¿Quiénes presentan un trastorno bipolar? Una comparación entre el trastorno depresivo mayor, la ansiedad y el TDAH (Inglés)

Bipolar Disorder (BD) is a common, lifelong mood disorder that affects 2–3 % of the world’s population (Merikangas et al., 2011). Available treatments can be highly effective for some, but not all individuals with BD, many of whom struggle with breakthrough or residual symptoms despite receiving evidence-based therapies (Mignogna and Goes, 2024). While novel treatments targeted to disease related pathophysiology are needed, better and earlier use of currently available therapies may also lead to improved overall outcomes. However, early manifestations of BD rarely include the (hypo)manic symptoms characteristic of the full diagnosis. As a result, it may take an average of 7 years to receive a BD diagnosis (Scott et al., 2022). Such initial misdiagnoses may be due to failure to detect (hypo)manic symptoms, or it may reflect the true lack of manifestation of prototypical symptoms necessary to make the diagnosis. In either scenario, however, individuals may receive treatments which are suboptimal for the treatment of BD, and may be associated with more frequent and severe episodes, an increased rate of comorbidities, and a higher risk of suicide attempts (Perlis et al., 2004).

While various disorders may precede BD, most studies have focused on risk factors when the initial presentation is depression (Musliner and Østergaard, 2018; Rhee et al., 2023). Studies utilizing nationwide registries have found a broad range of conversion rates in those initially diagnosed with MDD, ranging from 5.8 % over 13 years in the Swedish registry (Rhee et al., 2023), to 8.4 % over 7.7 years in the Danish registry(Musliner and Østergaard, 2018), and a high estimate rate of 19 % during a 10 year period in the Taiwan National Health Insurance Research Database (Hu et al., 2020). Systematic reviews, with additional longitudinal studies from clinical samples, have similarly found average conversion rates to vary from 12.9 % (Kessing et al., 2017) to 22.5 % (Ratheesh et al., 2017). Despite the variation in transition rates, these studies have generally observed only minor differences between the sexes, but have found several factors associated with an elevated risk of conversion, including a family history of bipolar disorder (BD), the presence of more severe and/or psychotic symptoms during depressive episodes, suicidal ideation or behaviors, treatment with mood stabilizers, and care in inpatient facilities (for example, Tondo et al., 2024).

However, a substantial proportion of patients who are ultimately diagnosed with BD may initially receive a diagnosis of anxiety (Goes, 2015) and/or attentional and behavioral disorders (Brancati et al., 2021). Although these disorders have less symptomatic overlap with BD, they have been fount to frequently precede the diagnosis of BD in both high-risk (Duffy et al., 2019) and epidemiological studies (Faedda et al., 2019), highlighting the importance of studying a broader set of disorders to comprehensively identify individuals at risk of converting to BD.

Most research on attention-deficit/hyperactivity disorder (ADHD), as either a precursor and a comorbid condition, has focused on childhood and adolescent age groups, where systematic reviews report conversion rates of approximately one in 10 individuals (Brancati et al., 2021). However, ADHD is also increasingly being diagnosed in adults (Schiweck et al., 2021), where its role as a precursor diagnosis to BD has received less attention. Like other comorbidities, the presence of ADHD may contribute to worse overall outcome (Pinna et al., 2019). Anxiety disorders have similarly been studied as “risk factors” for the development of later BD in children and young adults (Buckley et al., 2023). While there is a high rate of “comorbidity” between BD and anxiety disorders, this phenomenon may be representative of a broader BD phenotype rather than distinct illnesses (Vázquez et al., 2014). In studies of high-risk offspring of parents with BD, anxiety disorders are among the most common initial manifestation of psychopathology, reflecting a heterogeneous but prognostically important comorbid disorder once BD is diagnosed.

Importantly, all of these prodromal disorders are treated with pharmacological options contraindicated as monotherapy in BD, underscoring the importance of early identification of patients who ultimately develop a bipolar spectrum illness and may benefit from alternative therapeutic approaches. While it is well known that these diagnoses often precede the diagnosis of BD, previous studies have focused on a single diagnosis at a time or a limited age ranges. This has limited their utility compared with more comprehensive models that consider the broader array of diagnoses and comorbidity patterns encountered in clinical practice. To address this gap, our study utilized data from routine clinical care across all age groups within a diverse healthcare system to conduct analyses of MDD, anxiety disorders, and ADHD as potential precursors and risk factors for developing a later diagnosis of BD.