Social anxiety disorder (SAD) is a common anxiety disorder with a year prevalence rate of 4.8% in the general population. SAD patients show an intense fear of social interactions and social evaluations, which has a negative impact on social functioning, working- and family life and close relationships. As an internalizing disorder, SAD often goes unnoticed as social anxious individuals shy away from social situations or stay in the background. Importantly, however, SAD is a life-long disease with a low likelihood of spontaneous remission. In addition, SAD is argued as a precursor of other (comorbid) anxiety disorders, depression, and substance abuse disorders, stressing the importance for developing preventive intervention strategies for SAD. The main focus of the research program is to gain insight into the risk and protective factors that play a significant role in the development and maintenance of SAD.
In delineating the risk and protective factors amenable to the development and maintenance of SAD, a family-study approach will be employed. It has been shown that both genetic and environmental factors are involved in the development of SAD. For example, twin-studies yielded SAD heritability estimates of 20-50%. To date, however, it remains unclear which genes are specifically involved in (the development of) SAD.
A family-study can reveal important information about the shared (heritable) factors that contribute to the SAD-symptomatology, which relates to behavioral, physiological, and neurological abnormalities. We will investigate whether SAD-symptoms are heritable, and can thus be found in family members of SAD patients. This approach is also referred to as an endophenotype approach, and will facilitate the investigation of gene-environment interactions, a subsequent phase in this research program.
The determination of genetic kinship of the SAD symptomatology is essential for endophenotyping, therefore we will not only examine SAD patients, but also their family members. As the symptomatology of SAD patients is evident on both the behavioral, physiological, and neurological level, we will employ a wide range of methods to fractionate SAD endophenotypes. Psychodiagnostic interviews and various questionnaires will be administered to characterize the clinical-behavioral profile of the participants. In addition, neuroimaging tools (EEG, structural and functional MRI) will be employed to characterize aberrant brain structure and function, which may be closely related to the clinical-behavioral profile. For example, during the neuroimaging test sessions, participants will be lying in a MRI scanner and perform a socially relevant task, while at the same time, their brain activity related to this task will be measured.