There is a convergence of finding of the occurrence of cognitive dysfunction in diabetes, obesity, and bipolar and unipolar mood disorders. This is based on new evidence of insulin resistance in the CNS found in examination of exosomes. Insulin is neuroprotective and neurotrophic much like lithium. People on lithium do not have evidence of loss of grey and white matter that others with bipolar disorder who are not on lithium have. Intra-nasal insulin can improve cognition. The widely used insulin sensitizers GLP-1s for diabetes and weight loss appear to also decrease cognitive decline. The GLP-1 liraglutide improves cognition in mood disordered patients, and increases brain NAA in obesity. The GLP-1 semaglutide appears to increase motivation, cognition and overcome reward deficits. These agents could have anti-depressant and depression preventing properties which remain to be further confirmed in ongoing clinical trials.

McIntyre finds that 80% of Alzheimer’s patients are insulin resistant and the GLP-1s are being studied for this illness as well. There is also a convergence of deficits in cognition, motivation, and normal mood in Alzheimer’s patients.

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