Ten take home lessons from the first 10 years of the CTN and 10 recommendations for the future.

Background: The first 10 years of the National Institute on Drug Abuse's Clinical Trials Network (CTN) yielded a wealth of data on the effectiveness of a number of behavioral, pharmacological, and combined approaches in community-based settings.

Methods: We summarize some of the methodological contributions and lessons learned from the behavioral trials conducted during its first ten years, including the capacity and enormous potential of this national research infrastructure.

Results: The CTN made contributions to the methodology of effectiveness research; new insights from secondary analyses; the extent to which approaches with strong evidence bases, such as contingency management, extend their effectiveness to real world clinical settings; new data on 'standard treatment' as actually practiced in community programs, the extent to which retention remains a major issue in the field; important data on the safety of specific behavioral therapies for addiction; and heightened the importance of continued sustained attention to bridging the gap between treatment and research.

Conclusions: Areas of focus for the CTN's future include defining common outcome measures to be used in treatment outcome studies for illicit drugs; incorporating performance indicators and measures of clinical significance; conducting comparative outcome studies; contributing to the understanding of effective treatments of comorbidity; reaching underserved populations; building implementation science; understanding long-term outcomes of current treatments and sustaining treatment effects; and conducting future trials more efficiently.