Alcohol and drug addiction are increasing problems worldwide, for which treatment is considered to be the only solution, if any. However, recent US research has shown that almost half of all persons with a lifetime substance use problem are able to resolve these problems and a large part does so without any professional assistance or self-help support. Although we can learn a lot from such examples of self-change, little is known about ‘natural recovery’. It is commonly assumed that these individuals have less severe problems or receive more social network support, but few studies so far have looked into this phenomenon combining quantitative and qualitative research methods. This study does so, employing Cloud and Granfield’s theory of recovery capital, and looks at natural recovery in comparison with recovery pathways of persons who sought treatment and differences between alcohol, cannabis and other illicit drug users in natural recovery. In addition, we explore the development of natural recovery, based on first-person narratives. This study combines various research methods, starting with a systematic review of the literature on this phenomenon. Based on a large-scale online survey (n>750), recovery experiences will be mapped and compared between persons in ‘natural’ and ‘assisted’ recovery. 60 in-depth interviews with persons in natural recovery will reveal the nature of this phenomenon, individuals’ subjective experiences and its contextual correlates.