Alzheimers is thought to be caused in part by the buildup of amyloid plaques. That is, misfolded proteins (prions) and other bio gunk that clogs up synapses. Now with evidence showing microplastics are crossing the blood brain barrier, we can expect an exacerbation of alzheimers and it's symptoms. More and more people will be wracked with dementia at increasingly earlier stages of life.
we're destroying ourselves and our environment at roughly the same rate, and if you've paid any attention to how the environment is doing, you'll know that that rate is terrifying, and rising unabated.