An Investigation of Psychosis Subgroups With Prognostic Validation and Exploration of Genetic Underpinnings: The PsyCourse Study

IMPORTANCE

Identifying psychosis subgroups could improve clinical and research precision. Research has focused on symptom subgroups, but there is a need to consider a broader clinical spectrum, disentangle illness trajectories, and investigate genetic associations.

OBJECTIVE

To detect psychosis subgroups using data-driven methods and examine their illness courses over 1.5 years and polygenic scores for schizophrenia, bipolar disorder, major depression disorder, and educational achievement.

DESIGN, SETTING, AND PARTICIPANTS

This ongoing multisite, naturalistic, longitudinal (6-month intervals) cohort study began in January 2012 across 18 sites. Data from a referred sample of 1223 individuals (765 in the discovery sample and 458 in the validation sample) with DSM-IV diagnoses of schizophrenia, bipolar affective disorder (I/II), schizoaffective disorder, schizophreniform disorder, and brief psychotic disorder were collected from secondary and tertiary care sites. Discovery data were extracted in September 2016 and analyzed from November 2016 to January 2018, and prospective validation data were extracted in October 2018 and analyzed from January to May 2019.

MAIN OUTCOMES AND MEASURES

A clinical battery of 188 variables measuring demographic characteristics, clinical history, symptoms, functioning, and cognition was decomposed using nonnegative matrix factorization clustering. Subtype-specific illness courses were compared with mixed models and polygenic scores with analysis of covariance. Supervised learning was used to replicate results in validation data with the most reliably discriminative 45 variables.

RESULTS

Of the 765 individuals in the discovery sample, 341 (44.6%) were women, and the mean (SD) age was 42.7 (12.9) years. Five subgroups were found and labeled as affective psychosis (n = 252), suicidal psychosis (n = 44), depressive psychosis (n = 131), high-functioning psychosis (n = 252), and severe psychosis (n = 86). Illness courses with significant quadratic interaction terms were found for psychosis symptoms (R2 = 0.41; 95% CI, 0.38-0.44), depression symptoms (R2 = 0.28; 95% CI, 0.25-0.32), global functioning (R2 = 0.16; 95% CI, 0.14-0.20), and quality of life (R2 = 0.20; 95% CI, 0.17-0.23). The depressive and severe psychosis subgroups exhibited the lowest functioning and quadratic illness courses with partial recovery followed by reoccurrence of severe illness. Differences were found for educational attainment polygenic scores (mean [SD] partial η2 = 0.014 [0.003]) but not for diagnostic polygenic risk. Results were largely replicated in the validation cohort.

CONCLUSIONS AND RELEVANCE

Psychosis subgroups were detected with distinctive clinical signatures and illness courses and specificity for a nondiagnostic genetic marker. New data-driven clinical approaches are important for future psychosis taxonomies. The findings suggest a need to consider short-term to medium-term service provision to restore functioning in patients stratified into the depressive and severe psychosis subgroups.

The role of environmental stress and DNA methylation in the longitudinal course of bipolar disorder

BACKGROUND

Stressful life events influence the course of affective disorders, however, the mechanisms by which they bring about phenotypic change are not entirely known.

METHODS

We explored the role of DNA methylation in response to recent stressful life events in a cohort of bipolar patients from the longitudinal PsyCourse study (n = 96). Peripheral blood DNA methylomes were profiled at two time points for over 850,000 methylation sites. The association between impact ratings of stressful life events and DNA methylation was assessed, first by interrogating methylation sites in the vicinity of candidate genes previously implicated in the stress response and, second, by conducting an exploratory epigenome-wide association analysis. Third, the association between epigenetic aging and change in stress and symptom measures over time was investigated.

RESULTS

Investigation of methylation signatures over time revealed just over half of the CpG sites tested had an absolute difference in methylation of at least 1% over a 1-year period. Although not a single CpG site withstood correction for multiple testing, methylation at one site (cg15212455) was suggestively associated with stressful life events (p < 1.0 × 10^-5). Epigenetic aging over a 1-year period was not associated with changes in stress or symptom measures.

CONCLUSIONS

To the best of our knowledge, our study is the first to investigate epigenome-wide methylation across time in bipolar patients and in relation to recent, non-traumatic stressful life events. Limited and inconclusive evidence warrants future longitudinal investigations in larger samples of well-characterized bipolar patients to give a complete picture regarding the role of DNA methylation in the course of bipolar disorder.

The genetic relationship between educational attainment and cognitive performance in major psychiatric disorders

Cognitive deficits are a core feature of psychiatric disorders like schizophrenia and bipolar disorder. Evidence supports a genome-wide polygenic score (GPS) for educational attainment (GPSEDU) can be used to explain variability in cognitive performance. We aimed to identify different cognitive domains associated with GPSEDU in a transdiagnostic clinical cohort of chronic psychiatric patients with known cognitive deficits. Bipolar and schizophrenia patients from the PsyCourse cohort (N = 730; 43% female) were used. Likewise, we tested whether GPSs for schizophrenia (GPSSZ) and bipolar disorder (GPSBD) were associated with cognitive outcomes. GPSEDU explained 1.5% of variance in the backward verbal digit span, 1.9% in the number of correctly recalled words of the Verbal Learning and Memory Test, and 1.1% in crystallized intelligence. These effects were robust to the influences of treatment and diagnosis. No significant associations between GPSSZ or GPSBD with cognitive outcomes were found. Furthermore, these risk scores did not confound the effect of GPSEDU on cognitive outcomes. GPSEDU explains a small fraction of cognitive performance in adults with psychiatric disorders, specifically for domains related to linguistic learning and working memory. Investigating such a proxy-phenotype longitudinally, could give intriguing insight into the disease course, highlighting at what time genes play a more influential role on cognitive performance. Better understanding the origin of these deficits might help identify those patients at risk for lower levels of functioning and poor social outcomes. Polygenic estimates may in the future be part of predictive models for more personalized interventions.

The influence of religious activity and polygenic schizophrenia risk on religious delusions in schizophrenia

BACKGROUND

Religious delusions are a common symptom in patients experiencing psychosis, with varying prevalence rates of religious delusions across cultures and societies. To enhance our knowledge of this distinct psychotic feature, we investigated the mutually-adjusted association of genetic and environmental factors with occurrence of religious delusions.

METHODS

We studied 262 adult German patients with schizophrenia or schizoaffective disorder. Association with lifetime occurrence of religious delusions was tested by multiple logistic regression for the following putative predictors: self-reported degree of religious activity, DSM-IV diagnosis, sex, age, education level, marital status, presence of acute delusion at the time of interview and an individual polygenic schizophrenia-risk score (SZ-PRS, available in 239 subjects).

RESULTS

Of the 262 patients, 101 (39%) had experienced religious delusions. The risk of experiencing religious delusions was significantly increased in patients with strong religious activity compared to patients without religious affiliation (OR = 3.6, p = 0.010). Low or moderate religious activity had no significant effect. The same analysis including the SZ-PRS confirmed the effect of high religious activity on occurrence of religious delusions (OR = 4.1, p = 0.008). Additionally, the risk of experiencing religious delusions increased with higher SZ-PRS (OR 1.4, p = 0.020, using pT = 0.05 for SZ-PRS calculation). None of the other variables were significantly associated with lifetime occurrence of religious delusions.

CONCLUSIONS

Our results suggest that strong religious activity and high SZ-PRS are independent risk factors for the occurrence of religious delusions in schizophrenia and schizoaffective disorder.

A longitudinal approach to biological psychiatric research: The PsyCourse study

In current diagnostic systems, schizophrenia and bipolar disorder are still conceptualized as distinct categorical entities. Recently, both clinical and genomic evidence have challenged this Kraepelinian dichotomy. There are only few longitudinal studies addressing potential overlaps between these conditions. Here, we present design and first results of the PsyCourse study (N = 891 individuals at baseline), an ongoing transdiagnostic study of the affective-to-psychotic continuum that combines longitudinal deep phenotyping and dimensional assessment of psychopathology with an extensive collection of biomaterial. To provide an initial characterization of the PsyCourse study sample, we compare two broad diagnostic groups defined by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) classification system, that is, predominantly affective (n = 367 individuals) versus predominantly psychotic disorders (n = 524 individuals). Depressive, manic, and psychotic symptoms as well as global functioning over time were contrasted using linear mixed models. Furthermore, we explored the effects of polygenic risk scores for schizophrenia on diagnostic group membership and addressed their effects on nonparticipation in follow-up visits. While phenotypic results confirmed expected differences in current psychotic symptoms and global functioning, both manic and depressive symptoms did not vary between both groups after correction for multiple testing. Polygenic risk scores for schizophrenia significantly explained part of the variability of diagnostic group. The PsyCourse study presents a unique resource to research the complex relationships of psychopathology and biology in severe mental disorders not confined to traditional diagnostic boundaries and is open for collaborations.

Investigating polygenic burden in age at disease onset in bipolar disorder: Findings from an international multicentric study

OBJECTIVES

Bipolar disorder (BD) with early disease onset is associated with an unfavorable clinical outcome and constitutes a clinically and biologically homogenous subgroup within the heterogeneous BD spectrum. Previous studies have found an accumulation of early age at onset (AAO) in BD families and have therefore hypothesized that there is a larger genetic contribution to the early-onset cases than to late onset BD. To investigate the genetic background of this subphenotype, we evaluated whether an increased polygenic burden of BD- and schizophrenia (SCZ)-associated risk variants is associated with an earlier AAO in BD patients.

METHODS

A total of 1995 BD type 1 patients from the Consortium of Lithium Genetics (ConLiGen), PsyCourse and Bonn-Mannheim samples were genotyped and their BD and SCZ polygenic risk scores (PRSs) were calculated using the summary statistics of the Psychiatric Genomics Consortium as a training data set. AAO was either separated into onset groups of clinical interest (childhood and adolescence [≤18 years] vs adulthood [>18 years]) or considered as a continuous measure. The associations between BD- and SCZ-PRSs and AAO were evaluated with regression models.

RESULTS

BD- and SCZ-PRSs were not significantly associated with age at disease onset. Results remained the same when analyses were stratified by site of recruitment.

CONCLUSIONS

The current study is the largest conducted so far to investigate the association between the cumulative BD and SCZ polygenic risk and AAO in BD patients. The reported negative results suggest that such a polygenic influence, if there is any, is not large, and highlight the importance of conducting further, larger scale studies to obtain more information on the genetic architecture of this clinically relevant phenotype.

Flexible 3D laparoscopic assisted reduction and percutaneous fixation of acetabular fractures: Introduction to a new surgical option

The gold standard for fractures of the acetabulum is to perform an open reduction and internal fixation in order to achieve anatomical reduction. In a well-defined subset of patients, percutaneous techniques may be employed but achieving reduction by closed means can be challenging especially for fractures with large degrees of displacement. Such patient may include elderly patients who may not have the physiologic reserve to withstand open approaches. In our paper, we present a new option using laparoscopic assisted reduction of the acetabular fracture and percutaneous fixation. The young obese patient refused all forms of blood products transfusion and presented with a displaced transverse posterior wall fracture. While we do not recommend routine use of such technique and recognize its numerous limitations, we present it as an alternative strategy in a small subset of patients.

Agonist high and low affinity state ratios predict drug intrinsic activity and a revised ternary complex mechanism at serotonin 5-HT(2A) and 5-HT(2C) receptors

The ternary complex model as applied to G-protein coupled receptors (GPCR) predicts that an agonist binds with low affinity (K(L)) to the free receptor (R), leading to an agonist/receptor/G-protein complex. This ternary complex displays high agonist affinity (K(H)), resulting in signal transduction. Classical dogma states that the ratio K(L)/K(H) predicts intrinsic activity of drugs: the higher the ratio the higher the intrinsic activity. This model was based on studies in which K(L) and K(H) were indirectly determined by computer analyses of antagonist radioligand binding data. In order to investigate the relationship of K(L), K(H), and intrinsic activity for agonists at 5-HT(2A) and 5-HT(2C) receptors, we utilized (3)H-agonist and (3)H-antagonist radioligands to directly determine K(H) and K(L). Comparisons of the log K(L)/K(H) ratios and intrinsic activities of drugs for stimulating intracellular phosphatidylinositol (PI) hydrolysis revealed a strong correlation for 5-HT(2A) (r(2) = 0.92) and 5-HT(2C) (r(2) = 0.96) receptors. The data were fit to computer simulations based on the original ternary complex model and the revised ternary complex model in which an activated state of the receptor (R*) exists in equilibrium with the resting state of the receptor (R). Data produced for both 5-HT(2A) and 5-HT(2C) receptors were better-fitted to a revised ternary complex model, rather than the classical ternary complex model. These data support a revised model for the molecular events coupling GPCR to activation of G-proteins and indicate that a strong correlation between the K(L)/K(H) ratio and intrinsic activity for agonist action at GPCR is consistent with the existence of R*.

The physiological costs of box lifting

Thirteen male subjects lifted boxes of three different weights for 20 min periods each. Ventilation, oxygen uptake and heart rates were measured. Each subject made subjective estimates of the degree of difficulty of the work he was doing. Oxygen uptake and ventilation were found to reach steady state after about four minutes and remain there for the rest of the work session. Heart rate for the two lighter boxes reached steady state after about thirteen minutes while the heart rate continued to rise when lifting was done with the heaviest box. The relationships between oxygen uptake, heart rate and work load tended to be curvilinear, whereas the ventilation was linear when compared to work load. The heart rate and oxygen uptake relationship was also curvilinear, while ventilation and oxygen uptake had a linear relationship. The subjective ratings were expected to be about one-tenth of the heart rate. Only the ratings made while lifting the lightest box reflected this. The heavier boxes were rated as being more difficult to lift than 10 times the heart rate per minute. The mechanical efficiencies were found to range between 4.4% and 6.2%.