Why do indiviuals with schizophrenia drop out of observational clinical trials?

Measuring recovery in participants with a schizophrenia spectrum disorder: validation of the Individual Recovery Outcomes Counter (I.ROC)

BACKGROUND

To improve recovery in mental health, validated instruments are needed.

AIMS

This study evaluates psychometric properties of the Individual Recovery Outcomes Counter (I.ROC) in a Dutch population of participants with a schizophrenia spectrum disorder (SSD).

METHODS

326 participants completed the I.ROC at baseline (n = 326), six months (n = 155) and twelve months (n = 84) as part of a routine outcome assessment. Reliability, validity, sensitivity to change, and internal factor structure were examined.

RESULTS

Participants evaluated the I.ROC as comprehensive. Internal consistency of the I.ROC (α = 0.88) and test-retest reliability (r = .85, p < .001) are good. Negative moderate correlations with the total score of the PANSS (r=-.50, p < .001) and the HoNOS (r=-.52, p < .001) were found, and a small negative correlation with the FR tool (r=-.36, p < .001). Moderate positive correlation with the MANSA (r = .55, p < .001) and the RAS (r = .60, p < .001) were found. The mean total I.ROC scores increased significantly between time points (F(2,166) = 6.351, p < .005), although differences were small. Confirmatory factor analysis showed that fit indices for the one-, two-, and four-factor model are comparable.

CONCLUSIONS

The I.ROC is a valid and reliable instrument, with sensitivity to change, to map recovery in participants with SSD.

Selection bias in clinical studies of first-episode psychosis: A follow-up study

OBJECTIVES

Selection bias is a concern in studies on psychotic disorders due to high dropout rates and many eligibility criteria for inclusion. We studied how representative the first-episode psychosis study sample in the Turku Early Psychosis Study (TEPS) was.

METHODS

We screened 3772 consecutive admissions to the clinical psychiatric services of Turku Psychiatry, Finland, between October 2011 and June 2016. A total of 193 subjects had first-episode psychosis and were suitable for TEPS. Out of 193 subjects, 101 participated (PA) and 92 did not participate (NPA) in TEPS due to refusal or contact problems. We retrospectively used patient register data to study whether NPA and PA groups differed in terms of clinical outcomes during 1-year follow-up.

RESULTS

In overall sample, the NPA group had a significantly higher rate of discontinuation of clinical treatment than the PA group (48.9 % vs 29.7 %, p = 0.01). In the hospital-treated subsample chi-square tests did not indicate statistically significant differences between the NPA and PA groups in the rate of involuntary care (69.7 % vs 62.7 %, p = 0.34), coercive measures (36.0 % vs 22.7 %, p = 0.06), and readmissions during the follow-up (41.5 % vs 33.8 %, p = 0.31), respectively.

CONCLUSION

The differences in clinical outcomes and treatment characteristics in the non-participating and participating groups were relatively modest. The results do not support a major sample selection bias that would complicate the interpretation of results in this first-episode psychosis study.

Interaction Testing and Polygenic Risk Scoring to Estimate the Association of Common Genetic Variants With Treatment Resistance in Schizophrenia

IMPORTANCE

About 20% to 30% of people with schizophrenia have psychotic symptoms that do not respond adequately to first-line antipsychotic treatment. This clinical presentation, chronic and highly disabling, is known as treatment-resistant schizophrenia (TRS). The causes of treatment resistance and their relationships with causes underlying schizophrenia are largely unknown. Adequately powered genetic studies of TRS are scarce because of the difficulty in collecting data from well-characterized TRS cohorts.

OBJECTIVE

To examine the genetic architecture of TRS through the reassessment of genetic data from schizophrenia studies and its validation in carefully ascertained clinical samples.

DESIGN, SETTING, AND PARTICIPANTS

Two case-control genome-wide association studies (GWASs) of schizophrenia were performed in which the case samples were defined as individuals with TRS (n = 10 501) and individuals with non-TRS (n = 20 325). The differences in effect sizes for allelic associations were then determined between both studies, the reasoning being such differences reflect treatment resistance instead of schizophrenia. Genotype data were retrieved from the CLOZUK and Psychiatric Genomics Consortium (PGC) schizophrenia studies. The output was validated using polygenic risk score (PRS) profiling of 2 independent schizophrenia cohorts with TRS and non-TRS: a prevalence sample with 817 individuals (Cardiff Cognition in Schizophrenia [CardiffCOGS]) and an incidence sample with 563 individuals (Genetics Workstream of the Schizophrenia Treatment Resistance and Therapeutic Advances [STRATA-G]).

MAIN OUTCOMES AND MEASURES

GWAS of treatment resistance in schizophrenia. The results of the GWAS were compared with complex polygenic traits through a genetic correlation approach and were used for PRS analysis on the independent validation cohorts using the same TRS definition.

RESULTS

The study included a total of 85 490 participants (48 635 [56.9%] male) in its GWAS stage and 1380 participants (859 [62.2%] male) in its PRS validation stage. Treatment resistance in schizophrenia emerged as a polygenic trait with detectable heritability (1% to 4%), and several traits related to intelligence and cognition were found to be genetically correlated with it (genetic correlation, 0.41-0.69). PRS analysis in the CardiffCOGS prevalence sample showed a positive association between TRS and a history of taking clozapine (r2 = 2.03%; P = .001), which was replicated in the STRATA-G incidence sample (r2 = 1.09%; P = .04).

CONCLUSIONS AND RELEVANCE

In this GWAS, common genetic variants were differentially associated with TRS, and these associations may have been obscured through the amalgamation of large GWAS samples in previous studies of broadly defined schizophrenia. Findings of this study suggest the validity of meta-analytic approaches for studies on patient outcomes, including treatment resistance.

Attrition in longitudinal studies among patients with schizophrenia and other psychoses; findings from the STRATA collaboration

A major problem with longitudinal studies is the bias generated due to attrition, particularly apparent amongst patients suffering from psychotic disorders. Factors associated with study-participation were investigated as part of a larger research collaboration (STRATA). Out of 479 eligible participants, only 50 (10,4%) were successfully followed up. The present study investigated whether study participation differed depending on baseline characteristics. Results indicated that individuals who did not participate were more likely to report an alcohol use disorder while those who did respond were more likely to have been in full-time education for longer and be of white ethnicity. Participation did not differ depending on diagnosis, symptoms, GAF, age of onset or depression.

Premorbid Social Functioning and Affective Symptoms Predict Subjective Outcome Among Outpatients With Schizophrenia

Improving the subjective outcome of patients is an important target in the treatment of schizophrenia. Accordingly, the aim of the present study was to examine the association of factors deemed relevant in this context, i.e., premorbid functioning, residual symptoms, and side effects of antipsychotic medication, with subjective outcome. To this end, 70 clinically stable outpatients with schizophrenia were included into a cross-sectional study. Premorbid functioning, psychopathology, and side effects were assessed by using the Premorbid Adjustment Scale, the Positive and Negative Syndrome Scale, and the Udvalg for Kliniske Undersogelser Side Effect Rating Scale, respectively. Subjective outcome was measured in terms of life satisfaction (Life Satisfaction Questionnaire), self-esteem (Index of Self-Esteem), and needs for care (Berliner Bedürfnisinventar). Both premorbid social functioning and affective symptoms predicted life satisfaction, self-esteem, and patients' basic needs, whereas positive and negative symptoms predicted needs in the health, social, and functional domains. Concerning side effects, parkinsonism and akathisia showed a significant negative correlation with self-esteem. These findings highlight the complex nature of subjective outcome in patients suffering from schizophrenia. Evidently, premorbid social functioning plays a prominent role in the experienced subjective outcome during the course of the illness. Furthermore, these preliminary findings underscore that constant efforts are essential to treat residual symptoms of the disorder and to avoid extrapyramidal motor side effects of antipsychotic medication. Longitudinal studies are needed to investigate this latter point in more detail.