As our understanding of the neurobiology of Alzheimer Disease deepens, it has become evident that early intervention is critical to achieving successful therapeutic impact. The availability of diagnostic criteria for preclinical Alzheimer Disease adds momentum to research directed at this goal and even to prevention. The landscape of therapeutic research is thus poised to undergo a dramatic shift in the next 5-10 years, with clinical trials involving subjects at risk for Alzheimer Disease who have few or no symptoms. These trials will also likely rely heavily on genetics, biomarkers, and or risk factor stratification to identify individuals at risk for Alzheimer Disease. Here, we propose a conceptual framework to guide this next generation of pharmacological and non-pharmacological clinical pursuit, and discuss some of the foreseeable ethical considerations that may accompany them.

Presented herein is evidence for criterion, content, and convergent/discriminant validity of the NIMH-Provisional Diagnostic Criteria for depression of Alzheimer's Disease (PDC-dAD) that were formulated to address depression in Alzheimer's disease (AD). Using meta-analytic and systematic review methods, we examined criterion validity evidence in epidemiological and clinical studies comparing the PDC-dAD to Diagnostic and Statistical Manual of Mental Disorders fourth edition (DSM-IV), and International Classification of Disease (ICD 9) depression diagnostic criteria. We estimated prevalence of depression by PDC, DSM, and ICD with an omnibus event rate effect-size. We also examined diagnostic agreement between PDC and DSM. To gauge content validity, we reviewed rates of symptom endorsement for each diagnostic approach. Finally, we examined the PDC's relationship with assessment scales (global cognition, neuropsychiatric, and depression definition) for convergent validity evidence. The aggregate evidence supports the validity of the PDC-dAD. Our findings suggest that depression in AD differs from other depressive disorders including Major Depressive Disorder (MDD) in that dAD is more prevalent, with generally a milder presentation and with unique features not captured by the DSM. Although the PDC are the current standard for diagnosis of depression in AD, we identified the need for their further optimization based on predictive validity evidence.

Background Survival estimates are integral to care for patients diagnosed with dementia. Few Canadian studies have carried out long-term follow-up of well-described cohorts, analyzing survival related to multiple risk factors. Methods Survival analysis of an inception cohort enrolled at a British Columbia (BC) tertiary dementia referral clinic between 1997 and 1999 was undertaken. Vital status was completed for 168 patients diagnosed with dementia. An evaluation of the effects of demographics, vascular risk factors, cognitive and functional ratings, apolipoprotein 4-status, and cholinesterase use on survival was performed using a log-rank test and time-dependent Cox regression. Survival of this dementia cohort was compared with the age-matched life expectancy of persons in BC. Results In all, 158/168 (94.0%) subjects died over 16.6 years, with a median survival of 7.08 years. Risk factors associated with shorter survival in dementia groups included age of onset ≥80 (hazard ratio [HR] 1.56, 95% confidence interval [CI] 1.05-2.32); greater functional disability (Disability Assessment for Dementia<55% [HR 1.47, 95% CI 1.04-2.08]); and cumulative medical illness severity (Cumulative Illness Rating Scale≥7 [HR 1.51, 95% CI 1.08-2.12)]. Compared with the BC population, years of potential life lost for dementia subjects aged <65 was 15.36 years, and for dementia subjects aged ≥80 it was 1.82 years. Conclusions Survival in dementia subjects is shorter than population life expectancies for each age strata, with greatest impact on younger patients. For people diagnosed with dementia, age ≥80 years, cumulative medical illness severity, and functional disabilities are the most significant survival predictors and can be used to guide prognosis.