Willie Rennie, the Scottish Liberal Democrat leader, said more than 1,500 young people were having to wait more than a year for mental health support.
And he said the pandemic had also highlighted the need to improve the country's care sector, and the lack of support for schoolchildren who had lost out on education.
He said: "I've seen a window into the next five years in the last few weeks - arguments over the constitution, strategy about independence, arguments between Nicola Sturgeon and Alex Salmond which have been poisonous and unpleasant.
"What we need to do is to put all of that behind us and choose a different future.
"And if we can do that we can tackle mental health, we can tackle education, but we can also make sure our social care workers get the pay they deserve."