Meditative absorption or concentration can be practiced with or without religious belief, just as yoga may or may not be associated with any religion. Yoga is simply a practice that leads to good health. Likewise, meditation can, by regulating our mentality, bring happiness and cure depression.
The Buddha gave us many methods for cultivating the mind. Whether we believe in the Buddha or not, the mind practices are important to all of us. They can also be practiced by anyone.
~ Depicted from Luminous Wisdom Book Series : The Paper Tiger - The Tibetan Buddhist View on Happiness