Study strengths
depression, anxiety
Our study has several strengths. When collecting the data, questionnaires and measurements were used to cover a wide range of baseline information regarding the clients. With limited missing data (< 3%) and relatively large sample size (Our instruments were standardized and validated with acknowledged cut-offs for the central measures of anxiety (GAD-7) and depression (PHQ-9). The only exception was the OSSS-3 with a Cronbach’s alpha of 0.58. This might imply that the instrument lacked some consistency across questions in this sample, and potentially underestimated the association between social support and dropout. The various instruments used in this study are applied within the PMHC service, which makes it possible to compare results from PMHC within and across countries to other similar services such as IAPT. This contributes to a strengthened external validity and generalizability of our results.When performing the analysis, we included therapists and municipalities as fixed effects. This way, we excluded variations that could be attributed to these factors and thereby reduced the potential for Type I error.