The stages of change, also known as the Transtheoretical Model (TTM), describe the process people go through to change their behavior. This model, developed by James Prochaska and Carlo DiClemente in the late 1970s, includes the following stages:

1. Precontemplation: In this stage, individuals do not intend to take action in the foreseeable future (usually defined as within the next six months). They may be unaware that their behavior is problematic or may not have the motivation to change.
2. Contemplation: At this stage, individuals recognize that their behavior is problematic and start to consider the pros and cons of their continued actions. They intend to take action within the next six months.
3. Preparation (or Determination): Individuals are ready to take action soon (within the next 30 days). They start to take small steps toward the behavior change and believe that changing their behavior can lead to a healthier life.
4. Action: In this stage, individuals have recently changed their behavior (defined as within the last six months) and intend to keep moving forward with that behavior change. They work on strengthening their commitment to the new behavior.
5. Maintenance: Individuals have sustained their behavior change for more than six months and work to prevent relapse. They are more confident in their ability to continue the new behavior.
6. Termination: This stage is not always included, as not all behaviors reach this stage. In termination, individuals have no desire to return to their unhealthy behaviors and are sure they will not relapse. This stage is often considered the ultimate goal for many behavior changes.
7. Relapse (often included as part of the model, though not a separate stage): Relapse can occur during any stage of the process, and it refers to the individual returning to their old behaviors. When relapse happens, individuals may feel discouraged, but the model emphasizes the importance of learning from the relapse and trying again.

Understanding these stages can help in developing strategies and interventions that are appropriate for the individual’s current stage of change, thereby increasing the likelihood of successful behavior change.