OTTAWA—A review of polling data is giving a new sense of the toll the COVID−19 pandemic is having on the mental health of Canadians, but may also offers clues for how to address it during the holiday season. The review is based on a series of online Leger surveys over the course of the year that were analyzed by the Association for Canadian Studies. Two in three Canadians said in November that they think the current mental health of Canadians is much worse now than it was before the pandemic. More women than men in the surveys thought that was the case. Generally, women report worse mental health than men. About one in five respondents rated their mental health as bad in October, holding steady from the same proportion who said so in March. At the same time, almost half of respondents in an October survey said they were worried …