The effect of drug use on the age at onset of psychotic disorders in an Australian cohort

Stress, Environment and Early Psychosis

Existing literature provides extended evidence of the close relationship between stress dysregulation, environmental insults, and psychosis onset. Early stress can sensitize genetically vulnerable individuals to future stress, modifying their risk for developing psychotic phenomena. Neurobiological substrate of the aberrant stress response to hypothalamic-pituitary-adrenal axis dysregulation, disrupted inflammation processes, oxidative stress increase, gut dysbiosis, and altered brain signaling, provides mechanistic links between environmental risk factors and the development of psychotic symptoms. Early-life and later-life exposures may act directly, accumulatively, and repeatedly during critical neurodevelopmental time windows. Environmental hazards, such as pre- and perinatal complications, traumatic experiences, psychosocial stressors, and cannabis use might negatively intervene with brain developmental trajectories and disturb the balance of important stress systems, which act together with recent life events to push the individual over the threshold for the manifestation of psychosis. The current review presents the dynamic and complex relationship between stress, environment, and psychosis onset, attempting to provide an insight into potentially modifiable factors, enhancing resilience and possibly influencing individual psychosis liability.

Age of onset by sex in schizophrenia: Proximal and distal characteristics

BACKGROUND

Earlier schizophrenia onset in men relative to women has been a consistent finding in the literature, but a nuanced understanding of underlying reasons remains elusive. Further consideration should be given to factors associated with sex differences in age of onset.

METHOD

Participants with schizophrenia were derived from the 2010 Australian Survey of High Impact Psychosis (n = 857). The SHIP survey constituted a representative, population-based study of almost 1.5 million Australian adults seen at various mental health services, and assessed personal health information, psychiatric comorbidities as well as psychosis illness and treatment. Hierarchical clustering was employed to identify age of onset by sex. Within-sex comparisons on distal and proximal factors affecting age of onset were conducted.

RESULTS

Using modal age, two and three clusters were respectively found in men (early versus late onset) and women (early versus mid versus late onset). Early onset groups in both sexes had an increased family history of psychosis compared to older onset, but other risk factors were not consistent across the sexes. Less premorbid impairment was noted in females with middle to later onset schizophrenia.

CONCLUSION

These findings further inform our understanding of the pathogenesis of schizophrenia. Added explorations of trends in older onset schizophrenia cohorts is especially important.

Schizophrenia and substance use disorder: Characteristics of coexisting issues in a forensic setting

BACKGROUND AND AIMS

Recent research has identified higher prevalence of offending behavior in patients with comorbid schizophrenia spectrum disorder (SSD) and substance use disorder (SUD) compared to patients with SSD only and to the general population. However, findings on the subgroup of patients with SUD, SSD and offending behavior in forensic psychiatric care are scarce and inconsistent. The present study used machine learning to uncover more detailed characteristics of offender patients in forensic psychiatric care with comorbid SSD and SUD.

METHODS

Using machine learning algorithms, 370 offender patients (91.6 % male, mean age of M = 34.1, SD = 10.2) and 558 variables were explored in order to build three models to differentiate between no substance use disorder, cannabis use disorder and any other substance use disorder. To counteract the risk of overfitting, the dataset was split, employing variable filtering, machine learning model building and selection embedded in a nested resampling approach on one subset. The best model was then selected and validated on the second data subset.

RESULTS

Distinguishing between SUD vs. no drug use disorder yielded models with an AUC of 70 and 78. Variables assignable to demographics, social disintegration, antisocial behavior and illness were identified as most influential for the distinction. The model comparing cannabis use disorder with other substance use disorders provided no significant differences.

CONCLUSIONS

From a clinical perspective, offender patients suffering from schizophrenia spectrum and comorbid substance use disorder seem particularly challenging to treat, but initial differences in psychopathology will dissipate over inpatient treatment. Our data suggest that offender patients may benefit from appropriate treatment that focuses on illicit drug abuse to reduce criminal behavior and improve social integration.

Legalized Cannabis in Colorado Emergency Departments: A Cautionary Review of Negative Health and Safety Effects

Cannabis legalization has led to significant health consequences, particularly to patients in emergency departments and hospitals in Colorado. The most concerning include psychosis, suicide, and other substance abuse. Deleterious effects on the brain include decrements in complex decision-making, which may not be reversible with abstinence. Increases in fatal motor vehicle collisions, adverse effects on cardiovascular and pulmonary systems, inadvertent pediatric exposures, cannabis contaminants exposing users to infectious agents, heavy metals, and pesticides, and hash-oil burn injuries in preparation of drug concentrates have been documented. Cannabis dispensary workers (“budtenders”) without medical training are giving medical advice that may be harmful to patients. Cannabis research may offer novel treatment of seizures, spasticity from multiple sclerosis, nausea and vomiting from chemotherapy, chronic pain, improvements in cardiovascular outcomes, and sleep disorders. Progress has been slow due to absent standards for chemical composition of cannabis products and limitations on research imposed by federal classification of cannabis as illegal. Given these factors and the Colorado experience, other states should carefully evaluate whether and how to decriminalize or legalize non-medical cannabis use.

Clinical characteristics of primary psychotic disorders with concurrent substance abuse and substance-induced psychotic disorders: A systematic review

BACKGROUND

Distinguishing between a primary psychotic disorder with concurrent substance abuse (PPD+SA) and a substance-induced psychotic disorder (SIPD) can be diagnostically challenging. We aimed to determine if these two diagnoses are clinically distinct, particularly in relation to psychopathology. In addition, we aimed to examine the specific clinical features of cannabis-induced psychotic disorder (CIPD) as compared to primary psychotic disorder with concurrent cannabis abuse (PPD+CA) and also to SIPD associated with any substance.

METHODS

A systematic review of SIPD literature using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Using strict inclusion criteria, a total of six studies examining SIPD were included in the review (two of which only considered psychosis induced by cannabis alone). The findings did not reveal many consistent differences in psychopathology. However, we did find that that compared to PPD+SA, individuals with SIPD have a weaker family history of psychotic disorder; a greater degree of insight; fewer positive symptoms and fewer negative symptoms; more depression (only in CIPD) and more anxiety.

CONCLUSION

There remains a striking paucity of information on the psychopathology, clinical characteristics and outcome of SIPD. Our review highlights the need for further research in this area.

Demographic and clinical correlates of substance use disorders in first episode psychosis

BACKGROUND

We assessed the prevalence and correlates of lifetime substance use disorders in people with first episode psychosis using the baseline data from the Recovery After an Initial Schizophrenia Episode (RAISE) Early Treatment Program study.

METHODS

Research staff assessed 404 first episode patients at 34 community mental health centers across the United States with the Structured Clinical Interview for DSM-IV for diagnoses of psychotic and substance use disorders. Logistic regression was used to evaluate the relationships between participant characteristics and lifetime substance use disorders, followed with generalized linear mixed-effects regression models to identify unique predictors of lifetime substance use disorders.

RESULTS

Approximately one-third of participants reported recent alcohol use (36.6%) and cannabis use (30.7%), and one half (51.7%) met criteria for any lifetime alcohol or drug use disorder. Lifetime substance use disorders were associated with male gender, White race, higher excited (hyperactivity, mood lability, impulsivity, hostility, and uncooperativeness), psychotic and depressive symptoms, less impaired cognition, and greater perceived stigma. Gender, race, and excited symptoms were the most consistent unique predictors of lifetime substance use disorders found in multivariate analyses.

CONCLUSIONS

Half of first episode psychosis patients have co-occurring substance use disorders, which are associated with both more severe symptoms and greater perceptions of stigma. Programs aiming to serve these patients must have the skills and clinical strategies to help people with these unique characteristics.

Men and women with psychosis and the impact of illness-duration on sex-differences: The second Australian national survey of psychosis

We aimed to examine and compare sex-differences in people receiving treatment for psychotic illnesses in community settings, based on long or short duration of illness; expecting association between longer illness-duration and worse outcomes in women and men. Clinical, demographic and service-use data from the Survey of High Impact Psychosis were analysed by sex and duration of illness (≤5 years; ≥6 years), using independent t-tests, chi-square tests, one-way ANOVA, and Cramer's V. Of the 1825 participants, 47% had schizophrenia, 17.5% bipolar and 16.1% schizo-affective disorders. More women than men had undertaken post-school education, maintained relationships, and been living in their own homes. Women with a shorter-illness-duration showed social functioning equivalent to non-ill women in the general population. Men tended to have an early illness onset, show premorbid dysfunction, be single, show severe disability, and to use illicit substances. Men with a longer-illness-duration were very socially disadvantaged and isolated, often experiencing homelessness and substance use. Men with a short-illness-duration were most likely to be in paid employment, but two-thirds earned less than $AUD500 per fortnight. Men with longer-illness-duration showed most disability, socially and globally. Interventions should be guided by diagnosis, but also by a person's sex and duration of illness.

The effects of tobacco smoking on age of onset of psychosis and psychotic symptoms in a first-episode psychosis population

BACKGROUND AND AIMS

Research suggests that tobacco smokers may develop psychosis at an earlier age than non-smokers, with effects on psychotic symptoms. We aimed to test the difference in age of onset of psychosis between smokers and non-smokers.

DESIGN

Self-report data were collected from smokers and non-smokers in a population of first-episode psychosis patients.

SETTING

Out-patient first-episode psychosis programme in Santander (Cantabria), Spain.

PARTICIPANTS

Three hundred and ninety-seven patients (226 male, 171 female) who agreed to take part between 2001 and 2011.

MEASUREMENTS

Age of onset of psychosis, age of smoking initiation, demographics, family history of psychosis and cannabis use were collected by self-report.

FINDINGS

Kaplan-Meier analysis showed that smokers had a significantly lower mean age of psychosis onset [smokers = 27.4 (± 8.1) years, non-smokers = 30.5 (± 9.9) years] than non-smokers (χ²₍₁₎  = 11.72, P = 0.001). The Cox proportional hazard model showed no significant difference in the age of psychosis onset between smokers and non-smokers adjusted for covariates [hazard ratio (HR) = 1.034, 95% confidence interval (CI) = 0.828-1.291]. Age of psychosis onset was predicted significantly by cannabis use (HR = 2.073, 95% CI = 1.633-2.633) and gender (HR = 1.706, 95% CI = 1.363-2.135).

CONCLUSIONS

Smokers do not appear to have a significantly earlier age of psychosis onset than non-smokers after taking into account cannabis use and gender.

Responding to challenges for people with psychotic illness: Updated evidence from the Survey of High Impact Psychosis

OBJECTIVE

The objective is to summarise recent findings from the 2010 Australian Survey of High Impact Psychosis (SHIP) and examine their implications for future policy and planning to improve mental health, physical health and other circumstances of people with a psychotic disorder.

METHODS

Survey of High Impact Psychosis collected nationally representative data on 1825 people with psychotic illness. Over 60 papers have been published covering key challenges reported by participants: financial problems, loneliness and social isolation, unemployment, poor physical health, uncontrolled symptoms of mental illness, and lack of stable, suitable housing. Findings are summarised under the rubric of participant-ranked top challenges.

RESULTS

The main income source for the majority (85%) of participants was a government benefit. Only one-third was employed, and the most appropriate employment services for this group were under-utilised. High rates of loneliness and social isolation impacted mental and physical health. The rate of cardiometabolic disease was well above the general population rate, and associated risk factors were present from a very young age. Childhood abuse (30.6%), adult violent victimisation (16.4%) and alcohol and substance abuse/dependence (lifetime rates of 50.5% and 54.5%, respectively) complicated the clinical profile. Treatment with medication was suboptimal, with physical health conditions undertreated, a high rate of psychotropic polypharmacy and underutilisation of clozapine in chronic persistent psychotic illness. Only 38.6% received evidence-based psychosocial therapies. In the previous year, 27.4% had changed housing and 12.8% had been homeless, on average for 155 days.

CONCLUSION

Money, social engagement and employment are the most important challenges for people with psychotic illness, as well as good physical and mental health. An integrated approach to recovery is needed to optimise service delivery and augment evidence-based clinical practice with measures to improve physical health and social circumstances. Meeting these challenges has the potential to reduce costs to government and society, as well as promote recovery.

Premorbid cannabis use is associated with more symptoms and poorer functioning in schizophrenia spectrum disorder

BACKGROUND

Cannabis use disorder is associated with an earlier age at onset and a more severe outcome of schizophrenia spectrum disorders. The role of cannabis use before the onset of illness (premorbid cannabis use) has not been fully investigated. We here examined how amount and type of premorbid cannabis use was associated with the later course of illness including current substance use, symptoms and level of functioning in schizophrenia spectrum disorder.

METHOD

We used a naturalistic sample of patients with DSM-IV schizophrenia spectrum disorders with a comprehensive history of illness and substance use. Data on premorbid substance use was obtained from comprehensive self-report. The relationship to outcome was investigated using regression models that included current substance use and premorbid functioning.

RESULTS

Pre-schizophrenia cannabis use was significantly associated with more severe psychotic symptoms and impaired functioning. Higher levels of premorbid cannabis use were associated with higher levels of current psychotic symptoms. These associations were independent of current substance use and premorbid functioning. Early use of cannabis (age <17 years) was associated with earlier age at onset of psychosis, independently of potential confounders.

CONCLUSIONS

Pre-psychosis cannabis use affects illness outcome in schizophrenia spectrum disorders, and is associated with lower age at onset of psychosis. These findings of independent negative effects of premorbid cannabis use in schizophrenia suggest that a limitation of the general use of cannabis may have beneficial health effects.

Sociodemographic and psychiatric diagnostic predictors of 3-year incidence of DSM-IV substance use disorders among men and women in the National Epidemiologic Survey on Alcohol and Related Conditions

Incidence rates of alcohol and drug use disorders (AUDs and DUDs) are consistently higher in men than women, but information on whether sociodemographic and psychiatric diagnostic predictors of AUD and DUD incidence differ by sex is limited. Using data from Waves 1 and 2 of the National Epidemiologic Survey on Alcohol and Related Conditions, sex-specific 3-year incidence rates of AUDs and DUDs among United States adults were compared by sociodemographic variables and baseline psychiatric disorders. Sex-specific logistic regression models estimated odds ratios for prediction of incident AUDs and DUDs, adjusting for potentially confounding baseline sociodemographic and diagnostic variables. Few statistically significant sex differences in predictive relationships were identified and those observed were generally modest. Prospective research is needed to identify predictors of incident DSM-5 AUDs and DUDs and their underlying mechanisms, including whether there is sex specificity by developmental phase, in the role of additional comorbidity in etiology and course, and in outcomes of prevention and treatment.

Psychosis induced by amphetamines

PURPOSE OF REVIEW

The study reviews publications on the use of methamphetamine and amphetamine in relation to psychotic symptoms, substance-induced psychosis, and primary psychosis published between July 2014 and December 2015. The databases MEDLINE, Embase, and PsycINFO were searched using the terms 'amphetamine psychosis' and 'methamphetamine psychosis' for the time period 1 July 2014 to 31 December 2015.

RECENT FINDINGS

There were 37 studies published on the subject during this time period. Risk factors for psychotic symptoms, substance-induced psychosis, and primary psychosis included patterns of drug use, but results also pointed to the importance of nondrug-related vulnerability. Cognitive impairment is associated with both amphetamine use and psychosis, and the impairment among those with amphetamine-induced psychosis resembles that of schizophrenia. At the neuronal level, GABAergic mechanisms may offer some understanding about the association between stimulant use and psychosis. Several different types of antipsychotic medication are effective for treating agitation and psychosis, but drugs with high DRD2 blockade should be used with caution. Some novel treatments are described, but are not sufficiently repeated to be recommended.

SUMMARY

During the past 18 months, studies have been published that cover risk factors, neuronal mechanisms, and treatment. These recent results do not differ from previous understandings, but the role of cognition and GABAergic dysfunction should be further investigated, and knowledge about resilience factors is still scarce. Also, a clearer evidence base for medical treatment of psychosis with concurrent amphetamine use is warranted. VIDEO ABSTRACT.

Royal Australian and New Zealand College of Psychiatrists clinical practice guidelines for the management of schizophrenia and related disorders

OBJECTIVES

This guideline provides recommendations for the clinical management of schizophrenia and related disorders for health professionals working in Australia and New Zealand. It aims to encourage all clinicians to adopt best practice principles. The recommendations represent the consensus of a group of Australian and New Zealand experts in the management of schizophrenia and related disorders. This guideline includes the management of ultra-high risk syndromes, first-episode psychoses and prolonged psychoses, including psychoses associated with substance use. It takes a holistic approach, addressing all aspects of the care of people with schizophrenia and related disorders, not only correct diagnosis and symptom relief but also optimal recovery of social function.

METHODS

The writing group planned the scope and individual members drafted sections according to their area of interest and expertise, with reference to existing systematic reviews and informal literature reviews undertaken for this guideline. In addition, experts in specific areas contributed to the relevant sections. All members of the writing group reviewed the entire document. The writing group also considered relevant international clinical practice guidelines. Evidence-based recommendations were formulated when the writing group judged that there was sufficient evidence on a topic. Where evidence was weak or lacking, consensus-based recommendations were formulated. Consensus-based recommendations are based on the consensus of a group of experts in the field and are informed by their agreement as a group, according to their collective clinical and research knowledge and experience. Key considerations were selected and reviewed by the writing group. To encourage wide community participation, the Royal Australian and New Zealand College of Psychiatrists invited review by its committees and members, an expert advisory committee and key stakeholders including professional bodies and special interest groups.

RESULTS

The clinical practice guideline for the management of schizophrenia and related disorders reflects an increasing emphasis on early intervention, physical health, psychosocial treatments, cultural considerations and improving vocational outcomes. The guideline uses a clinical staging model as a framework for recommendations regarding assessment, treatment and ongoing care. This guideline also refers its readers to selected published guidelines or statements directly relevant to Australian and New Zealand practice.

CONCLUSIONS

This clinical practice guideline for the management of schizophrenia and related disorders aims to improve care for people with these disorders living in Australia and New Zealand. It advocates a respectful, collaborative approach; optimal evidence-based treatment; and consideration of the specific needs of those in adverse circumstances or facing additional challenges.

Cannabis and Psychosis: a Critical Overview of the Relationship

Interest in the relationship between cannabis use and psychosis has increased dramatically in recent years, in part because of concerns related to the growing availability of cannabis and potential risks to health and human functioning. There now exists a plethora of scientific articles addressing this issue, but few provide a clear verdict about the causal nature of the cannabis-psychosis association. Here, we review recent research reports on cannabis and psychosis, giving particular attention to how each report provides evidence relating to two hypotheses: (1) cannabis as a contributing cause and (2) shared vulnerability. Two primary kinds of data are brought to bear on this issue: studies done with schizophrenic patients and studies of first-episode psychosis. Evidence reviewed here suggests that cannabis does not in itself cause a psychosis disorder. Rather, the evidence leads us to conclude that both early use and heavy use of cannabis are more likely in individuals with a vulnerability to psychosis. The role of early and heavy cannabis use as a prodromal sign merits further examination, along with a variety of other problem behaviors (e.g., early or heavy use of cigarettes or alcohol and poor school performance). Future research studies that focus exclusively on the cannabis-psychosis association will therefore be of little value in our quest to better understand psychosis and how and why it occurs.

Does Cannabis Cause, Exacerbate or Ameliorate Psychiatric Disorders? An Oversimplified Debate Discussed

There have been extensive policy shifts in the legality of recreational and therapeutic use of cannabis in the United States, as well as a steady increase in the number of people using the drug on a regular basis. Given these rapid societal changes, defining what is known scientifically about the consequences of cannabis use on mental health takes on added public health significance. The purpose of this circumspectives piece is to discuss evidence of cannabis' effects on two psychiatric conditions: post-traumatic stress disorder and psychotic disorders. Dr Haney and Dr Evins will discuss two viewpoints regarding the benefit and harm of cannabis use for these conditions, while outlining what remains unproven and requires further testing to move the field forward.

Utility of Washington Early Recognition Center Self-Report Screening Questionnaires in the Assessment of Patients with Schizophrenia and Bipolar Disorder

Early identification and treatment are associated with improved outcomes in bipolar disorder (BPD) and schizophrenia (SCZ). Screening for the presence of these disorders usually involves time-intensive interviews that may not be practical in settings where mental health providers are limited. Thus, individuals at earlier stages of illness are often not identified. The Washington Early Recognition Center Affectivity and Psychosis (WERCAP) screen is a self-report questionnaire originally developed to identify clinical risk for developing bipolar or psychotic disorders. The goal of the current study was to investigate the utility of the WERCAP Screen and two complementary questionnaires, the WERC Stress Screen and the WERC Substance Screen, in identifying individuals with established SCZ or BPD. Participants consisted of 35 BPD and 34 SCZ patients, as well as 32 controls (CON), aged 18-30 years. Univariate analyses were used to test for score differences between groups. Logistic regression and receiver operating characteristic (ROC) curves were used to identify diagnostic predictors. Significant group differences were found for the psychosis section of the WERCAP (pWERCAP; p < 0.001), affective section of the WERCAP (aWERCAP; p = 0.001), and stress severity (p = 0.027). No significant group differences were found in the rates of substance use as measured by the WERC Substance Screen (p = 0.267). Only the aWERCAP and pWERCAP scores were useful predictors of diagnostic category. ROC curve analysis showed the optimal cut point on the aWERCAP to identify BPD among our participant groups was a score of >20 [area under the curve (AUC): 0.87; sensitivity: 0.91; specificity: 0.71], while that for the pWERCAP to identify SCZ was a score of >13 (AUC: 0.89; sensitivity: 0.88; specificity: 0.82). These results indicate that the WERCAP Screen may be useful in screening individuals for BPD and SCZ and that identifying stress and substance-use severity can be rapidly done using self-report questionnaires. Larger studies in undiagnosed individuals will be needed to test the WERCAP Screen's ability to identify mania or psychosis in the community.

Improving the efficiency of drug use disorder screening in psychiatric settings: validation of a single-item screen

BACKGROUND

Co-occurring drug use disorders are under-detected in psychiatrically ill populations highlighting the need for more efficient screening tools.

OBJECTIVES

This study compares a single-item screening tool, previously validated in a primary care setting, to the 10-item Drug Abuse Screening Test (DAST-10) for identifying co-occurring drug use disorders among patients with severe psychiatric illness.

METHODS

A total of 395 patients attending a psychiatric partial hospital program completed both the single-item screen and DAST-10. A subsample of consecutive patients (n = 67) was also administered the Structure Clinical Interview for DSM-IV (SCID-IV) as a diagnostic reference standard.

RESULTS

Concordance between screening measures was moderate (κ = 0.4, p < 0.01). Sensitivity and specificity of the single-item screen and DAST-10 as compared to the SCID-IV were comparable, while area under the receiver operating curve showed better discriminatory power for the identification of drug use disorders with the single-item screen.

CONCLUSIONS

In comparison to the DAST-10, the single-item screen appears to be a more efficient tool to identify co-occurring drug use disorders in a psychiatric treatment setting among patients with a range of psychiatric diagnoses.

Environmental factors and the age at onset in first episode psychosis

OBJECTIVE

Factors that influence the age at onset in psychotic disorders could provide valuable insights into precipitating or causative factors of the disorder. Despite being established risk factors, it is not yet known whether migration status, place of birth, social class at birth and season of birth influence the age at onset of psychotic disorders. This study aimed to determine whether these environmental factors, in addition to cannabis abuse and obstetric complications, influence the age at onset. Additionally, we investigated whether environmental factors could have a cumulative effect on the age at onset.

METHOD

Data was obtained from two first episode of psychosis (FEP) cohort studies. Diagnosis was established using the Structured Clinical Interview for DSM IV diagnoses.

RESULTS

The age at onset was determined for 555 individuals with a FEP and the median age at onset was 27.3years. Individuals with a history of cannabis abuse had an earlier age at onset by nearly six years. There was a trend for a history of obstetric complications to be associated with a younger age at onset by 2.7years and this was significant in the subgroup with a family history of psychosis. Social class at birth, migration status, place of birth and season of birth were not associated with the age at onset. Exposure to a higher number of environmental factors was associated with an earlier age at onset.

CONCLUSIONS

Cannabis and obstetric complications are associated with an earlier age at onset and there appears to be a cumulative effect of exposure to multiple environmental factors.

No additive effect of cannabis on cognition in schizophrenia

BACKGROUND

We aimed to examine the association between lifetime cannabis use and estimates of both premorbid and current cognitive function in psychotic disorders in an Australian cohort.

METHODS

In an Australian multicenter cohort, 1237 participants with an established ICD-10 diagnosis of psychotic disorder were categorised according to history of lifetime cannabis use (non-users, n=354; cannabis users, n=221; cannabis dependency, n=662). Groups were analyzed according to available indices of cognitive ability: the National Adult Reading Test - Revised (NART-R) for ability prior to illness onset; and the Digit Symbol Coding Test (DSCT) for current ability. Two-way analysis of variance was conducted without any covariate, followed by a two-way analysis of covariance (using age, age at onset of psychiatric illness, premorbid IQ and the Socio-Economic Index for Areas (SEIFA) rankings).

RESULTS

Whilst there appeared to be a significant association between cannabis use and mean DSCT (higher DSCT scores in cannabis using groups) F(2,1080)=9.478, p<0.001, η2=0.017), once covariates were used in the analysis there were no significant differences between groups in mean DSCT scores (F(2,1011)=0.929, p=0.395, η2=0.002). Similarly there were no differences between groups in mean NART scores once, age, age at illness onset and SEIFA rankings were used as covariates (F(2,1032)=1.617, p=0.199, η2=0.003).

CONCLUSIONS

Confounding variables underpin the association between cannabis use and cognitive function in psychotic disorders. Taken together, it would appear that cannabis use or dependence has no additive effect on cognitive dysfunction in these disorders.

Birth weight and obstetric complications determine age at onset in first episode of psychosis

BACKGROUND

Earlier age at onset of psychosis (AOP) has been associated with poor social adjustment and clinical outcome. Genetic and environmental factors such as obstetric complications, parental history of psychosis, advanced paternal age at time of birth, low birth weight and gestational age, and use of drugs have been described as bringing AOP forward. This study aims to evaluate the relationship between AOP and these factors in a sample of first episode of psychosis (FEP) patients.

METHODS

Clinical and sociodemographic data, age at FEP, age of parents at birth, parental history of psychosis, drug-use habits of the mother during pregnancy and of the patient before psychotic onset, and Lewis and Murray obstetric complication scale were obtained from 90 patients with FEP. Statistical analysis was performed by means of Pearson correlations, Chi-square tests, Student T-test analyses and a linear regression model using SPSS version 22.

RESULTS

Pre-eclampsia, need for incubator at birth, use of forceps, parental history of psychosis, and low birth weight were associated with an earlier AOP. Use of forceps and birth weight are the variables which best predict AOP in FEP. Stimulant drugs, which were mostly used together with cannabis and cocaine, were the only substances associated with an earlier AOP.

CONCLUSIONS

Our findings are consistent with previous study results and underline the role of the prenatal period in the development of psychosis and the importance of careful monitoring of pregnancy and delivery, especially in cases with familial history.