Sadia,

The investigation of spiritual factors in health is clearly warranted and clinically relevant. Spirituality has been found to comprise a unique factor to explain human behavior above and beyond the heritable features that comprise personality. RALPH L. PIEDMONT conduct a research on the Spiritual Transcendence Scale (STS) along with additional attitude and personality measures were administered in an Indian sample of Hindus, Christians, and Muslims. Their results showed structural validity of the STS and predictive validity independent of personality factors, consistent with U.S. samples. Gender differences between the three religions indicated that religiousness and spirituality are not isomorphic constructs. 

You can have a look at:

Cross-Cultural Generalizability of the Spiritual Transcendence Scale in India

Spirituality as a Universal Aspect of Human Experience

RALPH L. PIEDMONT, MARK M. LEACH

doi: 10.1177/0002764202045012011

Spirituality, religion, and health: An emerging research field.

Miller, William R.; Thoresen, Carl E.

American Psychologist, Vol 58(1), Jan 2003, 24-35. doi: 10.1037/0003-066X.58.1.24

Man are born equal but under different environment ,reflecting the behavior depending on his environment .For human being where he touches the spirituality ,he has with him a definite vision under the moral code with an Honest integrity approach for his life-line .

Spirituality depends a faith ,devotion ,something unknown -higher way of life so -to -say ''GOD'' .

In present environment ,whatever the practice one man follow,a person with a good human behavior in any part of the world is bound to be a blessing for the society .

Spirituality is an idea. Ideas tend to motivate action in real time when ideas become belief.

I do believe that individual spirituality can be viewed from two angles. On the one hand that which relate to religiosity founded in the belief systems of the community and/or society that the individual grew up in or are part of. On the other hand spirituality can also be regarded in the light of so-called inner being, that is the individual's quest to become 'self-actualized' by finding a sense of meaning and purpose as well as a sense of community and transcendence. This quest moves beyond individualistic dogma and defines action and behaviour of the individual in the workplace and any other relevant environment he/she deems important.

Since your primary interest is in theory, I would point you to some classical ones. Fowler's Stages of faith discusses different capabilities of the individual at different life stages and Tornstam's Theory of Gerotranscendence is perhaps more applicable in aging, but with some relevancy for any age. His theory was discussed by Joan Erikson in Erik and Joan's later version of The Lifecycle Completed (1997).  Further, Maslow has some undersung work that considers spiritual capabilities of people--he particularly identifies what he terms Being values (spiritual values) and Deficiency values (ones that are less enlightened).

Spirituality, especially spirituality at work or workplace spirituality has been found to have positive impact on employee attitudes and behaviors. However, it is not quite clear whether the effect is direct or there are other mechanisms (mediators) through which spirituality affects behavior. Petchswanga and Duchon's (2012) study found meditation to have partial mediation effect on the relationship between workplace spirituality and work performance.

Sadia,

The investigation of spiritual factors in health is clearly warranted and clinically relevant. Spirituality has been found to comprise a unique factor to explain human behavior above and beyond the heritable features that comprise personality. RALPH L. PIEDMONT conduct a research on the Spiritual Transcendence Scale (STS) along with additional attitude and personality measures were administered in an Indian sample of Hindus, Christians, and Muslims. Their results showed structural validity of the STS and predictive validity independent of personality factors, consistent with U.S. samples. Gender differences between the three religions indicated that religiousness and spirituality are not isomorphic constructs. 

You can have a look at:

Cross-Cultural Generalizability of the Spiritual Transcendence Scale in India

Spirituality as a Universal Aspect of Human Experience

RALPH L. PIEDMONT, MARK M. LEACH

doi: 10.1177/0002764202045012011

Spirituality, religion, and health: An emerging research field.

Miller, William R.; Thoresen, Carl E.

American Psychologist, Vol 58(1), Jan 2003, 24-35. doi: 10.1037/0003-066X.58.1.24

Imho, Spirituality, if I take the definition as "the experience of the individual, with the trancendent being(s), enlightenment with "cosmopsychologically relevant self-knowledge", can have many influences in the human behavior. Spiritually oriented cognitions, usually enhance self-acceptance, self-compassion, constitutes life goals and thus end in meaningful behaviors. Although many spirituality paths encourage followers to higher levels of human functioning, in rare cases, ill-guided spirituality may end in maladaptive behaviors also.

Here is a review of some costs and benefits to religious/spiritual belief by Ken Pargament: http://www.tandfonline.com/doi/abs/10.1207/S15327965PLI1303_02

Here is a social-functionalist account of religion/spirituality by Jonathan Haidt:

http://psr.sagepub.com/content/14/1/140.short

Spirituality essentially creates a state of mind which is not only logical but justifiable too. Philanthropy, for example, maybe an outcome of an intention to serve the humanity again somewhere influenced by spiritual thoughts. On the other side its wrong interpretation might lead to an unaccepted behavior. Since mind governs our philosophies that ultimately results into a desirable behavior. This behavior unlike our normal behavior encompasses a more helpful orientation, lesser greed, no competition but an attempt to help its customers or society in general with non-selfish motive.     

Absolutely! Spirituality forms the major aspect of our SELF beliefs, desires and intentions.