The article describes part of an on-going research on the processes of mental liberation and growth. The original research material is based on qualitative research methods and ethnographic in-depth interviews with drug-addicted persons undergoing treatment. The material is further analysed within a framework presented in Kazimierz Dabrowski's theory: mental growth through positive disintegration. This framework was found to be useful in the analysis of the participants’ mental growth processes particularly due to the integration of human's transcending ability. Participants contribute in (...) describing how transformative existential experiences may promote the process of mental growth. Importance of activating the mental transcending ability is shown to be central in the recovery process. One profound transformative existential experience is described as the possibility to be who you are, an identity experience which elicited the genuine self. The study sheds light on human mental development when the therapy included activation of the spiritual/religious dimension. (shrink)