Reliability and validity of the Thai version of the Calgary Depression Scale for Schizophrenia

Comparison of unweighted and item response theory-based weighted sum scoring for the Nine-Questions Depression-Rating Scale in the Northern Thai Dialect

Background

The Nine-Questions Depression-Rating Scale (9Q) has been developed as an alternative assessment tool for assessing the severity of depressive symptoms in Thai adults. The traditional unweighted sum scoring approach does not account for differences in the loadings of the items on the actual severity. Therefore, we developed an Item Response Theory (IRT)-based weighted sum scoring approach to provide a scoring method that is more precise than the unweighted sum score.

Methods

Secondary data from a study on the criterion-related validity of the 9Q in the northern Thai dialect was used in this study. All participants were interviewed to obtain demographic data and screened/evaluated for major depressive disorder and the severity of the associated depressive symptoms, followed by diagnosis by a psychiatrist for major depressive disorder. IRT models were used to estimate the discrimination and threshold parameters. Differential item functioning (DIF) of responses to each item between males and females was compared using likelihood-ratio tests. The IRT-based weighed sum scores of the individual items are defined as the linear combination of individual response weighted with the discrimination and threshold parameters divided by the plausible maximum score based on the graded-response model (GRM) for the 9Q score (9Q-GRM) or the nominal-response model (NRM) for categorical combinations of the intensity and frequency of symptoms from the 9Q responses (9QSF-NRM). The performances of the two scoring procedures were compared using relative precision.

Results

Of the 1,355 participants, 1,000 and 355 participants were randomly selected for the developmental and validation group for the IRT-based weighted scoring, respectively. the gender-related DIF were presented for items 2 and 5 for the 9Q-GRM, while most items (except for items 3 and 6) for the 9QSF-NRM, which could be used to separately estimate the parameters between genders. The 9Q-GRM model accounting for DIF had a higher precision (16.7%) than the unweighted sum-score approach.

Discussion

Our findings suggest that weighted sum scoring with the IRT parameters can improve the scoring when using 9Q to measure the severity of the depressive symptoms in Thai adults. Accounting for DIF between the genders resulted in higher precision for IRT-based weighted scoring.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01744-0.

Course and predictors of disability in Thai patients with schizophrenia: A 2-year, multi-center, prospective, observational study

PURPOSE

This 2-year, multi-center, prospective, observational study aimed to describe the course and examine baseline characteristics for predicting disability in Thai patients with schizophrenia.

METHODS

Participants were patients with schizophrenia aged 18-65 years receiving treatment in five tertiary hospitals. Disability was defined by a score of 10 or more of the 12-item World Health Organization Disability Assessment Schedule, version 2.0 (12-item WHODAS 2.0). Other data being collected included socio-demographic data, course of illness, antipsychotics, antipsychotic drug attitudes, behavioral/psychiatric symptoms, alcohol use, social supports, and quality of life at five visits, including weeks 0 (baseline), 24, 48, 72, and 96.

RESULTS

Of the 158 enrolled patients, we analyzed the data of 119 participants who were reassessed at least once during the follow-up. These 119 participants (70% male) had median age and age at psychotic onset of 38 and 22 years, respectively. Disability was found in 43 (36.1%) participants at baseline and 72 (64.7%) participants at week 96. The median [interquartile ranges] WHODAS scores at five time points were 6 [3-12], 9 [4-13], 10 [6-10], 10 [4-10], and 10 [6-10], respectively (p < 0.001). The multivariate logistic regression analysis revealed that duration of psychosis (adjusted odds ratio = 1.08, 95%CI = 1.04 - 1.14, p = 0.001) and depression (adjusted odds ratio = 3.54, 95%CI = 1.14 - 11.06, p = 0.029) at baseline predicted 2-year disability.

CONCLUSIONS

Thai patients with schizophrenia had an increase in disability over a 2-year follow-up period. Duration of psychosis and depression were predictors of disability in these patients.

Reliability of the Calgary depression scale for schizophrenia: A meta-analysis

BACKGROUND

A challenge for clinicians working with individuals diagnosed with schizophrenia is distinguishing depressive symptoms from negative symptoms of schizophrenia. The Calgary Depression Scale for Schizophrenia (CDSS) was developed for this purpose. No review has previously explored its reliability across multiple studies using advanced statistical means.

OBJECTIVES

This meta-analysis aimed to quantify the CDSS' internal consistency, inter-rater reliability (IRR) and test-retest reliability.

METHOD

A systematic literature search was conducted to find articles reporting on the CDSS' reliability. Articles were screened against the inclusion and exclusion criteria, with data extracted from 40 studies. Overall meta-analytic effects were calculated, and for internal consistency and IRR coefficients subsequent analyses explored between-study variation. The small test-retest reliability dataset limited analysis.

FINDINGS

The internal consistency meta-analytic effect was 0.83 (95% CI:0.82-0.84). Higgins I² indicated an acceptable level of variation between studies' alpha estimates. This suggests all items in the CDSS are measuring the same construct (i.e. symptoms of depression). The IRR meta-analytic effect was 0.88 (95% CI:0.86-0.91), with Higgins I² indicating high levels of heterogeneity. This was not deemed problematic variance as it is within levels expected for psychometric measures and, therefore, considered acceptable for this literature. This reflects high level of agreement between different raters when using the CDSS on the same client.

CONCLUSIONS

This review suggests the CDSS has good internal consistency and excellent IRR. Further research will help understand its test-retest reliability.

Exploring the Psychometric Properties and the Factor Structure of the Calgary Depression Scale for Schizophrenia Across the Schizotypy Continuum

This study evaluated the psychometric properties and factor structure of the Calgary Depression Scale for Schizophrenia (CDSS) across different levels of the schizotypy continuum. A combined sample of high-schizotypy, at-risk mental states, and patients with first-episode psychosis was assessed for depression and other clinical and functional outcomes. Additionally, experience sampling methodology was used to assess depressive and psychotic-like experiences in daily life. The CDSS exhibited solid internal consistency, validity, and discrimination between depressed and nondepressed participants. Confirmatory factor analyses and the associations of the resulting factors with clinical and functional measures supported a two-factor structure that included general depression and guilt factors. Furthermore, both factors of the CDSS were differentially related to positive and negative symptoms of psychosis in daily life. The CDSS appears to have two underlying psychopathological dimensions and to be a reliable and valid measure for assessing depression across the schizotypy continuum.

Psychiatric, cognitive functioning and socio-cultural views of menstrual psychosis in Oman: an idiographic approach

BACKGROUND

Most documented cases of menstrual psychosis have been from Euro-American populations with reports from cross-cultural populations being only a few. A primary aim was to determine whether the cyclical/episodic nature of menstrual psychosis among case series observed at a tertiary care unit in Oman fulfills the diagnostic criteria of the International Classification of Diseases (ICD-10) and diverge into Brockington's sub-types (World Psychiatry. 2005;4(1):9-17). Related aims were to solicit measures of psychometric functioning of those with menstrual psychosis and associated idioms of distress.

METHODS

A series of consecutive patients seeking psychiatric consultation from January 2016 to December 2017 were screened via structured interview-Composite-International Diagnostic Interview (CIDI) and Brockington's sub-types. The identified patients (n = 4) also underwent psychometric evaluation including examination of affective functioning, intellectual capacity and neuropsychological functioning (i.e.attention and concentration, learning and remembering, executive function, processing speed and speech and language). The analysis of outcome measures was via an idiographic approach.

RESULTS

The spectrum of distress among people with menstrual psychosis does not fit existing psychiatric nosology. Evaluations revealed that a majority of the participants displayed something akin to morbid phenomena relating to manic and psychotic symptoms. In the parlance of traditional Omani society, this would be termed "spirit possession". In terms of classification by timing within the menstrual cycle as expounded by Brockington, the present case series in Oman fulfilled the definition of catamenial psychosis and paramenstrual psychosis. With regard to psychometric function, all participants performed adequately on indices of intellectual functioning but appeared to have impairments in neuropsychological functioning, including the dimensions of processing speed, episodic memory, and executive functioning. Within the given society, the periodicity of mind alteration has been attributed to spirit possession.

CONCLUSIONS

This is one of the first case series of its kind in the country elucidating whether the manifestation of menstrual psychosis among individuals in Oman fulfills the subtypes postulated by Brockington. The present case series suggests that menstrual psychosis is marked with neuropsychological impairments that were previously observed in other phasic manic episodes or brief psychotic disorders.

Validation of the Arabic Version of Calgary Depression Scale for Schizophrenia

BACKGROUND

Patients with schizophrenia commonly show both depressive and negative symptoms that can differentially affect the prognosis and course of treatment. The Calgary Depression Scale for Schizophrenia (CDSS) was designed to distinguish between depression and negative symptoms in patients with schizophrenia. The purpose of this study is to validate an Arabic version of the CDSS among patients with schizophrenia.

METHODS

The diagnosis of schizophrenia was confirmed using the Arabic Mini International Neuropsychiatric Interview 6 (MINI 6). A standardized translation back-translation process was adopted. One rater administered the Arabic CDSS to subjects with schizophrenia as well as to a control group who should not have any psychiatric disorder except for depression. Another rater, blinded to the results administered the already validated Arabic version of Beck Depression Inventory-II (BDI-II).

RESULTS

We recruited 102 patients and 102 controls subjects. The CDSS showed good internal consistency in the active group (Cronbach's alpha = 0.82). The Intraclass Coefficient correlations (ICC) for the inter-rater reliability (n = 21) was 0.90, p<0.05 and test-retest reliability (n = 19) was 0.85, p<0.001. When compared to the BDI-II, the cutoff score of 5 on the Arabic CDSS showed reasonable sensitivity and specificity of 72.75% and 67.95% respectively.

CONCLUSIONS

The psychometric properties of the Arabic version of CDSS demonstrate that it is a valid tool to assess the depressive symptoms in the Arab patients with schizophrenia.

Augmentation with antidepressants in schizophrenia treatment: benefit or risk

We focused on the application of antidepressants in schizophrenia treatment in this review. Augmentation of antidepressants with antipsychotics is a common clinical practice to treat resistant symptoms in schizophrenia, including depressive symptoms, negative symptoms, comorbid obsessive-compulsive symptoms, and other psychotic manifestations. However, recent systematic review of the clinical effects of antidepressants is lacking. In this review, we have selected and summarized current literature on the use of antidepressants in patients with schizophrenia; the patterns of use and effectiveness, as well as risks and drug-drug interactions of this clinical practice are discussed in detail, with particular emphasis on the treatment of depressive symptoms in schizophrenia.

Predictors of quality of life among individuals with schizophrenia

PURPOSE

The study reported here aimed to evaluate both biological and psychosocial factors as predictors for quality of life as well as to examine the associations between the factors and quality of life in individuals with schizophrenia.

METHODS

Eighty individuals with schizophrenia were recruited to the study. The Thai version of the World Health Organization Quality of Life-BREF was utilized to measure the quality of life. The five Marder subscales of the Positive and Negative Syndrome Scale were applied. Other tools for measurement included the Calgary Depression Scale for Schizophrenia and six social support deficits (SSDs). Pearson/Spearman correlation coefficients and the independent t-test were used for the statistical analysis to determine the associations of variables and the overall quality of life and the four domain scores. A multiple linear regression analysis of the overall quality of life and four domain scores was applied to determine their predictors.

RESULTS

The Positive and Negative Syndrome Scale total score, positive symptoms, negative symptoms, disorganized thought, and anxiety/depression showed a significant correlation with the overall quality of life and most of the four domain scores. Depression, SSDs, and adverse drug events showed a significant correlation with a poorer overall quality of life. The multiple linear regression model revealed that negative symptoms, depression, and seeing a relative less often than once per week were predictors for the overall quality of life (adjusted R (2)=0.472). Negative symptoms were also found to be the main factors predicting a decrease in the four domains of quality of life - physical health, psychological, social relationships, and environment.

CONCLUSION

Negative symptoms, depression, and poor contact with relatives were the foremost predictors of poor quality of life in individuals with schizophrenia. Positive symptoms, negative symptoms, disorganized thought, anxiety/depression, SSDs, and adverse events were also found to be correlated with quality of life.