The Validation of the Young Schema Questionnaire. Focus on early maladaptive schemas and their relationship with eating and substance use disorder symptoms

In 1990, Jeffrey Young developed the concept of early maladaptive schemas (EMS) to account for the dysfunctional beliefs in individuals with chronic characterological problems. He developed the Schema-Focused Cognitive Therapy to treat these conditions (Young, 1990). Schema Therapy, as it is now called, has been increasingly applied in patient samples with several psychiatric disorders, such as mood disorders, eating disorders (ED) and substance use disorders (SUD) as well as in patients with personality disorders (e.g. borderline personality disorder) (e.g., Ball & Young, 2000; Ohanian, 2002). Central in the Schema Theory are the EMS which develop through an interaction of negative childhood experiences and temperament. Within the schema theory, EMS are believed to contribute to the development and maintenance of psychological symptoms. A specific questionnaire, the Young Schema Questionnaire (YSQ) was developed to assess these EMS (1990). Throughout the years, several versions of the YSQ were developed to measure the EMS.

This PhD project focuses on two research lines within the framework of the Schema Theory of Young: (1) the psychometric properties of the YSQ 2nd version – Long Form (YSQL2), and (2) the relationship between EMS and eating and substance use disorder symptoms. The first research line consists of 4 studies. Study 1 investigates the psychometric properties of the YSQL2 in a clinical sample of patients with a SUD or an ED. Study 2 investigates the psychometric properties of a shorter version of the YSQL2 (i.e., the YSQ-SF16) in a Flemish community sample. Study 3 addresses the age neutrality of the YSQL2 in patients with SUD and study 4 investigates the age neutrality of the YSQ-SF16 in a Flemish community sample. The second research line focuses on differences in EMS between different patient groups and consists of two studies. Study 5 compares differences in EMS between patients with ED (Restrictive versus Purging subtype) and the presence/absence of Non-Suicidal Self-Injury. Study 6 compares similarities and differences in EMS between patients with ED (Restrictive versus Purging type) and patients with SUD.

This PhD dissertation is concluded with a summary of the main findings and a discussion of the strengths and limitations of the studies. Finally, recommendations for future research and a discussion of the clinical implications of our findings are formulated.