This is a reasonable question and difficult to predict. Research shows that the duration of therapy is variable and can be influenced by the specific therapy interventions used, the strength of the relationship with your therapist, as well as factors specific to you. These other factors may include your goals, personal characteristics, the nature, severity, chronicity, and complexity of the problem(s) you are experiencing, external factors such as what else is happening in your life and available social support, the extent to which you actively engage in the treatment, and how comfortable you are with making changes.
Depending on your specific needs and goals, therapy can be short-term, for a specific issue, or longer-term, to deal with recurrent life patterns or your desire for more in-depth personal growth. Some clients experience significant improvement very quickly (4-8 sessions) but generally treatment length ranges from 12-20 sessions for issues such as moderate anxiety or depression. More pervasive or chronic patterns of thinking, feeling, or behaving may require longer term treatment. Therapy is a collaborative process and your progress and goals will be discussed during the course of treatment.