During recent decades there has been growing public and scientific interest into the applications of Buddhist practices and principles for improving psychological wellbeing, and for enhancing psychosocial functioning more generally. Although there is a growing and credible evidence base that supports the utility of Buddhist techniques for treating specific mental health issues, these techniques were originally taught by the Buddha in the context of a spiritual path, and with the complete liberation from suffering as the ultimate goal. Consequently, an increasing number of researchers, scholars, and Buddhist teachers have raised concerns that the manner in which Buddhist meditation techniques are being taught and practised in Western mental health settings bears little or no resemblance to the traditional Buddhist approach. Furthermore, concerns have also been raised over the extent to which the average researcher and teacher of secular Buddhist-derived interventions (BDIs) has an accurate and grounded understanding of the basic principles of Buddhist meditation. The purpose of this doctoral thesis is to make an original contribution to knowledge by: (i) providing robust theoretical foundations to support the effective interpretation, classification, and operationalisation of Buddhist terms, principles, and practices within mental health settings, and (ii) empirically investigating the benefits to mental health of authentic Buddhist practices and principles within currently unexplored population settings. Findings from this thesis demonstrate that BDIs—when correctly taught and administered—may be effective treatments for a range of mental health issues including schizophrenia, pathological gambling, work addiction, and work-related stress. However, perhaps of greater significance, findings demonstrate that if Western research and mental health disciplines truly wish to assimilate and make use of Buddhist practices as part of alleviating human suffering and advancing understanding of the mind, then it is vital that empirical investigations look beyond the superficial attributes of these spiritual practices and seek to identify the cooperating and underlying psycho-spiritual properties that are traditionally assumed to authenticate them.