"We found that an antidepressant worked as well in severely agitated patients suffering from Alzheimer's disease as an antipsychotic," said Dr. Bruce Pollock, the study’s lead researcher and psychiatrist with Baycrest. "And citalopram had fewer side effects."

Pollock said he and his colleagues were especially surprised by citalopram’s effectiveness in treating psychotic symptoms such as delusion and visual hallucinations.

"But the thing that was the biggest surprise to us was that we didn't hypothesize this," said Pollock. "We thought that citalopram would be better for agitation -- impulsivity and aggression -- which we know SSRIs help with, but the so-called psychotic symptoms were treated as well with the antidepressant as they were with the antipsychotic."

Pollock noted these findings should provide some reassurance for families of Alzheimer’s patients, who wrestle with psychotic symptoms in their loved ones. "The most disturbing part for families and caregivers are the psychotic symptoms, and often these take the form of what we call paranoid delusions or often visual hallucinations, although they could be auditory as well," Pollock told The Canadian Press (CP) news agency.

While noting that more research is necessary, Pollock suggests families of Alzheimer’s patients could ask doctors to try the antidepressant if side-effects from the antipsychotic appear intolerable.

"We tell them (families) it's a question of risk-benefit, but also carefully monitoring the individual person," he told CP. "And that's true with any of these drugs -- not piling on a lot of different ones, really trying to see whether it's making any difference and certainly watching out for side-effects with the antidepressant or the antipsychotic."

"And then," he added, "if things settle down, not keeping the patient on the medication forever."