This is the online supplement to a study to identify therapists' prototypes of four common mental disorders. Although earlier studies concluded that clinicians’ prototypes of patients with mental disorders can influence diagnostic decisions, it remains unclear how presumably more or less prototypical features were identified in these studies in the first place. As research on the content of therapists’ prototypes of mental disorders is very limited, the aim of the current study was to identify therapists’ prototypes of major depression, generalized anxiety disorder, borderline personality disorder, and bipolar disorder. Psychotherapists (N=69) filled out an online survey and answered questions on the most common thoughts, feelings, behaviors, appearance, life circumstances, age, and gender of a person with each disorder. Additionally, they rated the DSM-5 criteria according to how much they think about each criterion when thinking about a typical person with the respective disorder. The most frequently mentioned features of a typical person with each disorder are reported and positive and negative associations between features are visualized by means of network analyses . Besides some exceptions, therapists’ responses were mostly in line with the DSM-5 criteria and with frequencies of symptoms in patients with each disorder. Therapists’ prototypes might be helpful to make diagnostic decisions in typical situations but could lead to incorrectly diagnosing or overlooking a disorder in less typical situations. The results of the current study should be used to increase therapists’ awareness of prototypes and to emphasize the importance of accurate diagnosis, e.g. with structured interviews. Further research should investigate the influence of the prototypical features identified in the current study on therapists’ diagnostic decisions.

Information on Research Data: The file "Kroeber et al 2023 Data.csv" includes the raw data and the file "Kroeber et al 2023 Codebook.csv" includes the corresponding codebook. To evaluate the open questions about thoughts, feelings, behaviors, appearance, and life circumstances of a typical person with BPD, GAD, or MD participants’ responses were categorized into features and interrater reliabilities for the features were calculated. The files "BPD categories 0 1.xlsx", "GAD categories 0 1.xlsx" and "MD categories 0 1.xlsx" include the lists of features coded with 0 = "feature was not mentioned by this participant" or 1 = "feature was mentioned by this participant". These files are used in the submitted R code. The csv-files include the same tables as the excel-files (e.g., "BPD appearance 0 1.csv") as well as the tables with participants' original responses in text form (e.g., "BPD appearance.csv") for long-term archiving. The files "BPD Reliability.zip", "GAD Reliability.zip" and "MD Reliability.zip" include separate excel-files for each feature for calculating interrater reliabilities. These files are used in the submitted R code. Additionally, all tables are included as csv-files for long-term archiving.