Many governments, and private-sector medical companies, limit the number of sessions of psychotherapy that people are entitled to. This is done on financial grounds but there is a lack of research into how many sessions people actually need to get better. A team of researchers, led by Paul Harnett from the University of Queensland, studied this issue by tracking the progress of 125 people as they started psychological treatment. The researchers found that it took 8 sessions for 50% of the clients to show some signs of recovery and 21 sessions for 85% of people to do so. To make a full recovery it took 14 sessions for 50% of the clients to have recovered and 23 sessions for 70% of them to get better. This was much less than the present policies of both the public and private sector in Australia and the researchers recommended a minimum number of 20 sessions for people.
Harnett, Paul, O'Donovan, Analise and Lambert, Michael J. - The dose response relationship in psychotherapy: implications for social policy Clinical Psychologist July 2010, 14(2), 39-44