The St. Göran project - a multi-pronged strategy for longitudinal studies for bipolar disorders.

Introduction: The St. Göran Bipolar Project (SBP) is a longitudinal outpatient study investigation aimed at identifying predictive factors associated with long-term outcomes in individuals with bipolar disorder. These outcomes include cognitive function, relapse rate, treatment responses, and functional outcomes. The study employs a multifaceted approach, integrating brain imaging, biochemical analyses of cerebrospinal fluid and blood, and genetics. This paper aims to provide an overview of the research methods used in the SBP, along with a summary of the main findings to date.

Methods: SBP is a collaborative effort between academia and healthcare, enrolling study participants from bipolar outpatient clinics in Stockholm (SBP-S) and Gothenburg (SBP-G), Sweden. Healthy controls were recruited through Statistics Sweden. Data and samples were collected using structured interviews, self-rated questionnaires, blood and cerebrospinal fluid samples, magnetic resonance imaging, and neuropsychological tests. Follow-up visits are conducted 7 and 14 years after baseline.

Conclusion: The SBP has generated numerous original findings and has contributed to advancing knowledge on cognitive function, personality, cerebrospinal and blood biomarkers, neuroimaging, and genetics. Further, as data collection nears completion, new research questions can be addressed. The study's strengths include detailed, multimodal information from each study visit and a long follow-up period. The naturalistic setting ensures that findings are relevant to real-world scenarios. However, variability in data completeness can introduce selection bias. Additionally, the control population, while randomly selected, may not be fully representative due to the voluntary nature of participation. Future projects will focus on longitudinal analyses and novel methods to exploit the study's multifaceted approach.