Polygenic risk for psychiatric disorder and singleness in patients with severe mental illness and controls

Consensus paper of the WFSBP task force on cannabis, cannabinoids and psychosis

OBJECTIVES

The liberalisation of cannabis laws, the increasing availability and potency of cannabis has renewed concern about the risk of psychosis with cannabis.

METHODS

The objective of the WFSBP task force was to review the literature about this relationship.

RESULTS

Converging lines of evidence suggest that exposure to cannabis increases the risk for psychoses ranging from transient psychotic states to chronic recurrent psychosis. The greater the dose, and the earlier the age of exposure, the greater the risk. For some psychosis outcomes, the evidence supports some of the criteria of causality. However, alternate explanations including reverse causality and confounders cannot be conclusively excluded. Furthermore, cannabis is neither necessary nor sufficient to cause psychosis. More likely it is one of the multiple causal components. In those with established psychosis, cannabis has a negative impact on the course and expression of the illness. Emerging evidence also suggests alterations in the endocannabinoid system in psychotic disorders.

CONCLUSIONS

Given that exposure to cannabis and cannabinoids is modifiable, delaying or eliminating exposure to cannabis or cannabinoids, could potentially impact the rates of psychosis related to cannabis, especially in those who are at high risk for developing the disorder.

Magical thinking in individuals with high polygenic risk for schizophrenia but no non-affective psychoses-a general population study

A strong genetic background for psychoses is well-established. Most individuals with a high genetic risk for schizophrenia, however, do not develop the disorder. We investigated whether individuals, who have a high genetic risk for schizophrenia but no non-affective psychotic disorders, are predisposed to develop milder forms of deviant thinking in terms of magical thinking. Participants came from the population-based Young Finns Study (n = 1292). The polygenic risk score for schizophrenia (PRS) was calculated on the basis of the most recent genome-wide association study (GWAS). Psychiatric diagnoses over the lifespan were collected up to 2017 from the registry of hospital care. Magical thinking was evaluated with the Spiritual Acceptance Scale (e.g., beliefs in telepathy, miracles, mystical events, or sixth sense) of the Temperament and Character Inventory in 1997, 2001, and 2012 (participants were 20-50-year-olds). We found that, among those who did not develop non-affective psychotic disorders, high PRS predicted higher magical thinking in adulthood (p = 0.001). Further, PRS predicted different developmental courses: a low PRS predicted a steady decrease in magical thinking from age 20 to 50 years, while in individuals with high PRS the decrease in magical thinking ceased in middle age so that their level of magical thinking remained higher than expected for that age. These findings remained when controlling for sex, childhood family environment, and adulthood socioeconomic factors. In conclusion, if high PRS does not lead to a non-affective psychotic disorder, it predicts milder forms of deviant thinking such as elevated magical thinking in adulthood, especially in middle age. The finding enhances our understanding of different outcomes of high genetic psychosis risk.

The Danish OPUS Early Intervention Services for First-Episode Psychosis: A Phase 4 Prospective Cohort Study With Comparison of Randomized Trial and Real-World Data

OBJECTIVE

The Danish OPUS trial showed significant efficacy of early intervention services for first-episode schizophrenia spectrum disorders compared with standard treatment, leading to implementation of the OPUS intervention in clinical practice. The authors sought to determine whether the effectiveness of OPUS treatment in real-world clinical practice is comparable to the efficacy seen in the trial.

METHODS

The study compared patients who received OPUS treatment as part of the original randomized trial to those who received standard treatment in the trial (the control group) and those who received OPUS treatment after it was implemented in Denmark. The authors investigated whether the three groups differed on register-based outcomes, such as use of secondary health care, functional outcomes, and death. Analyses were adjusted for relevant confounders.

RESULTS

Compared with trial study participants, patients who received OPUS treatment after implementation (N=3,328) had a tendency toward lower mortality (hazard ratio=0.60, 95% CI=0.33, 1.09), fewer and shorter psychiatric admissions, and possibly fewer filled prescriptions of antipsychotics and other psycholeptics after 4 or 5 years. While at first less likely to be working or studying, patients who received postimplementation OPUS treatment eventually had higher odds of working than did those in the OPUS trial (after 5 years, odds ratio=1.49, 95% CI=1.07, 2.09). The odds of being in a couple relationship were also higher among patients in the postimplementation group than those in the trial. Other outcomes showed less clear associations with treatment group. Generally, the control group in the trial fared worse than both of the OPUS treatment groups.

CONCLUSIONS

Not only did OPUS treatment maintain its efficacy after it was implemented as a standard treatment, it paralleled or surpassed many of the effects observed when the OPUS intervention was delivered in a randomized trial. The study results provide further evidence in support of implementation and funding of early intervention services worldwide.

The risk of anxiety disorders in children of parents with severe psychiatric disorders: a systematic review and meta-analysis

BACKGROUND

Several studies have investigated the association between parental severe psychiatric disorders and anxiety disorder risk in offspring, but the findings across these studies have been inconsistent.

METHODS

Using the PRISMA guideline, a rigorous electronic and manual search was conducted in four electronic databases EMBASE, PubMed, PsychINFO, and Scopus to identify relevant studies. All observation studies (cohort and case-control studies) that examined the association between parental severe psychiatric disorders and the risk of offspring anxiety disorders were identified. Summary risk ratios (RRs) and 95% confidence intervals (95%CI) were synthesized using a fixed and random effect meta-analysis.

RESULTS

Twenty-five studies were included in the final analysis (14 cohort and 11 case-control studies). The meta-analysis showed that parental severe psychiatric disorder was associated with a higher risk of social phobia, panic, obsessive-compulsive, post-traumatic stress, separation anxiety, and generalized anxiety disorders in the offspring. When considering specific severe psychiatric disorders in parents as exposure, parental bipolar disorder was associated with an increased risk of obsessive-compulsive and generalized anxiety disorders in the offspring, whereas parental depressive disorder was associated with an increased risk of social phobia, separation anxiety, and generalized anxiety disorders in the offspring. Conversely, parental schizophrenia was not associated with offspring anxiety disorder CONCLUSION: This review suggests that the offspring of parents with severe psychiatric, bipolar, and depressive disorders are at an increased risk of developing a range of anxiety disorders. These findings suggest that targeted early screening and intervention programs are imperative in exposed offspring.

No evidence of associations between genetic liability for schizophrenia and development of cannabis use disorder

BACKGROUND

Cannabis use and cannabis use disorder (CUD) is increased in patients with schizophrenia. It is important to establish if this is explained by non-causal factors, such as shared genetic vulnerability. We aimed to investigate whether the polygenic risk scores (PRS) for schizophrenia and other psychiatric disorders would predict CUD in controls, patients with schizophrenia, and patients with other psychiatric disorders.

METHODS

We linked nationwide Danish registers and genetic information obtained from dried neonatal bloodspots in an observational analysis. We included people with schizophrenia, other psychiatric disorders, and controls. The exposures of interest were the PRS for schizophrenia, attention-deficit hyperactivity disorder (ADHD) autism spectrum disorder, and anorexia nervosa. The main outcome of interest was the diagnosis of CUD.

RESULTS

The study included 88 637 individuals. PRS for schizophrenia did not predict CUD in controls [hazard ratio (HR) = 1.16, 95% CI 0.95-1.43 per standard-deviation increase in PRS, or HR = 1.47, 95% CI 0.72-3.00 comparing highest v. remaining decile], but PRS for ADHD did (HR = 1.27, 95% CI 1.08-1.50 per standard-deviation increase, or HR = 2.02, 95% CI 1.27-3.22 for the highest decile of PRS). Among cases with schizophrenia, the PRS for schizophrenia was associated with CUD. While CUD was a strong predictor of schizophrenia (HR = 4.91, 95% CI 4.36-5.53), the inclusion of various PRS did not appreciably alter this association.

CONCLUSION

The PRS for schizophrenia was not associated with CUD in controls or patients with other psychiatric disorders than schizophrenia. This speaks against the hypothesis that shared genetic vulnerability would explain the association between cannabis and schizophrenia.