Which principle relates to the concept of responsivity in drug abuse treatment?

The principle that states "No single treatment is appropriate for everyone" underscores the importance of responsivity in drug abuse treatment. This concept emphasizes that individuals have unique backgrounds, circumstances, and needs that influence how they respond to different treatment approaches. A treatment plan that works for one person may not be effective for another, highlighting the necessity of tailoring interventions to fit the specific characteristics and preferences of each individual.

By acknowledging that a variety of treatment modalities must be used to accommodate differing client needs, practitioners can enhance the effectiveness of drug abuse treatment. This aligns with the responsivity principle, which promotes personalized care to improve outcomes for those in recovery.

The other choices do not capture the essence of responsivity in the same way. For instance, while voluntary participation and treatment settings can be important, they do not directly address the need for individualized treatment approaches, which is at the core of responsivity.