The difference in reduction from baseline between THC and placebo was not significant ( mean difference NPItotal : 3.2 , 95 % confidence interval [ CI ] -3.6 to 10.0 ) , nor were changes in scores for agitation ( Cohen-Mansfield Agitation Inventory 4.6 , 95 % CI -3.0 to 12.2 ) , quality of life ( Quality of Life-Alzheimer 's Disease -0.5 , 95 % CI -2.6 to 1.6 ) , or activities of daily living ( Barthel Index 0.6 , 95 % CI -0.8 to 1.9 ) .