Cohort Profile: The St. Göran Bipolar Project

Background The St. Göran Bipolar Project (SBP) was launched as a longitudinal outpatient study investigation. The overarching objective was to identify predictive factors associated with long-term outcomes of individuals with bipolar disorder, encompassing cognitive function, relapse rate, treatment responses, and functional outcome. Furthermore, the aim was to incorporate brain imaging, biochemical analyses of cerebrospinal fluid and blood, and genetics in a multifaceted approach that target several levels of observation. Methods The SBP is a collaboration between academia and healthcare, enrolling individuals treated at the respective bipolar outpatient clinics in Stockholm (SBP-S) and Gothenburg (SBP-G), Sweden. Healthy controls were identified through Statistics Sweden and enrolled at both sites. Data and sample collection included structured interview instruments, self-rated questionnaires, blood and cerebrospinal fluid samples, magnetic resonance imaging, and neuropsychological tests. A subset of study participants has completed 7- and 14-year follow-up visits. Discussion The SBP has generated many original findings and recent studies have used the advantages of longitudinal follow-ups and the presence of a replication cohort. While data collection is approaching completion, collected data continue to be used to address new research questions. The two key strengths of the St. Göran study are the detailed and multimodal information collected at each study visit and the extended follow-up period. The naturalistic setting of the study means findings are often applicable to individuals with bipolar disorder in real-world scenarios. However, the variability in completeness of collected information is substantial for some modalities and drop-out rates between baseline and follow-up study visits can introduce selection bias. Further, though the control population in the study was randomly selected from the general population, it may not be fully representative as recruitment was limited to individuals who actively responded to contact. Trial registration SBP is an observational clinical study, and it was registered on Researchweb (https://www.researchweb.org/is/vgr/project/39411) January 1st 2009 (project ID: 39411).