Part II | Vascular risk factors for depression and apathy 89 5 Table 3. Association of vascular factors with amotivation and loss of initiative by multiple linear regression* Amotivation Loss of initiative Vascular risk factors: Beta B (95% C.I.) P-value Beta B (95% C.I.) P-value - Smoking 0.03 0.06 (-0.10-0.22) 0.48 0.08 0.17 (0.00-0.33) 0.04 - Body mass index 0.08 0.02 (0.01-0.03) 0.04 -0.07 -0.01 (-0.03-0.00) 0.08 - Systolic blood pressure 0.01 0.00 (-0.04-0.05) 0.98 -0.07 -0.00 (-0.01-0.00) 0.10 - Diastolic blood pressure 0.02 0.00 (-0.05-0.10) 0.56 -0.06 -0.01 (-0.01-0.00) 0.12 - Ankle brachial Index 0.03 0.19 (-0.34-0.72) 0.49 0.01 0.07 (-0.47-0.62) 0.79 - Diabetes mellitus 0.07 0.34 (-0.01-0.69) 0.06 -0.01 -0.00 (-0.39-0.34) 0.89 Vascular disease: Beta B (95% C.I.) P-value Beta B (95% C.I.) P-value - Cardiac disease 0.01 0.05 (-0.23-0.32) 0.74 0.04 0.13 (-0.15-0.41) 0.38 - Stroke 0.01 0.05 (-0.36-0.45) 0.83 0.02 0.10 (-0.32-0.51) 0.66 * All results have been corrected for age, sex, level of education, mood, physical performance, use of antidepressants, antipsychotics, and benzodiazepines Abbreviations: C.I., Confidence Intervals. Discussion In contrast to our hypothesis, we did not find any association between vascular risk factors or vascular diseases and apathy among people with remitted depression. This finding is in line with a smaller study on apathy in 50 patients who had received electric convulsion therapy (ECT) for severe late-life depression 38. In this study, apathy persisted in 52% of these patients while their depressive disorder had remitted. Nonetheless, the remaining apathy was also not related to MRI-based white matter hyperintensities, vascular disease, diabetes mellitus, or smoking. Collectively, these results imply that remaining apathy in remitted depression is not related to vascular disease and to structural cerebrovascular damage of the fronto-striatal circuitries. How can we explain the lack of any association between vascular risk factors and diseases with remaining apathy after depression? The most likely hypothesis in our opinion stems froma heterogeneous pathophysiology of apathy in combinationwith the specific selection of depressed patients. Just like any other psychiatric disorder, apathy is a behavioral syndrome defined at the phenomenological level. Most studies on the pathophysiology of apathy have been conducted in patients with neurodegenerative disorders, i.e. Alzheimer’s disease or Parkinson’s disease 39 40, or overt cerebrovascular disease like stroke patients 41 42. In these patients, fronto-striatal circuitries are structurally compromised. A recent meta-analysis that pooled data of studies in populations of Alzheimer’s disease patients, stroke patients and healthy elderly persons, found an odds ratio of 1.41 (95% C.I. 1.05-1.89) for apathy in those with a high level of white matter hyperintensities, which is a biomarker for cerebral small vessel disease 43. Based on these findings one might
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