Grant: Doctoral Award - Frederick Banting and Charles Best Canada Graduate Scholarships

Background: Mood disorder, particularly depression, is a prevalent co-morbidity associated with Alzheimer Disease (60%), Parkinson Disease (50%), and other aging-related conditions such as mild cognitive impairment (15%). For those with dementia, the estimated relative risk of developing depression is 2.01. Numerous reports have documented structural cerebral abnormalities in patients suffering from mood disorder, chiefly atrophy in hippocampus (HC). Similar HC atrophy has been linked to age-related increases in cognitive impairment. The HC is associated with numerous psychological and cognitive functions including memory and attentional control that show clear impairment with increasing age. Despite these associations, an unanswered question concerns whether older adults suffering from depression show increased HC volume atrophy and cognitive impairment. Although evidence clearly shows uniform HC atrophy across the life span in healthy individuals, there is little evidence concerning links between depression, HC atrophy, age, and cognitive impairment. Aim: (1) whether individuals with hippocampal atrophy and mood disorder are at increased risk of developing aging-related cognitive impairment; and (2) whether cognitive impairment in late life varies as a function of mood disorder status (never depressed, previously depressed, currently depressed). Methods: A 2-step approach focused on (A) a meta-analysis (MA), and (B) a unique data collection. (A) MA will systematically examine longitudinal evidence pertaining to abnormal HC volume in middle-aged individuals suffering from mood disorder, and examination of collected data informs on whether older adults (age 65 years and older; N=100) with previously diagnosed mood disorders (potentially linked to HC volumes in step A) also tend to show greater age-related cognitive impairment and whether such impairment is amplified for certain cognitive tasks.