Network structure of time-varying depressive symptoms through dynamic time warp analysis in late-life depression.

OBJECTIVES: Late-life major depressive disorder (MDD) can be conceptualized as a complex dynamic system. However, it is not straightforward how to analyze the covarying depressive symptoms over time in case of sparse panel data. Dynamic time warping (DTW) analysis may yield symptom networks and dimensions both at the patient and group level. METHODS: In the Netherlands Study of Depression in Older People (NESDO) depressive symptoms were assessed every 6 months using the 30-item Inventory of Depressive Symptomatology (IDS) with up to 13 assessments per participant. Our sample consisted of 182 persons, aged ≥ 60 years, with an IDS total score of 26 or higher at baseline. Symptom networks dimensions, and centrality metrics were analyzed using DTW and Distatis analyses. RESULTS: The mean age was 69.8 years (SD 7.1), with 69.0% females, and a mean IDS score of 38.0 (SD = 8.7). DTW enabled visualization of an idiographic symptom network in a single NESDO participant. In the group-level nomothetic approach, four depressive symptom dimensions were identified: "core symptoms", "lethargy/somatic", "sleep", and "appetite/atypical". Items of the "internalizing symptoms" dimension had the highest centrality, whose symptom changes over time were most similar to those changes of other symptoms. CONCLUSIONS: DTW revealed symptom networks and dimensions based on the within-person symptom changes in older MDD patients. Its centrality metrics signal the most influential symptoms, which may aid personalized care.

Dynamic time warp analysis of individual symptom trajectories in depressed patients treated with electroconvulsive therapy.

BACKGROUND: Although electroconvulsive therapy (ECT) effectively improves severity scores of depression, its effects on its individual symptoms has scarcely been studied. We aimed to study which depressive symptom trajectories dynamically cluster together in individuals as well as groups of patients during ECT using Dynamic Time Warp (DTW) analysis. METHODS: We analysed the standardized weekly scores on the 25-item abbreviated version of the Comprehensive Psychopathological Rating Scale (CPRS) in depressed patients before and during their first six weeks of ECT treatment. DTW analysis was used to analyse the (dis)similarity of time series of items scores at the patient level (300 'DTW distances' per patient) as well as on the group level. Hierarchical cluster, network, and Distatis analyses yielded symptom dimensions. RESULTS: We included 133 patients, 64.7% female, with an average age of 60.4 years (SD 15.1). Individual DTW distance matrices and networks revealed marked differences in hierarchical and network clusters among patients. Based on cluster analyses of the aggregated matrices, four symptom clusters emerged. In patients who reached remission, the average DTW distance between their symptoms was significantly smaller than non-remitters, reflecting denser symptom networks in remitters than non-remitters (p=0.04). LIMITATIONS: The assessments were done only weekly during the first six weeks of ECT treatment. The use of individual items of the abbreviated CPRS may have led to measurement error as well as floor and ceiling effects. CONCLUSION: DTW offers an efficient new approach to analyse symptom trajectories within individuals as well as groups of patients, aiding personalized medicine of psychopathology.

Telomere length, oxidative stress, and antioxidant status in elderly men in Zutphen and Crete.

The incidence of chronic diseases such as cardiovascular diseases is lower in Mediterranean Southern Europe than Northern Europe. This may be due to a lower level of oxidative stress and a higher antioxidant status in people living around the Mediterranean Sea. Oxidative stress may influence the rate of shortening of telomeres, the nucleoprotein structures at the ends of chromosomes. We compared leukocyte telomere length (LTL) in elderly men from Northern and Southern Europe and investigated the possible relationship between LTL and indicators of oxidative stress and antioxidant status. We examined 143 elderly Dutch men (mean age 83.9 years) and 109 Greek elderly men (mean age 84.6 years) and found that the Greek men had significantly longer telomeres (geometric mean 4.95 kbp, 95% confidence interval (CI): 4.71-5.23 kbp) compared to the men from the Netherlands (4.76 kbp, 95% CI: 4.55-4.98 kbp; P=0.001). Age was inversely associated with LTL (ß=-0.10, P=0.31 in Cretan men and ß=-0.19, P=0.02 in Dutch men). In all men LTL was not related to indicators of oxidative stress and plasma antioxidants. However, the endogenous antioxidants serum albumin (ß=0.18, P=0.007) and uric acid (ß=0.13, P=0.045) were positively associated with LTL. The age-adjusted difference between Crete and Zutphen was reduced by 25% after adjustment for serum albumin and uric acid. We conclude that Greek elderly men have significantly longer LTL compared to Dutch counterparts. The endogenous antioxidants albumin and uric acid were positively associated with longer telomeres.

Risk of depressive symptoms in the oldest old subjects with chronic obstructive pulmonary disease: the Leiden 85-plus study.

OBJECTIVES: Chronic obstructive pulmonary disease (COPD) has been associated with depression in middle-aged and younger old adults. However, it remains unknown whether COPD contributes to the occurrence of depressive symptoms in the oldest old subjects. The authors aimed to determine whether oldest old persons with COPD are at increased risk of developing depressive symptoms. DESIGN, SETTING, PARTICIPANTS: The authors prospectively followed up 333 subjects from age 85 years onward within the population-based Leiden 85-plus Study. COPD, along with other chronic diseases, was assessed using structured questionnaires and confirmed with the diagnosis of the treating physician. Depressive symptoms were assessed annually using the 15-item version of the Geriatric Depression Scale (GDS-15). Nondepressed subjects with and without COPD at baseline were compared for the occurrence of depressive symptoms during 5 years of follow-up using multilevel analysis. RESULTS: At baseline, COPD was present in 40 subjects (12%) and associated with male gender, lower education, and smoking. During 5 years of follow-up, an additional annual increase of 0.29 points (standard error [SE] = 0.14) in the GDS-score was observed in subjects with COPD, when compared with those without COPD (F[1, 212] = 4.1, p = 0.04). This difference persisted after adjustment for demographics, baseline GDS score, functional limitations, and presence of chronic diseases (F[1, 451] = 4.6, p = 0.03). CONCLUSION: In the oldest old subjects, COPD independently contributes to an increased risk of developing depressive symptoms. Clinicians should be aware of the association of COPD with depressive symptoms in the oldest old to offer them optimal treatment in an early stage.