Does wellbutrin (bupropion) cause less anxiety than ritalin?

Depends: Different people react differently.

Usually: Although both are stimulants, wellbutrin (bupropion) is a weaker stimulant than Ritalin and has a smoother course of action, so it is less apt to cause anxiety; but, it still can happen, especially at high doses. Often, people with adhd who need stimulants but get anxious on them take a second medication to help reduce the anxiety; alternatively, several nonstimulants for adhd don't cause anxiety.