Dementia, mood disorders, and aging: Bridging new avenues of care through shared biological pathways.

With advancing age and lifespan throughout the globe in both developed and developing nations, the risk for developing cognitive loss and mood disorders increases significantly to the extent that after reaching the age of 65, this risk almost doubles every 5 years thereafter. As a result, a corresponding rise in non-communicable diseases will impact individuals with dementia and mood disorders involving Alzheimer's disease, multiple sclerosis, depression, and anxiety. On a clinical basis, multiple risk factors and presentations that involve the loss of intellectual capacity with the onset of mental health conditions, mood disorders preceding dementia, sleep fragmentation initiation, perivascular pathway disruptions, and circadian clock dysfunction can occur in both cognitive loss and mood disorders, but a much broader scope of shared underlying cellular pathways form the underpinning for the connection of these disorders that rests upon metabolic disorders, such as diabetes mellitus. Cognitive impairment and mood disorders can precede one another as well as coexist with related co-morbidities that involve metabolic disorders with diabetes mellitus, but present treatment strategies for these disorders are primarily symptomatic in nature and rely upon disease-altering therapies that may slow disease progression but also may be accompanied by disabling complications. Given these challenges, the institution of innovative avenues is critical at this juncture to address the mutual cellular mechanisms for the treatment of disorders involving Alzheimer's disease, multiple sclerosis, depression, and anxiety. The pathways of cell senescence and telomere biology with aging, cellular metabolic dysfunction, apolipoprotein E, oxidative stress, programmed cell death with autophagy, ferroptosis, and pyroptosis, mechanistic target of rapamycin, glucagon-like peptide-1 receptor agonism, mammalian forkhead transcription factors of the "O" class, and mitochondrial dynamics offer a compelling potential to bridge these underlying pathways into unifying strategies for transition into efficacious clinical care for dementia and mood disorders. Tempered with this enthusiasm for these mutual disease mechanisms is the complexity of these pathways that will require meticulous oversight of the interdependence among pathway components and their ultimate biological impact on clinical outcomes.