychotic symptoms tend to be intermittent, less prominent, or concealed by the patient. Results from the current study suggest that patients with PMD are not only likely to exhibit threshold psychotic symptoms, but also more severely distorted negative cognitions common to depressed individuals in

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general. Furthermore, results suggested that this relationship could not be fully explained by greater severity or other clinical factors. Our findings are also consistent with recent research showing that even slight elevations on the Unusual Thought Content item of the Brief Psychiatric Rating Scale [62] are useful for differentiating between patients with PMD and NMD [63]. The presence of highly distorted beliefs in depressed patients may indicate that a more severe thought disturbance is actually present, signifying the need for a thorough clinical assessment of this domain. Second, results showing that patients with PMD have higher levels of common dysfunctional cognitions may provide a useful insight into the nature of the disorder itself in terms of the sometimes tenuous distinction between dysfunctional beliefs and threshold delusional beliefs. Given the clinical differences often found among depressed patients with or without psychotic features, some researchers have argued that PMD should be considered a unique diagnostic category [5,64]. In other words, it has been suggested that PMD does not merely represent a more severe form of NMD, as it is currently conceptualized in the DSM, Fourth Edition, Text Revision [49]. Although our study does not directly address the nosological distinction between NMD and PMD, results do highlight the notion of a continuum of psychotic symptoms and, in particular, emphasize the quasi-dimensional characteristics of bdelusionalQ beliefs. For example, recent research suggests that subclinical psychotic-like experiences are quite common in nonpsychotic individuals in the general population [19]. Our results support the notion that patients with PMD share many of the typical dysfunctional beliefs found in depressed patients, although individuals with PMD may experience these negative cognitions more frequently or to a more severely distorted degree. Future research is needed to better understand the phenomenology of negative cognitions in psychotic and nonpsychotic forms of depression to identify possible areas of similarities and differences. It also would be useful to investigate whether certain items on the DAS may be particularly helpful for differentiating between the psychotic and nonpsychotic subtypes. Unfortunately, our sample size was not large enough in the current study to adequately pursue these topics. One strength of the current investigation was our use of a depressed sample of hospitalized patients with or without psychotic features who were similar in terms of their severity and impairment. However, there were several limitations to the current investigation that should be considered when interpreting findings. First, there was a higher ratio of women to men and low ethnic/minority representation in our sample. Although this unequal sex distribution is consistent with many depression treatment trials, as well as being reflective of the increased incidence of depression in women in general, the results of the current study may be most generalizable to white depressed women. Second, the rates of PMD found in our sample are not necessarily representative of those in the community or in psychiatric hospital

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settings because participants were being recruited into clinical trials. In fact, it is possible that the prevalence of PMD in our sample underestimates the general rates in hospitalized depressed patients, as participants with psychotic features were not specifically targeted for recruitment in these clinical trials. Unfortunately, data were not available to compare PMD patients with those who refused study participation. Although traditionally PMD has been thought to be more associated with elderly depressed patients, research on this topic has been contradictory [65]. The age of PMD patients in the current study (mean = 36, SD = 10) was younger and similar to that reported in a recent pharmacotherapy trial for PMD (mean = 41, SD = 12) [66]. Third, given the limited number of patients available that met the diagnostic criteria for PMD, the study was only adequately powered to detect medium to large effect size differences; and thus, nonsignificant findings should be interpreted with caution. Given these limitations in our sample characteristics and recruitment procedures, it will be important for future research to attempt to replicate current results using larger, more demographically diverse samples. In addition, the cross-sectional nature of the study design did not allow us to examine the temporal relationships among depression severity, dysfunctional cognitions, and psychosocial functioning. Because of attrition or missing data, there were too few PMD patients available over follow-up to meaningfully examine the current variables of interest longitudinally. Prospective assessment of these variables will be necessary to delineate whether dysfunctional cognitions themselves can lead to increased illness severity and functional impairment or whether they merely represent one aspect of the same clinical phenomenon. Finally, several of the measures used in the study relied on patient self-report; and it would be useful to use interviewerrated or observational measures of depressive cognitive style and functional impairment to assess the reliability of current findings. It should be noted that current results were less consistent when using the BDI to control for depression severity in some analyses, compared with using the MHRSD. One possible explanation for this is that the BDI may have overlapped to a higher degree with the DAS, as it is known to tap into more of the cognitive symptoms of depression [67]. In addition, the BDI is a self-report measure and may have been more influenced by patients’ distorted self-perceptions of severity than the interviewer-rated MHRSD. Furthermore, it is important to note that the DAS was most consistently related to diagnostic status, whereas results using the other 2 measures of dysfunctional cognitions (CBQ and HS) were more equivocal. The psychometric properties of the DAS (eg, greater score ranges) may have made it more useful for detecting group differences and associations with other measures. In conclusion, depressed patients with psychotic features in the current study could be differentiated from those without psychosis based on their higher levels of common dysfunctional attitudes. Furthermore, current findings sug-

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gest that depressive cognitions are associated with clinically relevant illness domains such as psychosocial impairment and suicidality in patients with PMD. Cognitive behavior therapies that target dysfunctional thinking patterns have been shown to be particularly effective for treating nonpsychotic forms of depression [68]. Furthermore, emerging evidence suggests that these strategies also are effective for individuals with primary psychotic disorders when used as an adjunct to pharmacotherapy [69]. Nevertheless, there has been almost no research to date on adapted psychotherapies for patients with PMD specifically [11,70]. Future research should explore whether dysfunctional thinking represents a potentially useful treatment target for psychosocial interventions that can be used as an adjunct to pharmacotherapy in the treatment of PMD. References [1] Johnson J, Horwath E, Weissman M. The validity of major depression with psychotic features based on a community sample. Arch Gen Psychiatry 1991;48:1075 - 81. [2] Ohayon M, Schatzberg A. Prevalence of depressive episodes with psychotic features in the general population. Am J Psychiatry 2002; 159:1855 - 61. [3] Coryell W, Pfohl B, Zimmerman M. The clinical and neuroendocrine features of psychotic depression. J Nerv Ment Dis 1984;172:521 - 8. [4] Smith GN, MacEwan GW, Ancill RJ, Honer WG, Ehmann TS. Diagnostic confusion in treatment-refractory psychotic patients. J Clin Psychiatry 1992;53:197 - 200. [5] Rothschild A. Management of psychotic, treatment-resistant depression. Psychiatr Clin N Am 1996;19:237 - 52. [6] Vega J, Mortimer A, Tyson P. Somatic treatment of psychotic depression: review and recommendations for practice. J Clin Psychopharm 2000;20:504 - 19. [7] Coryell W, Leon A, Winokur G, Endicott J, Keller M, Akiskal H, et al. Importance of psychotic features to long-term course in major depressive disorder. Am J Psychiatry 1996;153:483 - 9. [8] Serretti A, Lattuada E, Cusin C, Gasperini M, Smeraldi E. Clinical and demographic features of psychotic and nonpsychotic depression. Compr Psychiatry 1999;40:358 - 62. [9] Thakur M, Hays J, Kishnan K. Clinical, demographic and social characteristics of psychotic depression. Psychiatry Res 1999;86: 99 - 106. [10] Brown R, Frances A, Kocsis J, Mann J. Psychotic vs. nonpsychotic depression: comparison of treatment response. J Nerv Ment Dis 1982; 170:635 - 7. [11] Gaudiano BA, Beevers CG, Miller IW. Differential response to combined treatment in patients with psychotic versus nonpsychotic major depression. J Nerv Ment Dis 2005;193:625 - 8. [12] Aronson T, Shukla S, Gujavarty K, Hoff A, Dibuono M, Kahn E. Relapse in delusional depression: a retrospective study of the course of treatment. Comp Psychiatry 1988;29:12 - 21. [13] Vythilingam M, Chen J, Bremner JD, Mazure CM, Maciejewski PK, Nelson JC. Psychotic depression and mortality. Am J Psychiatry 2003; 160:574 - 6. [14] Tyrka AR, Price LH, Mello MF, Mello AF, Carpenter LL. Psychotic major depression: a benefit-risk assessment of treatment options. Drug Saf 2006;29:491 - 508. [15] Goldberg JF, Harrow M. Subjective life satisfaction and objective functional outcome in bipolar and unipolar mood disorders: a longitudinal analysis. J Affect Disord 2005;89:79 - 89. [16] Scher CD, Ingram RE, Segal ZV. Cognitive reactivity and vulnerability: empirical evaluation of construct activation and cognitive diatheses in unipolar depression. Clin Psychol Rev 2005;25:487 - 510.

[17] Haaga DA, Dyck MJ, Ernst D. Empirical status of cognitive theory of depression. Psychol Bull 1991;110:215 - 36. [18] Alloy LB, Abramson LY, Whitehouse WG, Hogan ME, Tashman NA, Steinberg DL, et al. Depressogenic cognitive styles: predictive validity, information processing and personality characteristics, and developmental origins. Behav Res Ther 1999;37:503 - 31. [19] Verdoux H, van Os J. Psychotic symptoms in non-clinical populations and the continuum of psychosis. Schizophr Res 2002;54:59 - 65. [20] Verdoux H, Maurice-Tison S, Gay B, Van Os J, Salamon R, Bourgeois ML. A survey of delusional ideation in primary-care patients. Psychol Med 1998;28:127 - 34. [21] Kendler KS, Gallagher TJ, Abelson JM, Kessler RC. Lifetime prevalence, demographic risk factors, and diagnostic validity of nonaffective psychosis as assessed in a US community sample. The National Comorbidity Survey. Arch Gen Psychiatry 1996;53:1022 - 31. [22] Verdoux H, van Os J. Psychotic symptoms in non-clinical populations and the continuum of psychosis. Schizophr Res 2002;54:59 - 65. [23] Miller I, Norman W, Keitner G, Bishop S, Dow M. Cognitivebehavioral treatment of depressed inpatients 1988;19:673 - 95. [24] Miller I, Keitner G, Ryan C, Solomon D, Cardemil E, Beevers C. Treatment matching in the post-hospital care of depressed patients. Am J Psychiatry 2005;162:2131- 8. [25] Miller I, Norman W, Bishop S. The modified Hamilton Rating Scale for Depression. Psychiatry Res 1985;14:131 - 42. [26] Hamilton M. A rating scale for depression. J Neurol Neurosurg Psychiatry 1960;23:56 - 62. [27] Beck A, Ward C, Mendelson M, Mock J, Erbaugh J. An inventory for measuring depression. Arch Gen Psychiatry 1961;4:561 - 71. [28] Beck AT, Steer RA, Garbin RA. Psychometric properties of the Beck Depression Inventory: twenty-five years of evaluation. Clin Psychol Rev 1988;8:77 - 100. [29] Miller I, Bishop S, Norman W, Dow M. The modified Scale for Suicidal Ideation: reliability and validity. J Consult Clin Psychol 1986; 54:724 - 5. [30] Beck AT, Kovacs M, Weissman A. Assessment of suicidal intention: the Scale for Suicide Ideation. J Consult Clin Psychol 1979;47:343 - 52. [31] Beck AT, Weissman A, Lester D, Trexler L. The measurement of pessimism: the Hopelessness Scale. J Consult Clin Psychol 1974;42: 861 - 5. [32] Kovacs M, Beck AT, Weissman A. Hopelessness: an indicator of suicidal risk. Suicide 1975;5:98 - 103. [33] Beck AT, Kovacs M, Weissman A. Hopelessness and suicidal behavior. An overview. 234:1975;1146 - 9. [34] Weissman MM, Bothwell S. Assessment of social adjustment by patient self-report. Arch Gen Psychiatry 1976;33:1111 - 5. [35] Weissman MM, Prusoff BA, Thompson WD, Harding PS, Myers JK. Social adjustment by self-report in a community sample and in psychiatric outpatients. J Nerv Ment Dis 1978;166:317 - 26. [36] Weissman MM, Olfson M, Gameroff MJ, Feder A, Fuentes M. A comparison of three scales for assessing social functioning in primary care. Am J Psychiatry 2001;158:460 - 6. [37] Serretti A, Lattuada E, Smeraldi E. Outcome of affective psychosis. Depress Anxiety 1999;10:50 - 4. [38] Weissman A, Beck A. Development and validation of the Dysfunctional Attitudes Scale. Annual Conference of the Association for Advancement of Behavior Therapy, Chicago; 1978. [39] Beck AA, Brown G, Steer RA, Weissman AN. Factor analysis of the Dysfunctional Attitude Scale in a clinical population. Psychol Assess 1991;3:478 - 83. [40] Oliver JM, Baumgart EP. The Dysfunctional Attitude Scale: psychometric properties and relation to depression in an unselected adult population. Cogn Ther Res 1985;9:161 - 7. [41] Nelson LD, Stern SL, Cicchetti DV. The Dysfunctional Attitude Scale: how well can it measure depressive thinking? J Psychopathol Behav Assess 1992;14:217 - 23. [42] Krantz S, Hammen C. Assessment of cognitive bias in depression. J Abnorm Psychol 1979;88:611 - 9.

B.A. Gaudiano, I.W. Miller / Comprehensive Psychiatry 48 (2007) 357 – 365 [43] Miller IW, Norman WH. Persistence of depressive cognitions within a subgroup of depressed inpatients. Cogn Ther Res 1986; 10:211 - 24. [44] Norman WH, Miller IW, Klee SH. Assessment of cognitive distortion in a clinically depressed population. Cog Ther Res 1983;7:133 - 40. [45] Robins L, Helzer JE, Croughan J, Ratcliff KS. National Institute of Mental Health diagnostic interview schedule. Arch Gen Psychiatry 1981;38:381 - 9. [46] Spitzer R, Williams J, Gibbon M, First M. Structured clinical interview for DSM-III-R, patient edition. Washington, DC7 American Psychiatric Press; 1990. [47] APA. Diagnostic and statistical manual of mental disorders, third edition. Washington, DC7 American Psychiatric Association; 1980. [48] APA. Diagnostic and statistical manual of mental disorder, third edition, revised. Washington, DC7 American Psychiatric Association; 1987. [49] APA. Diagnostic and statistical manual of mental disorder, fourth edition, text revision. Washington, DC7 American Psychiatric Association; 2004. [50] Miller I, Norman W, Keitner G. Cognitive-behavioral treatment of depressed inpatients: six- and twelve-month follow-up. Am J Psychiatry 1989;146:1274 - 9. [51] Miller IW, Norman WH, Keitner GI, Bishop SB, Dow MG. Cognitive-behavioral treatment of depressed inpatients. Behav Ther 1988;19:673 - 95. [52] Miller I, Keitner G, Ryan C, Solomon D, Cardemil E, Beevers C. Treatment matching in the post-hospital care of depressed patients. Am J Psychiatry 2005;162:2131 - 8. [53] Cohen J. Statistical power analysis for the behavioral sciences. Hillsdale, NJ7 Lawrence Erlbaum Associates; 1988. [54] Hosmer DW, Lemeshow S. Applied logistic regression. New York7 Wiley; 1989. [55] Hill M. Missing value analysis in SPSS. Chicago7 SPSS; 1997. [56] Demster A, Laird N, Rubin D. Maximum likelihood from incomplete data via the EM algorithm. J Royal Stat Soc, Series B 1977;39:1 - 38. [57] Little RJA. A test of missing completely at random for multivariate data with missing values. J Am Stat Assoc 1988;83:1198 - 202.

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[58] Derogatis LR, Lipman RS, Covi L. SCL-90: an outpatient psychiatric rating scale—preliminary report. Psychopharmacol Bull 1973;9:13 - 28. [59] Dinning WD, Evans RG. Discriminant and convergent validity of the SCL-90 in psychiatric inpatients. J Pers Assess 1977;41:304 - 10. [60] Parker G, Hadzi-Pavlovic D, Hickie I, Boyce P, Mitchell P, Wilhelm K, et al. Distinguishing psychotic and non-psychotic melancholia. J Affect Disord 1991;22:135 - 48. [61] Zauszniewski JA, Rong JR. Depressive cognitions and psychosocial functioning: a test of Beck’s cognitive theory. Arch Psychiatr Nurs 1999;13:286 - 93. [62] Overall G, Gorham D. The Brief Psychiatric Rating Scale. Psychiatr Rep 1962;10:799 - 812. [63] Keller J, Gomez RG, Kenna HA, Poesner J, DeBattista C, Flores B, et al. Detecting psychotic major depression using psychiatric rating scales. J Psychiatr Res 2006;40:22 - 9. [64] Schatzberg A, Rothschild A. Psychotic (delusional) major depression: should it be included as a distinct syndrome in DSM-IV? Am J Psychiatry 1992;149:733 - 45. [65] Schatzberg AF. New approaches to managing psychotic depression. J Clin Psychiatry 2003;64(Suppl 1):19 - 23. [66] Rothschild AJ, Williamson DJ, Tohen MF, Schatzberg A, Andersen SW, Van Campen LE, et al. A double-blind, randomized study of olanzapine and olanzapine/fluoxetine combination for major depression with psychotic features. J Clin Psychopharmacol 2004;24:365 - 73. [67] Storch EA, Roberti JW, Roth DA. Factor structure, concurrent validity, and internal consistency of the Beck Depression Inventory– Second Edition in a sample of college students. Depress Anxiety 2004;19:187 - 9. [68] Butler AC, Chapman JE, Forman EM, Beck AT. The empirical status of cognitive-behavioral therapy: a review of meta-analyses. Clin Psychol Rev 2006;26:17 - 31. [69] Gaudiano BA. Cognitive behavior therapies for psychotic disorders: current empirical status and future directions. Clin Psychol Sci Pract 2005;12:33 - 50. [70] Gaudiano BA, Miller IW, Herbert JD. The treatment of psychotic major depression: is there a role for adjunctive psychotherapy? Psychother Psychosom [in press].