The developmental trajectory of bipolar disorder: Is ADHD a risk syndrome?

There is increasing recognition that major psychiatric disorders, including bipolar disorder, evolve from non-specific early antecedents or risk syndromes. Given the substantial heritability of these disorders, longitudinal studies of offspring of affected parents over the risk period can map the natural history, identifying predictive risk syndromes and separate these from burden of illness effects. Longitudinal high-risk research can also identify overlapping and differentiating aspects of different illness trajectories. This information is critical to refining the phenotype, identifying genetically sensitive causal pathways and biomarkers and identifying early intervention targets. Ultimately, in psychiatry we need to go beyond cross-sectional symptom based diagnoses and understand the early stages of different disease processes, and refine our diagnoses by associated clinicopathological staging systems. This paper summarizes key findings with regard to the early clinical stages of bipolar disorder based on longitudinal high-risk research and addresses specifically the relationship with attention deficit disorder with hyperactivity (ADHD), often postulated as a putative risk syndrome.