TY - JOUR
T1 - Revealing Causal Heterogeneity Using Time Series Analysis of Ambulatory Assessments
T2 - Application to the Association Between Depression and Physical Activity After Myocardial Infarction
AU - Rosmalen, J.G.M.
AU - Wenting, A.M.G.
AU - Roest, A.M.
AU - de Jonge, P.
AU - Bos, Elisabeth
PY - 2012/5
Y1 - 2012/5
N2 - Objective: Studies in psychosomatic medicine are characterized by analyses that typically compare groups. This nomothetic approach leads to conclusions that apply to the average group member but not necessarily to individual patients. Idiographic studies start at the individual patient and are suitable to study associations that differ between time points or between individuals. We illustrate the advantages of the idiographic approach in analyzing ambulatory assessments, taking the association between depression and physical activity after myocardial infarction as an example. Methods: Five middle-aged men who had myocardial infarction with mild to moderate symptoms of depression were included in this study. Four of these. participants monitored their physical activity and depressive symptoms during a period of 2 to 3 months using a daily self-registration form. The time series of each individual participant were investigated using vector autoregressive modeling, which enables the analysis of temporal dynamics between physical activity and depression. Results: We found causal heterogeneity in the association between depression and physical activity. Participants differed in the predominant direction of effect, which was either from physical activity to depression (n = 1,85 observations, unstandardized effect size = -0.183, p=.03) or from depression to physical activity (n = 2, 65 and 59 observations, unstandardized effect sizes = -0.038 and -0.381, p
AB - Objective: Studies in psychosomatic medicine are characterized by analyses that typically compare groups. This nomothetic approach leads to conclusions that apply to the average group member but not necessarily to individual patients. Idiographic studies start at the individual patient and are suitable to study associations that differ between time points or between individuals. We illustrate the advantages of the idiographic approach in analyzing ambulatory assessments, taking the association between depression and physical activity after myocardial infarction as an example. Methods: Five middle-aged men who had myocardial infarction with mild to moderate symptoms of depression were included in this study. Four of these. participants monitored their physical activity and depressive symptoms during a period of 2 to 3 months using a daily self-registration form. The time series of each individual participant were investigated using vector autoregressive modeling, which enables the analysis of temporal dynamics between physical activity and depression. Results: We found causal heterogeneity in the association between depression and physical activity. Participants differed in the predominant direction of effect, which was either from physical activity to depression (n = 1,85 observations, unstandardized effect size = -0.183, p=.03) or from depression to physical activity (n = 2, 65 and 59 observations, unstandardized effect sizes = -0.038 and -0.381, p
KW - time series analysis
KW - ambulatory assessment
KW - depression
KW - physical activity
KW - vector autoregressive models
KW - RISK
U2 - 10.1097/PSY.0b013e3182545d47
DO - 10.1097/PSY.0b013e3182545d47
M3 - Article
VL - 74
SP - 377
EP - 386
JO - Psychosomatic Medicine
JF - Psychosomatic Medicine
SN - 0033-3174
IS - 4
ER -