REN and dementia: However, as regards specific antihypertensive treatment, reviews and meta-analyses have shown somewhat different results, with one review stating, that “antihypertensive drugs, particularly calcium channel blockers and renin–angiotensin system blockers, may be beneficial in preventing cognitive decline and dementia”, but also that “randomized controlled trials and meta-analyses have sometimes produced conflicting results, but these are probably due to methodological considerations”, (Rouch et al. 2015).