Amyloid imaging with [(18)F]florbetapir in geriatric depression: early-onset versus late-onset

We examined patients with mild cognitive impairment (MCI) with a history of geriatric depression (GD) and healthy controls (HC) to evaluate the effect of beta-amyloid (Aβ) pathology on the pathology of GD by using [(18)F]florbetapir PET.

Thirty-three elderly patients (76.7 ± 4.2 years) and 22 healthy controls (HC; 72.0 ± 4.5 years, average ± SD) were examined by [(18)F]florbetapir positron emission tomography (PET) to quantify the standard uptake value ratio (SUVR) as the degree of amyloid accumulation, by MRI to determine the degree of atrophy, by Mini-Mental State Examination for cognitive functions, and by Geriatric Depression Scale for the severity of depression, and by Clinical Dementia Rating for activity of daily living (ADL). The cut-off value of 1.08 for SUVR was defined as Aβ-positive.

Of the patients and HC, 39.4% and 27.3%, respectively, were beta-amyloid-positive. The onset age of GD was significantly correlated with SUVR (r = 0.44, p < 0.01). Compared to patients without Aβ (GD-Aβ), patients with Aβ (GD + Aβ) did not differ in terms of age, cognitive function, severity of depression and ADL, and brain atrophy. GD + Aβ had significantly older average ± SD age at onset of GD (73.6 ± 7.1 versus 58.7 ± 17.8, p < 0.01) and significantly shorter average ± SD time between onset of GD and PET scan day (3.1 ± 5.2 years versus 18.1 ± 18.6 years, p < 0.001) than GD-Aβ.

Our results showed that the rate of Aβ positivity was higher in late-onset GD and that onset-age was associated with SUVR, suggesting that the later the onset of GD, the more Aβ pathology affected its onset.