Somatic symptoms have negligible impact on Patient Health Questionnaire-9 depression scale scores in neurological patients

Exploring Anxiety and Depression Among Medical Undergraduates in South Africa: A Cross-Sectional Survey

Background/Objectives: Globally, there has been an increase in the prevalence of anxiety and depression among university students, and medical students are no exception. Medical students are especially susceptible to these mental health challenges, primarily due to multifaceted stressors, which can significantly impact their academic achievements and future career. There is a pressing need for comprehensive research that not only investigates the prevalence of anxiety and depression among medical students but also explores strategies for developing effective mental health interventions and support systems that can enhance the well-being of medical students. Therefore, this study aimed to identify the prevalence and severity of anxiety and depression among medical students at a university in South Africa, evaluating the association of socio-demographic, student, and clinical variables with total general anxiety disorder (GAD-7) and patient health questionnaire (PHQ-9) scores. Methods: A survey-based quantitative cross-sectional study was conducted with 208 medical undergraduate students at a South African university. Participants who provided written consent completed GAD-7 and PHQ-9 questionnaires together with socio-demographic, student, and clinical variable information. The relationship between socio-demographic, student, and clinical variables and total GAD-7 and PHQ-9 scores was determined using the Mann-Whitney U test and Kruskal-Wallis H test. Correlation analysis was used to establish the relationship between total anxiety and depression scores. The threshold for statistical significance was set at p ≤ 0.05. Results: More than half of the participants were female (n = 130; 62.5%), single (n = 123; 59.1%), and belonged to the Pedi ethnic group. A majority of the students were Christian (n = 183; 88.0%), received a bursary (n = 183; 88.0%), and had a rural background (n = 155; 74.5%). However, a small percentage of students reported a history of psychiatric and chronic illnesses (n = 26; 12.5%) and previously received professional psychological support (n = 38; 18.3%). In this study, 38% (n = 79) of the participants reported GAD and 67.8% (n = 141) reported symptoms of depression. Significant associations (p <0.05) were observed between variables such as year of study, repeating a module, and history of psychiatric illness with total GAD-7 and PHQ-9 scores. Correlation analysis revealed a moderate positive correlation (rs = 0.400, df = 206, p < 0.001) between total GAD-7 and PHQ-9 scores. Conclusions: This study identified a high level of depression and anxiety among medical students and found a positive correlation between anxiety and depression scores. Addressing these mental health challenges is crucial not only for the well-being of the students but also for the future of healthcare, as the mental health of medical professionals directly impacts patient care.

The factor structure of the Patient Health Questionnaire-9 in stroke: A comparison with a non-stroke population

BACKGROUND

It is unclear if certain post-stroke somatic symptoms load onto items of the Patient Health Questionnaire-9 (PHQ-9), a self-report depression questionnaire. We investigated these concerns in a stroke sample using factor analysis, benchmarked against a non-stroke comparison group.

METHODS

The secondary dataset constituted 787 stroke and 12,016 non-stroke participants. A subsample of 1574 comparison participants was selected via propensity score matching. Dimensionality was assessed by comparing fit statistics of one-factor, two-factor, and bi-factor models. Between-group differences in factor structure were explored using measurement invariance.

RESULTS

A two-factor model, consisting of somatic and cognitive-affective factors, showed better fit than the unidimensional model (CFI = 0.984 versus CFI = 0.974, p < .001), but the high correlation between the factors indicated unidimensionality (r = 0.866). Configural invariance between stroke and non-stroke was supported (CFI = 0.983, RMSEA = 0.080), as were invariant thresholds (p = .092) and loadings (p = .103). Strong invariance was violated (p < .001, ΔCFI = -0.003), stemming from differences in the tiredness and appetite intercepts. These differences resulted in a moderate overestimation of depression in stroke when using a summed score approach, relative to the comparison sample (Cohen's d = 0.434).

CONCLUSIONS

The findings suggest that the PHQ-9 measures a single factor in stroke. Because stroke patients may report higher tiredness on item 4, caution is advisable when classifying patients as depressed if they are near the cut-off and have significant post-stroke fatigue. Caution is also advised when comparing total scores between stroke and other populations.

Comparing the Symptomatology of Post-stroke Depression with Depression in the General Population: A Systematic Review

Previous research into the phenomenological differences of post-stroke depression (PSD) has typically focused on comparisons of symptom profiles between stroke and non-stroke population controls. This systematic review aimed to synthesize these findings with results from other methodological approaches that contribute to an understanding of phenomenological differences. Articles were identified via a systematic search of seven databases and additional manual searching. A narrative synthesis approach was adopted because of the high methodological heterogeneity. Twelve articles comparing the symptomatology of depression between stroke and non-stroke controls were included. Three distinct methodological approaches, relevant to the aim, were identified: comparisons of profiles among groups with similar overall depression severity, comparisons of the strengths of correlations between a symptom and depression, and comparisons of latent symptom severity. The symptomatology of depression was generally similar between the groups, including somatic symptoms, despite the hypothesized interference of comorbid physical stroke effects. Despite high heterogeneity, there was a tentative indication that post-stroke depression manifests with comparatively less severe/prevalent anhedonia. Possible mechanisms for the observed similarities and differences are explored, including suggestions for future research.

Rasch analyses of the Quick Inventory of Depressive Symptomatology Self-Report in neurodegenerative and major depressive disorders

Background

Symptoms of depression are present in neurodegenerative disorders (ND). It is important that depression-related symptoms be adequately screened and monitored in persons living with ND. The Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR) is a widely-used self-report measure to assess and monitor depressive severity across different patient populations. However, the measurement properties of the QIDS-SR have not been assessed in ND.

Aim

To use Rasch Measurement Theory to assess the measurement properties of the Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR) in ND and in comparison to major depressive disorder (MDD).

Methods

De-identified data from the Ontario Neurodegenerative Disease Research Initiative (NCT04104373) and Canadian Biomarker Integration Network in Depression (NCT01655706) were used in the analyses. Five hundred and twenty participants with ND (Alzheimer's disease or mild cognitive impairment, amyotrophic lateral sclerosis, cerebrovascular disease, frontotemporal dementia and Parkinson's disease) and 117 participants with major depressive disorder (MDD) were administered the QIDS-SR. Rasch Measurement Theory was used to assess measurement properties of the QIDS-SR, including unidimensionality and item-level fit, category ordering, item targeting, person separation index and reliability and differential item functioning.

Results

The QIDS-SR fit well to the Rasch model in ND and MDD, including unidimensionality, satisfactory category ordering and goodness-of-fit. Item-person measures (Wright maps) showed gaps in item difficulties, suggesting poor precision for persons falling between those severity levels. Differences between mean person and item measures in the ND cohort logits suggest that QIDS-SR items target more severe depression than experienced by the ND cohort. Some items showed differential item functioning between cohorts.

Conclusion

The present study supports the use of the QIDS-SR in MDD and suggest that the QIDS-SR can be also used to screen for depressive symptoms in persons with ND. However, gaps in item targeting were noted that suggests that the QIDS-SR cannot differentiate participants falling within certain severity levels. Future studies would benefit from examination in a more severely depressed ND cohort, including those with diagnosed clinical depression.

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.