“…Two studies (6.67%; Heinonen, Knekt, Jääskeläinen, & Lindfors, ; Heinonen, Lindfors, Laaksonen, & Knekt, ) used a quasi‐experimental design with a 3‐ and 5‐year follow‐up from the start of treatment, respectively. In these studies, the average treatment duration ranged from 20 sessions to 3 years (Heinonen et al, ) and from 31.3 to 56.3 months (Heinonen et al, ). In one study (3.33%; Black, Hardy, Turpin, & Parry, ), therapists were surveyed through a postal questionnaire and treatment duration was not reported.…”