Late-life depression is associated with an increased risk for all-cause dementia, vascular dementia and Alzheimer's disease. The present results suggest that it will be valuable to design clinical trials to investigate the effect of late-life depression prevention on risk of dementia, in particular vascular dementia and Alzheimer's disease.

Late-life depression is characterized by slowed information processing, which affects all realms of cognition. This supports the concept that frontostriatal dysfunction plays a key role in LLD. The putative role of some risk factors was validated (eg, advanced age, low education, depression severity), whereas others were not (eg, medical burden, age at onset of first depressive episode). Further studies of neuropsychological functioning in remitted LLD patients are needed to parse episode-related and persistent factors and to relate them to underlying neural dysfunction.

Patients 70 years of age or older with major depression who had a response to initial treatment with paroxetine and psychotherapy were less likely to have recurrent depression if they received two years of maintenance therapy with paroxetine. Monthly maintenance psychotherapy did not prevent recurrent depression. (ClinicalTrials.gov number, NCT00178100.).

Elderly depressed patients with cognitive impairment may experience improvement in specific domains following antidepressant treatment but may not necessarily reach normal levels of performance, particularly in memory and executive functions. This subgroup of late-life depression patients is likely at high risk of developing progressive dementia.

Processing resources are decreased in elderly depressed patients and this decrease in resources appears to mediate impairments in several areas of neuropsychological functioning including episodic memory and visuospatial performance. The resource decrement persists after remission of the depression and thus may be a trait marker of geriatric depression.

One of the most important recommendations to emerge from the meeting discussions is for increased collaboration among clinical and epidemiological investigators whose work focuses in the area of depression with those working primarily in the area of memory disorders. Directions for future research were identified.

Summary Background Treatment-resistant major depressive disorder is common and potentially life-threatening in older persons, in whom little is known about the benefits and risks of augmentation pharmacotherapy. Methods We conducted a multi-site, placebo-controlled, randomized clinical trial to test the efficacy and safety of aripiprazole augmentation for older adults with treatment-resistant depression. We treated 468 participants aged 60 and older with current major depressive episode with venlafaxine extended-release (ER); 96 (20.5%) did not complete this open phase, 191 (40.8%) remitted, and 181 (38.7%) did not remit and were randomized to 12 weeks of double-blind augmentation with aripiprazole or placebo. The computer-generated randomization was done in blocks and stratified by site. The primary endpoint was remission, defined as Montgomery-Asberg Depression Rating Scale scores ≤10 (and at least two points below the score at the start of the randomized phase) at both of the final two consecutive visits. We also assessed resolution of suicidal ideation, and safety and tolerability with cardiometabolic and neurological measures. Analyses were conducted according to the intention-to-treat principle. This trial is registered with ClinicalTrials.gov, number NCT00892047. Findings Older adults on aripiprazole had a higher remission rate than those on placebo (44% versus 29%; odds ratio [OR]=2.0, 95% CI 1.1–3.7, p=0.03; number needed to treat [NNT]=6.6 [95% CI 3.5–81.8]). Overall, remission was stable during 12 additional weeks of continuation treatment. The resolution of suicidal ideation was more marked with aripiprazole than with placebo. Akathisia was the most common adverse effect (27% of participants on aripiprazole). Compared to placebo, aripiprazole was also associated with more Parkinsonism but not with treatment-emergent suicidal ideation, QTc prolongation, or increases in adiposity, glucose, insulin, or lipids. Interpretation In older adults who fail to achieve remission from depression with a first-line antidepressant, the addition of aripiprazole is effective in achieving and sustaining remission. Tolerability concerns include potential for akathisia and Parkinsonism. Funding National Institute of Mental Health, UPMC Endowment in Geriatric Psychiatry, Taylor Family Institute for Innovative Psychiatric Research, National Center for Advancing Translational Sciences, and the Campbell Family Mental Health Research Institute.

These data provide further evidence of structural brain abnormalities in geriatric depression, particularly in patients with a longer course of illness.