Response to lithium in patients with bipolar disorder is associated with clinical and transdiagnostic genetic factors. The predictive combination of these variables might help clinicians better predict which patients will respond to lithium treatment.

To use a combination of transdiagnostic genetic and clinical factors to predict lithium response in patients with bipolar disorder.

This study utilised genetic and clinical data (n = 1034) collected as part of the International Consortium on Lithium Genetics (ConLi+Gen) project. Polygenic risk scores (PRS) were computed for schizophrenia and major depressive disorder, and then combined with clinical variables using a cross-validated machine-learning regression approach. Unimodal, multimodal and genetically stratified models were trained and validated using ridge, elastic net and random forest regression on 692 patients with bipolar disorder from ten study sites using leave-site-out cross-validation. All models were then tested on an independent test set of 342 patients. The best performing models were then tested in a classification framework.

The best performing linear model explained 5.1% (P = 0.0001) of variance in lithium response and was composed of clinical variables, PRS variables and interaction terms between them. The best performing non-linear model used only clinical variables and explained 8.1% (P = 0.0001) of variance in lithium response. A priori genomic stratification improved non-linear model performance to 13.7% (P = 0.0001) and improved the binary classification of lithium response. This model stratified patients based on their meta-polygenic loadings for major depressive disorder and schizophrenia and was then trained using clinical data.

Using PRS to first stratify patients genetically and then train machine-learning models with clinical predictors led to large improvements in lithium response prediction. When used with other PRS and biological markers in the future this approach may help inform which patients are most likely to respond to lithium treatment.

Studying phenotypic and genetic characteristics of age at onset (AAO) and polarity at onset (PAO) in bipolar disorder can provide new insights into disease pathology and facilitate the development of screening tools.

To examine the genetic architecture of AAO and PAO and their association with bipolar disorder disease characteristics.

Genome-wide association studies (GWASs) and polygenic score (PGS) analyses of AAO (n = 12 977) and PAO (n = 6773) were conducted in patients with bipolar disorder from 34 cohorts and a replication sample (n = 2237). The association of onset with disease characteristics was investigated in two of these cohorts.

Earlier AAO was associated with a higher probability of psychotic symptoms, suicidality, lower educational attainment, not living together and fewer episodes. Depressive onset correlated with suicidality and manic onset correlated with delusions and manic episodes. Systematic differences in AAO between cohorts and continents of origin were observed. This was also reflected in single-nucleotide variant-based heritability estimates, with higher heritabilities for stricter onset definitions. Increased PGS for autism spectrum disorder (β = −0.34 years, s.e. = 0.08), major depression (β = −0.34 years, s.e. = 0.08), schizophrenia (β = −0.39 years, s.e. = 0.08), and educational attainment (β = −0.31 years, s.e. = 0.08) were associated with an earlier AAO. The AAO GWAS identified one significant locus, but this finding did not replicate. Neither GWAS nor PGS analyses yielded significant associations with PAO.

AAO and PAO are associated with indicators of bipolar disorder severity. Individuals with an earlier onset show an increased polygenic liability for a broad spectrum of psychiatric traits. Systematic differences in AAO across cohorts, continents and phenotype definitions introduce significant heterogeneity, affecting analyses.

This poster aims to examine the impact of social cognitive deficits on psychosocial functioning in depressed patients, as well as summarise the utility of various evidence-based therapeutic interventions employed to target these deficits. The stated hypotheses were twofold: (1) that social cognitive impairment in major depressive disorder will correlate with poorer psychosocial functioning; and (2) that these deficits will respond to existing anti-depressant therapies.

Social cognition is an important adaptive trait that incorporates the identification, perception and interpretation of socially relevant information from the external world. It is frequently affected in major depressive disorder such that depressed patien

A review of the existing literature was performed in order to test the stated hypotheses. Pertinent sources were identified via the MEDLINE, EMBASE, PsycINFO, PubMed, Scopus and Google Scholar databases. A total of 107 studies met inclusion criteria for review.

Impaired social cognitive performance in depressed patients correlated with poorer psychosocial functioning across the key domains of general cognitive functioning and quality of life. Many current anti-depressant therapies were found to have a normalising effect on the social cognitive abilities of depressed subjects, both at a neural and functional level. Anti-depressant medications, in particular citalopram and reboxetine, appeared to correct facial affect recognition deficits, while a psychotherapeutic approach demonstrated improvements in theory of mind and negative interpretive bias. Data relating to other common treatments, such as electroconvulsive therapy, are limited.

The impact and treatment of social cognitive deficits in major depressive disorder is an important emerging field. The social cognitive deficits evident in depressed patients are sometimes subtle, but afford a significant functional impact. Additionally, it appears these impairments are at least partially reversible using anti-depressants or psychotherapy.