A report from the Montreal Geriatric University Institute in November of 2012 reviewed 68 trials on benzodiazepines, 12 on antihistamines, and 15 on tricyclic antidepressants and concluded that these families of drugs have a significant negative impact on memory and concentration in the elderly. The American Geriatrics Society proclaimed that these drugs should not be used in the elderly.
These drugs bind to cholinergic, histamine, GABAergic, and opoiod receptors in the brain and cause problems in cognitive function and in memory.