Piazza and Deroche-Gamonet have significantly contributed to the field of addiction and published several pioneering articles that have had a major influence on the field. The latest article by Piazza and Deroche-Gamonet is a position paper, in which they argue that they provide a foundation for the first general theory of the transition to addiction. Their theory is composed of the following three principles:(1) The transition to addiction depends on an interaction between individual vulnerability and drug exposure.(2) The transition to addiction involves at least three steps (ie, recreational/sporadic drug use, intensified/sustained/escalated drug use, and loss of control/full addiction).(3) Addiction is a true psychiatric disease. Piazza and Deroche-Gamonet propose to test their “first” general theory of addiction by providing three predictions that can be used to validate or invalidate their theory. The review by Piazza and Deroche-Gamonet represents an excellent opportunity to discuss critical aspects of the transition to addiction. In this article, we attempt to test point by point the validity of their statements based on the current state of the field, with the hope that a better understanding of the addiction process will lead to better treatments for drug addiction. To test the validity of their claims, as suggested by Piazza and Deroche-Gamonet, it is important to define the criteria that need to be fulfilled for a novel theory to be valid. A scientific theory is a well-substantiated explanation of a phenomenon based on knowledge that has been repeatedly confirmed through observation and experimentation. Its strength is related to the diversity of phenomena it can explain and the accuracy in predicting outcomes. A scientific theory should allow for falsifiable predictions. Finally, a new theory should better explain experimental observations than previous theories and result in further testable predictions that can be confirmed. We will review each principle proposed by Piazza and Deroche-Gamonet based on each of these criteria.