Hell yeah, but it takes training, you are not going to just do it once and be cured, if you've been thinking depressing thoughts, it might take some time to develop a little strength over them.
Mind is like Dirty Water, all the moving thoughts are the dirt particles that stir the water of the mind and make it murky, but when you still the mind, the rest of the dirt drops to the bottom, and the water becomes crystal clear, this is the awareness of mind, with a mind like that you can go further than ever before.
The mind is like a weak muscle in the beginning, it can't lift a lot of weight, but with continued practice, it becomes familiar and easier to do, eventually adding more weight to get stronger at what it is doing. The meditation helps increase the awareness of what you are doing so distraction does not tempt you away.
The Fundamentals of Meditation Practice
http://www.buddhanet.net/pdf_file/chanmed1.pdf
Powers attained thru Concentration
http://www.buddhanet.net/wings_d.htm
