Major depressive disorder subtypes and depression symptoms in multiple sclerosis: What is different compared to the general population?

Assessment of differential item functioning of the PHQ-9, HADS-D and PROMIS-depression scales in persons with and without multiple sclerosis

OBJECTIVE

We tested for the presence of differential item functioning (DIF) in commonly used measures of depressive symptoms, in people with multiple sclerosis (MS) versus people with a psychiatric disorder without MS.

METHODS

Participants included individuals with MS, or with a lifetime history of a depressive or anxiety disorder (Dep/Anx) but no immune-mediated inflammatory disease. Participants completed the Patient Health Questionnaire (PHQ-9), Hospital Anxiety and Depression Scale (HADS), and the Patient Reported Outcome Measurement Information System (PROMIS)-Depression. We assessed unidimensionality of the measures using factor analysis. We evaluated DIF using logistic regression, with and without adjustment for age, gender and body mass index (BMI).

RESULTS

We included 555 participants (MS: 252, Dep/Anx: 303). Factor analysis showed that each depression symptom measure had acceptable evidence of unidimensionality. In unadjusted analyses comparing the MS versus Dep/Anx groups we identified multiple items with evidence of DIF, but few items showed DIF effects that were large enough to be clinically meaningful. We observed non-uniform DIF for one PHQ-9 item, and three HADS-D items. We also observed DIF with respect to gender (one HADS-D item), and BMI (one PHQ-9 item). For the MS versus Dep/Anx groups, we no longer observed DIF post-adjustment for age, gender and BMI. On unadjusted and adjusted analyses, we did not observe DIF for any PROMIS-D item.

CONCLUSION

Our findings suggest that DIF exists for the PHQ-9 and HADS-D with respect to gender and BMI in clinical samples that include people with MS whereas DIF was not observed for the PROMIS-Depression scale.

Depressive symptom trajectories and polygenic risk scores in individuals with an immune-mediated inflammatory disease

OBJECTIVE

To develop group-based trajectories of depressive symptoms in immune-mediated inflammatory disease (IMID) to understand their evolution and identify any associated factors, with the overall goal of identifying those at highest risk of higher depressive symptom burden.

METHOD

922 participants had an IMID or anxiety/depression. The PHQ-9 was administered at four visits, and polygenic risk scores (PRS) for major depressive disorder, depressive symptoms, and body mass index (BMI) were generated. Group-based trajectory modelling of PHQ-9 scores estimated distinct trajectories. Regression tested whether specific factors were associated with the trajectories. Mediation analyses assessed whether IMID mediated the association between BMI PRS and trajectories.

RESULTS

Three trajectories were identified. Regression demonstrated those in Group 3 ('high symptoms') had significantly higher PRS for the three traits, compared to Group 1 ('minimal symptoms') (OR: 1.34-1.66, P < 0.01). Stratified analyses in the IMID subgroup revealed an increased effect for BMI PRS in Group 3 (OR: 2.31, P < 0.001), in contrast, BMI PRS was no longer associated in the non-IMID sample. No significant indirect effect of BMI PRS on depressive symptoms trajectories was identified via IMID.

CONCLUSIONS

A significant association between polygenicity and PHQ-9 trajectories supports a role for genetic inheritance in the variability in depressive symptoms in IMID.

Higher-quality diet and non-consumption of meat are associated with less self-determined disability progression in people with multiple sclerosis: A longitudinal cohort study

Background and purpose

Modifiable lifestyle factors, including diet, may affect clinical outcomes in multiple sclerosis (MS). This study assessed the relationships between diet, and disability, fatigue, and depression risk in people with MS.

Methods

Participants from the Health Outcomes and Lifestyle In a Sample of people with Multiple sclerosis (HOLISM) international cohort were assessed over 2.5 years. Dietary data were obtained using a modified Diet Habits Questionnaire (DHQ), disability using the calculated Patient‐determined MS Severity Score (P‐MSSS), fatigue using the Fatigue Severity Scale, and depression risk using the Patient Health Questionnaire‐2. Participants reported whether they were experiencing symptoms due to a recent relapse. Cross‐sectional and prospective relationships of diet and disease outcomes were explored, adjusted for relevant confounders.

Results

Among 1,346 participants, higher DHQ scores showed significant dose‐dependent associations with lower frequencies of severe disability, fatigue, and depression risk, cross‐sectionally. Prospectively, higher baseline DHQ scores were associated with a lower risk of increasing disability, those above the median having 41% and 36% lower risk of increasing disability, and 0.30 P‐MSSS points less disability progression, but were not associated with fatigue or depression risk. Meat consumption was associated with 0.22 P‐MSSS points higher disability cross‐sectionally, while prospectively, baseline meat consumption was associated with 76% higher risk of increasing disability and 0.18 P‐MSSS points higher disability progression. Dairy consumption showed mixed associations cross‐sectionally and prospectively.

Conclusions

These results show that better quality of diet, as well as not consuming meat, were associated with reduced disability progression in people with MS. Substantiation of these findings in other settings may inform opportunities to manage disability progression in people with MS using dietary modifications.