My mother has started to fight sleeping. She used to take a nap every day and now fights it and often falls asleep on the couch instead. At night I notice that she gets up and stays up during the night by watching TV or reading. The Dr put her on Risperidone and said it would make her sleepy but it does absolutely nothing.
According to your profile, your mother is 97 and suffers from dementia. My mother is 93 and has HORRIBLE reactions to 95% of ALL medications she's prescribed. She was totally out of control with Cymbalta which works on the serotonin levels in the brain, similar to what Risperidal does. Maybe your mother is simply reacting poorly to this medication, like mine does. That's always my first line of thought whenever she suffers an issue: What new drug is she taking?
Best of luck!