Bradley Schiller, author of a popular (though not the most popular) introductory economics textbook, says
President Barack Obama has turned fearmongering into an art form. He has repeatedly raised the specter of another Great Depression....Mr. Obama's analogies to the Great Depression are not only historically inaccurate, they're also dangerous. Repeated warnings from the White House about a coming economic apocalypse aren't likely to raise consumer and investor expectations for the future. In fact, they have contributed to the continuing decline in consumer confidence that is restraining a spending pickup.
I am not convinced. In light of the diverse sources of information that the typical person receives, and the natural skepticism about what any politician says, I doubt that any president's rhetoric has a substantial influence on confidence.