"Mindfulness meditation programs improved multiple dimensions of negative affect, including anxiety, depression, and perceived stress/general distress ... the effects were significant for anxiety and marginally significant for depression at the end of treatment, and these effects continued to be significant at 3-6 months for both anxiety and depression"
http://en.wikipedia.org/wiki/Mindfulness_(psychology)#Overal...
"[Loving-kindness] meditation practice produced increases over time in daily experiences of positive emotions, which, in turn, produced increases in a wide range of personal resources (e.g., increased mindfulness, purpose in life, social support, decreased illness symptoms)."
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3156028/
A recent meta-analysis:
http://archinte.jamanetwork.com/article.aspx?articleid=18097...
Meditation is pretty easy, and definitely cheap- definitely worth trying yourself :)