Genome-wide analyses reveal shared genetic architecture and novel risk loci between opioid use disorder and general cognitive ability

BACKGROUND

Opioid use disorder (OUD), a serious health burden worldwide, is associated with lower cognitive function. Recent studies have demonstrated a negative genetic correlation between OUD and general cognitive ability (COG), indicating a shared genetic basis. However, the specific genetic variants involved, and the underlying molecular mechanisms remain poorly understood. Here, we aimed to quantify and identify the genetic basis underlying OUD and COG.

METHODS

We quantified the extent of genetic overlap between OUD and COG using a bivariate causal mixture model (MiXeR) and identified specific genetic loci applying conditional/conjunctional FDR. Finally, we investigated biological function and expression of implicated genes using available resources.

RESULTS

We estimated that ~94% of OUD variants (4.8k out of 5.1k variants) also influence COG. We identified three novel OUD risk loci and one locus shared between OUD and COG. Loci identified implicated biological substrates in the basal ganglia.

CONCLUSION

We provide new insights into the complex genetic risk architecture of OUD and its genetic relationship with COG.

Genome-wide analyses reveal novel opioid use disorder loci and genetic overlap with schizophrenia, bipolar disorder, and major depression

Opioid use disorder (OUD) and mental disorders are often comorbid, with increased morbidity and mortality. The causes underlying this relationship are poorly understood. Although these conditions are highly heritable, their shared genetic vulnerabilities remain unaccounted for. We applied the conditional/conjunctional false discovery rate (cond/conjFDR) approach to analyse summary statistics from independent genome wide association studies of OUD, schizophrenia (SCZ), bipolar disorder (BD) and major depression (MD) of European ancestry. Next, we characterized the identified shared loci using biological annotation resources. OUD data were obtained from the Million Veteran Program, Yale-Penn and Study of Addiction: Genetics and Environment (SAGE) (15 756 cases, 99 039 controls). SCZ (53 386 cases, 77 258 controls), BD (41 917 cases, 371 549 controls) and MD (170 756 cases, 329 443 controls) data were provided by the Psychiatric Genomics Consortium. We discovered genetic enrichment for OUD conditional on associations with SCZ, BD, MD and vice versa, indicating polygenic overlap with identification of 14 novel OUD loci at condFDR < 0.05 and 7 unique loci shared between OUD and SCZ (n = 2), BD (n = 2) and MD (n = 7) at conjFDR < 0.05 with concordant effect directions, in line with estimated positive genetic correlations. Two loci were novel for OUD, one for BD and one for MD. Three OUD risk loci were shared with more than one psychiatric disorder, at DRD2 on chromosome 11 (BD and MD), at FURIN on chromosome 15 (SCZ, BD and MD) and at the major histocompatibility complex region (SCZ and MD). Our findings provide new insights into the shared genetic architecture between OUD and SCZ, BD and MD, indicating a complex genetic relationship, suggesting overlapping neurobiological pathways.

The evaluation of the impact of anti-stigma training led by "experts by experience" on participants' attitudes towards persons with mental illness

OBJECTIVES

The purpose of this study was to evaluate the impact of anti-stigma training led by people who had previously experienced mental health crises (i.e., "experts by experience") on various aspects of participants' attitudes towards the people with mental illness.

METHODS

The three-hour workshops were attended by 185 people; the training was held in 17 groups, with 3-19 people in each (11 on average). Almost half of the participants (45.4%) were employees of the mental health care system. The participants were asked to fill out a set of questionnaires immediately before and after the training, which evaluated the following aspects of their attitudes: social distance, stigmatizing attributions, beliefs about self-determination/ ability to attain important life goals by people with mental illness, and also beliefs about the social value of people with mental illness. The respondents were asked to complete the same set of questionnaires again online a month and six months after the training. The data were analyzed based on a piecewise latent trajectory model.

RESULTS

Out of the 185 people who participated in the workshops, 115 (62.2%) filled out the questionnaires a month after, and 87 (47.0%) six months after the training. The analyses showed an improvement in all four measures of attitudes expressed directly after the training. In three out of the four examined aspects of attitudes (intensity of social distance, stigmatizing attributions and beliefs about self-determination of people with mental illness) the positive impact of the training continued after six months.

CONCLUSIONS

The results provide preliminary empirical evidence that the structured antistigma intervention under evaluation, using the elements of education and interpersonal contact can be an effective tool for improving social attitudes towards people with mental illness.

Clozapine-induced myocarditis during co-administration of valproate: A case report

Clozapine, atypical antipsychotic drug, is widely used in patients with schizophrenia, for whom previous therapy was inadequate or not tolerated. Clozapine-induced myocarditis (CIM) is a relatively rare but potentially life-threatening complication of clozapine therapy; however, the underlying mechanism has not been so far well elucidated. Factors predisposing to CIM include a rapid dose titration, advanced age and co-administration of sodium valproate. In this paper, we present a case of a 22-year-old male patient with refractory schizophrenia who developed CIMduring low-dose clozapine treatment with co-administration of valproate and risperidone. On the basis of our case and literature review, we point out that during the first weeks of clozapine treatment patients should be actively, daily monitored for the presence of symptoms suggesting CIM. The low dose of clozapine and concurrent use of valproate are unique aspects of the report, adding new information to the discussion on safety of concomitant use of clozapine and valproate. Further investigation is required to better understand the role of co-administration of valproate and risperidone in the pathogenesis of CIM.