These study results were quite interesting:

Research on mice has shown that low doses of THC, the "high" inducing chemical in cannabis, can put the brakes on mental decline.

But the benefits were only seen in older mice, said the researchers.

When young animals were exposed to THC, their memory and learning performance got worse.

THC activates a g protein-coupled receptor and overactivation of these receptors is one of the factors that leads to memory loss (various environmental toxins and pyschological stress also over-activate g protein-coupled receptors).  But g protein-coupled receptor activity declines as Alzheimer's disease progresses, so the negative effects of THC also decline. Then the beneficial effects of THC on memory come to the fore.  Specifically THC is a peroxynitrite scavenger.  Peroxynitrite limits the formation of acetylcholine through oxidation and nitration; the decline in acetycholine levels impedes the retrieval of short-term memory.  THC partially reverses this oxidation and nitration.  It may also help behavior in Alzheimer's disease by reducing levels of norepinephrine.   The conclusion of the authors in the above article make sense:

Cannabis could slow down - or even reverse - memory loss and other brain ageing effects in older people according to scientists.

http://www.birminghammail.co.uk/news/health/cannabis-could-help-reverse-memory-13005800

In addition, cannabidiol and various terpenes in CBD oil are also peroxynitrite scavengers.  So a CBD oil low in THC and high in terpenes may very well lead to improvements in cognition in someone with Alzheimer's disease.

Hi Lane, 

I've been reading about THC and CBD and gotten my mother's geriatric doctor to okay the use of medical marijuana.  I've seen a couple different studies - the Israeli study that had 11 people try 2.5 mg of THC 2x a day, and that it helped with anxiety, aggression, delusions, apathy, irritability.  And then another study that studied combining CBD and THC for even more benefit.

My mother will accept pills, more easily than drops or treats.  I found some by a company called Procana that are 2:1 CBD:THC, with 5 mg CBD and 3 mg THC.   Is that a decent starting point?   I live in a legal medical marijuana state, so there are lots of local dispensaries.

Unfortunately,  I don't have any experience using CBD oil for the treatment of Alzheimer's disease.  I only really found out about it as a treatment after my mother had died.  I have read quite a few different recommendations on Alzconnected and other websites.  I think that the ratio may vary from person to person.  It seems like a 5:1 ratio (cannabidiol to THC) (possibly 10mg to 2mg) might be a place to start and then go up or down from that depending upon your mother's response.  I think the terpenes in marijuana may also be helpful, so looking for CBD oil relatively high in terpenes might also be good. 

You might post on the caregiver forum and the younger onset Alzheimer's disease forum to get a more varied and hopefully more accurate response. 

Best wishes to you and to your mother.