Clinical predictors of conversion to bipolar disorder in a prospective longitudinal familial high-risk sample: focus on depressive features

Child and adolescent anxiety as a risk factor for bipolar disorder: A systematic review of longitudinal studies

OBJECTIVES

Several studies have suggested that anxiety disorders in childhood and adolescence often precede the onset of bipolar disorder. We therefore systematically reviewed the relationship between child and adolescent anxiety and later bipolar disorder.

METHODS

Online databases (Medline [for Ovid], EMBASE and PsychINFO) were searched for original, peer-reviewed studies examining the relationship between child and adolescent anxiety and later bipolar disorder. Studies in both community samples and bipolar offspring samples were included.

RESULTS

A total of 16 studies were included in the review. The results were broadly consistent and revealed that child and adolescent anxiety disorders are associated with later bipolar disorder in community samples. In bipolar offspring, child and adolescent anxiety disorders are a marker of increased risk and predict the onset of bipolar disorder and other major mood disorders.

CONCLUSIONS

There is evidence that anxiety disorders in childhood and adolescence increase the risk of later bipolar disorder. Anxiety disorders may be a useful target for early intervention in those at high-risk of bipolar disorder.

Epigenetic signatures relating to disease-associated genotypic burden in familial risk of bipolar disorder

Environmental factors contribute to risk of bipolar disorder (BD), but how environmental factors impact the development of psychopathology within the context of elevated genetic risk is unknown. We herein sought to identify epigenetic signatures operating in the context of polygenic risk for BD in young people at high familial risk (HR) of BD. Peripheral blood-derived DNA was assayed using Illumina PsychArray, and Methylation-450K or -EPIC BeadChips. Polygenic risk scores (PRS) were calculated using summary statistics from recent genome-wide association studies for BD, major depressive disorder (MDD) and cross-disorder (meta-analysis of eight psychiatric disorders). Unrelated HR participants of European ancestry (n = 103) were stratified based on their BD-PRS score within the HR-population distribution, and the top two quintiles (High-BD-PRS; n = 41) compared against the bottom two quintiles (Low-BD-PRS; n = 41). The High-BD-PRS stratum also had higher mean cross-disorder-PRS and MDD-PRS (ANCOVA p = 0.035 and p = 0.024, respectively). We evaluated DNA methylation differences between High-BD-PRS and Low-BD-PRS strata using linear models. One differentially methylated probe (DMP) (cg00933603; p = 3.54 × 10-7) in VARS2, a mitochondrial aminoacyl-tRNA synthetase, remained significantly hypomethylated after multiple-testing correction. Overall, BD-PRS appeared to broadly impact epigenetic processes, with 1,183 genes mapped to nominal DMPs (p < 0.05); these displayed convergence with genes previously associated with BD, schizophrenia, chronotype, and risk taking. We tested poly-methylomic epigenetic profiles derived from nominal DMPs in two independent samples (n = 54 and n = 82, respectively), and conducted an exploratory evaluation of the effects of family environment, indexing cohesion and flexibility. This study highlights an important interplay between heritable risk and epigenetic factors, which warrant further exploration.

Transitioning to bipolar disorder: A systematic review of prospective high-risk studies

PURPOSE OF REVIEW

Bipolar disorder is a highly heritable condition, which can progress from an asymptomatic period in at-risk individuals to a potentially debilitating illness. Identifying individuals who are at a high risk of developing bipolar disorder may provide an opportunity for early intervention to improve outcomes. The main objective of this systematic review is to provide an overview of prospective studies that evaluated the incidence and predictors of transitioning to bipolar disorder among high-risk individuals.

RECENT FINDINGS

Twenty-three publications from 16 cohorts were included in the final review. Most studies focused on familial high-risk groups, while others either used clinical or a combination of clinical and genetic risk factors. The follow-up length was from 1 to 21 years and the rate of conversion to bipolar disorder was between 8 and 25% among different studies. Overall, the results suggest that a combination of genetic and clinical risk factors; namely, subthreshold (hypo)manic symptoms and elevated depressive symptoms, may be required to optimally predict conversion to bipolar disorder.

SUMMARY

The concept of high-risk for bipolar disorder is still in its infancy. Further discussions are needed to work towards an expert consensus on the high-risk criteria for bipolar disorder, taking into account both clinical and genetic risk factors.

Predictors of diagnostic transition from major depressive disorder to bipolar disorder: a retrospective observational network study

Many patients with bipolar disorder (BD) are initially misdiagnosed with major depressive disorder (MDD) and are treated with antidepressants, whose potential iatrogenic effects are widely discussed. It is unknown whether MDD is a comorbidity of BD or its earlier stage, and no consensus exists on individual conversion predictors, delaying BD's timely recognition and treatment. We aimed to build a predictive model of MDD to BD conversion and to validate it across a multi-national network of patient databases using the standardization afforded by the Observational Medical Outcomes Partnership (OMOP) common data model. Five "training" US databases were retrospectively analyzed: IBM MarketScan CCAE, MDCR, MDCD, Optum EHR, and Optum Claims. Cyclops regularized logistic regression models were developed on one-year MDD-BD conversion with all standard covariates from the HADES PatientLevelPrediction package. Time-to-conversion Kaplan-Meier analysis was performed up to a decade after MDD, stratified by model-estimated risk. External validation of the final prediction model was performed across 9 patient record databases within the Observational Health Data Sciences and Informatics (OHDSI) network internationally. The model's area under the curve (AUC) varied 0.633-0.745 (µ = 0.689) across the five US training databases. Nine variables predicted one-year MDD-BD transition. Factors that increased risk were: younger age, severe depression, psychosis, anxiety, substance misuse, self-harm thoughts/actions, and prior mental disorder. AUCs of the validation datasets ranged 0.570-0.785 (µ = 0.664). An assessment algorithm was built for MDD to BD conversion that allows distinguishing as much as 100-fold risk differences among patients and validates well across multiple international data sources.

Substance use as a risk factor for bipolar disorder: A systematic review

Detecting substance use as a predictor of bipolar disorder (BD) is important for clinicians to perform accurate and early diagnosis, as well as better manage the treatment of individuals with BD. The aim of this systematic review was to describe whether substance use is a predictor of BD. A literature search was conducted using the following databases: PubMed, PsycINFO, and Embase. All eligible studies published up to February 9, 2021 were included. This systematic review included 22 studies. We found that 66.7% of the studies assessing overall substance use found that overall substance use was a risk factor for BD. Regarding the specific substances assessed, cannabis use was described as a risk factor for BD in 55.6% of the studies, nonmedical use of prescription medications was a risk factor for BD in 50% of the studies, nicotine was found as a risk factor for BD in 50% of the studies, and alcohol use was described as a risk factor for BD in 42.9% of the studies assessing it. Only one study assessed whether cocaine use was a risk factor for BD and found a significant association. Interestingly, some studies suggested that the greater frequency of cannabis use was associated with greater risk to develop BD or hypomanic/manic symptoms. In conclusion, there is evidence supporting that substance use is a risk factor for BD. Importantly, when assessing the risk factors for BD related to psychoactive substance use, special attention should be given for the frequency of cannabis use.

Discriminating bipolar depression from major depressive disorder with polygenic risk scores

BACKGROUND

Although accurate differentiation between bipolar disorder (BD) and unipolar major depressive disorder (MDD) has important prognostic and therapeutic implications, the distinction is often challenging based on clinical grounds alone. In this study, we tested whether psychiatric polygenic risk scores (PRSs) improve clinically based classification models of BD v. MDD diagnosis.

METHODS

Our sample included 843 BD and 930 MDD subjects similarly genotyped and phenotyped using the same standardized interview. We performed multivariate modeling and receiver operating characteristic analysis, testing the incremental effect of PRSs on a baseline model with clinical symptoms and features known to associate with BD compared with MDD status.

RESULTS

We found a strong association between a BD diagnosis and PRSs drawn from BD (R2 = 3.5%, p = 4.94 × 10-12) and schizophrenia (R2 = 3.2%, p = 5.71 × 10-11) genome-wide association meta-analyses. Individuals with top decile BD PRS had a significantly increased risk for BD v. MDD compared with those in the lowest decile (odds ratio 3.39, confidence interval 2.19-5.25). PRSs discriminated BD v. MDD to a degree comparable with many individual symptoms and clinical features previously shown to associate with BD. When compared with the full composite model with all symptoms and clinical features PRSs provided modestly improved discriminatory ability (ΔC = 0.011, p = 6.48 × 10-4).

CONCLUSIONS

Our study demonstrates that psychiatric PRSs provide modest independent discrimination between BD and MDD cases, suggesting that PRSs could ultimately have utility in subjects at the extremes of the distribution and/or subjects for whom clinical symptoms are poorly measured or yet to manifest.

Predictors of conversion from major depressive disorder to bipolar disorder

The present study has two main aims: (1) To assess whether childhood trauma helps to differentiate Major Depressive Disorder (MDD) from Bipolar Disorder (BD) in a cross-sectional design; and (2) Describe the rate of conversion from MDD to BD, as well as the clinical and demographic predictors of conversion from MDD to BD in a prospective cohort design. We conducted a prospective cohort study in two phases, in the city of Pelotas, RS, Brazil. In the first phase, 565 subjects diagnosed with MDD, and 127 with BD according to the Mini International Neuropsychiatric Interview were included. In the second phase, only individuals with MDD were reevaluated for potential conversion to BD. The rate of conversion from MDD to BD in 3 years was 12.4%. Predictors of conversion from MDD to BD included lower educational level, use of illicit substances, younger age of the first depressive episode, and family history of BD. Childhood trauma was not a significant risk factor for conversion to BD in our prospective study. Our findings can contribute to the prevention and identification of conversion from MDD to BD, as well as to the establishment of more targeted therapeutic interventions, improving the prognosis of these individuals.

Early intervention for people at high risk of developing bipolar disorder: a systematic review of clinical trials

Early intervention approaches are built on the premise of preventing disability, burden, and cognitive sequelae caused by bipolar disorder. The objective of this systematic review was to characterise the effectiveness of all the available psychological and pharmacological treatments for early intervention in people at high risk of developing bipolar disorder. The study was registered with PROSPERO (CRD42019133420). We did a systematic search to identify studies published in ten databases up to March 27, 2020. Randomised controlled trials and cohort studies that assessed the effect of pharmacological or psychological interventions in people at high risk of developing bipolar disorder were included. Studies of first episodes of mania were excluded. Eligible papers were assessed for quality and data were extracted. The primary outcomes were change in manic and depressive symptoms from baseline to endpoint. Of the 2856 citations retrieved by our search, 16 studies were included; five evaluated pharmacotherapeutic strategies (three randomised controlled trials and two open-label studies), ten assessed psychotherapeutic strategies (four randomised controlled trials and six open-label studies), and one randomised controlled trial assessed combination therapy; these 16 trials included a total of 755 participants at high risk of developing bipolar disorder. Quality assessment indicated fair to good quality for open-label studies, and a high risk of bias in four randomised controlled trials. Among the pharmacotherapeutic interventions, there is preliminary support for the efficacy of aripiprazole in reducing mood symptoms in people at high risk of developing bipolar disorder. Psychological interventions were effective for various outcomes. There was substantial methodological heterogeneity across studies. This systematic review underscores the need for multicentre, prospective, methodologically homogeneous studies evaluating conversion to bipolar disorder as an outcome measure.

Expanding the search for emerging mental ill health to safeguard student potential and vocational success in high school: A narrative review

AIM

Young people experiencing mental ill health are more likely than their healthy aged peers to drop out of high school. This can result in social exclusion and vocational derailment. Identifying young people at risk and taking action before an illness is established or school dropout occurs is an important goal. This study aimed to examine evidence for the risk markers and at risk mental states of the clinical staging model (stage 0-1b) and whether these risk states and early symptoms impact school participation and academic attainment.

METHOD

This narrative review assembles research from both the psychiatry and education literature. It examines stage 0 to stage 1b of the clinical staging model and links the risk states and early symptoms to evidence about the academic success of young people in high school.

RESULTS

In accordance with the clinical staging model and evidence from education literature, childhood trauma and parental mental illness can impact school engagement and academic progress. Sleep disturbance can result in academic failure. Undifferentiated depression and anxiety can increase the risk for school dropout. Subthreshold psychosis and hypomanic states are associated with functional impairment and high rates of Not in Employment, Education, or Training (NEET) but are not recognized in the education literature.

CONCLUSION

Risk markers for emerging mental ill health can be identified in education research and demonstrate an impact on a student's success in high school. Clear referral protocols need to be embedded into school life to reduce risk of progression to later stages of illness and support school participation and success.

Aberrant structural covariance networks in youth at high familial risk for mood disorder

OBJECTIVES

Current research suggests significant disruptions in functional brain networks in individuals with mood disorder, and in those at familial risk. Studies of structural brain networks provide important insights into synchronized maturational change but have received less attention. We aimed to investigate developmental relationships of large-scale brain networks in mood disorder using structural covariance (SC) analyses.

METHODS

We conducted SC analysis of baseline structural imaging data from 121 at the time of scanning unaffected high risk (HR) individuals (29 later developed mood disorder after a median time of 4.95 years), and 89 healthy controls (C-well) with no familial risk from the Scottish Bipolar Family Study (age 15-27, 64% female). Voxel-wise analyses of covariance were conducted to compare the associations between each seed region in visual, auditory, motor, speech, semantic, executive-control, salience and default-mode networks and the whole brain signal. SC maps were compared for (a) HR(all) versus C-well individuals, and (b) between those who remained well (HR-well), versus those who subsequently developed mood disorder (HR-MD), and C-well.

RESULTS

There were no significant differences between HR(all) and C-well individuals. On splitting the HR group based on subsequent clinical outcome, the HR-MD group however displayed greater baseline SC in the salience and executive-control network, and HR-well individuals showed less SC in the salience network, compared to C-well, respectively (P < .001).

CONCLUSIONS

These findings indicate differences in network-level inter-regional relationships, especially within the salience network, which precede onset of mood disorder in those at familial risk.

Psychological interventions for young people at risk for bipolar disorder: A systematic review

OBJECTIVES

Several studies have recently been conducted that have explored the benefits of psychological interventions in reducing symptomatology or improving outcomes in young people at-risk of developing bipolar disorder. The aim of this review was to explore if such interventions reduce current psychiatric symptoms and prevent the development of new symptoms.

METHODS

A systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Databases searched were MEDLINE, EMBASE, PsychInfo, CINAHL and SCOPUS from January 1990 until August 2018. The inclusion criteria were young people aged under 30 years with a family history of bipolar disorder and any empirical studies that contained a psychological or psychoeducation intervention.

RESULTS

A total of 7 articles (N = 138, 55 males) were included (mean age ranged from 12 to 15 years). Interventions conducted included Family Focussed Therapy, Interpersonal and Social Rhythm Therapy, and Mindfulness-based Cognitive Therapy for Children. Significant results were found in some studies, depending on the sample's initial symptoms, with reduced time to relapse and reduced symptoms of anxiety, depression and hypo/mania being found.

LIMITATIONS

No studies have explored if interventions may delay the time to onset of first hypo/manic episodes and only two randomised controlled trials were identified.

CONCLUSIONS

Some significant results were noted with lower symptoms of anxiety, depression and hypo/mania being found in some studies. It is currently unclear if psychological interventions may prevent the development of bipolar disorder or other psychiatric symptoms over time; further longitudinal studies are required.

Physical activity is associated with left corticospinal tract microstructure in bipolar depression

Psychomotor retardation and reduced daily activities are core features of the depressive syndrome including bipolar disorder (BD). It was the aim of this study to investigate white matter microstructure of the motor system in BD during depression and its association with motor activity. We hypothesized reduced physical activity, microstructural alterations of motor tracts and different associations between activity levels and motor tract microstructure in BD. Nineteen bipolar patients with a current depressive episode (BD) and 19 healthy controls (HC) underwent diffusion weighted magnetic resonance imaging (DW-MRI)-scans. Quantitative motor activity was assessed with 24 h actigraphy recordings. Bilateral corticospinal tracts (CST), interhemispheric connections between the primary motor cortices (M1) and between the pre-supplementary motor areas (pre-SMA) were reconstructed individually based on anatomical landmarks using Diffusion Tensor Imaging (DTI) based tractography. Mean fractional anisotropy (FA) was sampled along the tracts. To enhance specificity of putative findings a segment of the optic radiation was reconstructed as comparison tract. Analyses were complemented with Tract Based Spatial Statistics (TBSS) analyses. BD had lower activity levels (AL). There was a sole increase of fractional anisotropy (FA) in BD in the left CST. Further, there was a significant group x AL interaction for FA of the left CST pointing to a selective positive association between FA and AL in BD. The comparison tract and TBSS analyses did not detect significant group differences. Our results point to white matter microstructure alterations of the left CST in BD. The positive association between motor activity and white matter microstructure suggests a compensatory role of the left CST for psychomotor retardation in BD.

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Daily physical activity is reduced in bipolar patients with a current depressive episode (BD)

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The left corticospinal tract (CST) in BD shows increased fractional anisotropy (FA)

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Increases of FA in the left corticospinal tract in BD are related to less pronounced psychomotor retardation