Cannabis is the most commonly used illicit substance in Ireland and globally. It is most likely to be used in adolescence, a period of biopsychosocial vulnerability to maladaptive behaviours. This study aims to investigate the risk and protective factors for cannabis use among adolescents.

This study is a secondary analysis of the cross-sectional Planet Youth survey (2021). The sample comprised 4,404 adolescents aged 15–16 from one urban and two rural areas in Ireland. The outcome of interest was current cannabis use, defined as cannabis use within the last 30 days. Independent variables i.e., risk and protective factors, were selected a priori following a literature review. Associations between cannabis use and the independent variables were explored using mixed-effects logistic regressions.

The prevalence of current cannabis use was 7.3% and did not differ significantly between males and females. In fully-adjusted models, significant risk factors for cannabis use were: Having peers that used cannabis (Adjusted Odds Ration (aOR) 10.17, 95% CI: 5.96–17.35); Parental ambivalence towards cannabis use (aOR 3.69, 95% CI: 2.41–5.66); Perception of cannabis as non-harmful (aOR 2.32,95% CI 1.56–£.45): Other substance use (aORs ranging from 2-67–3.15); Peer pressure to use cannabis (aOR 1.85,95% CI 1.05–3.26), and Low parental supervision (aOR 1.11, 95% CI: 1.01–1.22).

This study identified key individual, peer-to-peer and parental risk factors associated with adolescent cannabis use, several of which have the potential to be modified through drug prevention strategies.

Markers of inflammation and cannabis exposure are associated with an increased risk of mental disorders. In the current study, we investigated associations between cannabis use and biomarkers of inflammation.

Utilizing a sample of 914 participants from the Avon Longitudinal Study of Parents and Children, we investigated whether interleukin-6 (IL-6), tumor necrosis factor α (TNFα), C-reactive protein (CRP), and soluble urokinase plasminogen activator receptor (suPAR) measured at age 24 were associated with past year daily cannabis use, less frequent cannabis use, and no past year cannabis use. We adjusted for a number of covariates including sociodemographic measures, body mass index, childhood trauma, and tobacco smoking. We found evidence of a strong association between daily or near daily cannabis use and suPAR.

We did not find any associations between less frequent cannabis use and suPAR. We did not find evidence of an association between IL-6, TNFα or CRP, and cannabis use.

Our finding that frequent cannabis use is strongly associated with suPAR, a biomarker of systemic chronic inflammation implicated in neurodevelopmental and neurodegenerative processes is novel. These findings may provide valuable insights into biological mechanisms by which cannabis affects the brain and impacts the risk of serious mental disorders.

This study provides data on the prevalence of mental health problems among adolescents in Ireland in 2021, toward the end of the COVID-19 pandemic. The importance of having recent, large-scale, mental health data for adolescents has been heightened by COVID-19, the increased demand for child and adolescent mental health services, and the rapidly changing adolescent environment.

As part of the Planet Youth study, a cross-sectional survey of adolescents (N = 4,404), mostly aged 15–16, was conducted between September and December 2021. Participants were recruited from 40 schools and non-traditional educational centres across 3 regions in Ireland, one predominantly urban (North Dublin) and two predominantly rural (Cavan, Monaghan). A range of mental health outcomes were self-reported: a single-item question on mental health; the Strengths & Difficulties Questionnaire (SDQ); depressive and anxiety symptoms from the Symptom Check List 90; the Adolescent Psychotic-like Symptom Screener; and lifetime self-harm, suicidal ideation, and attempt.

Over a quarter of adolescents described their mental health as ‘bad’ or ‘very bad’ (29%), and had SDQ total problem scores over 20 (26%). Over a third (39%) reported self-harming, 42% reported suicidal ideation, and 11% reported attempting suicide, in their lifetime. Gender-diverse youth (non-binary, trans, and undisclosed) had higher rates of poor mental health outcomes compared to cis-gendered youth (male/female), and females had higher rates of most mental health outcomes compared to males.

Many of these estimates suggest a deterioration from previous epidemiological studies. While our findings do not definitively prove youth mental health has worsened over time, these findings are highly concerning. We propose a close monitoring of mental health in future surveys of this population and encourage initiatives to improve the capacity and quality of youth mental health services.

Developmental trauma increases psychosis risk and is associated with poor prognosis. It has been proposed that psychosis in survivors of developmental trauma gives rise to a distinct ‘traumatogenic’ phenotype.

Given the implications for personalised treatment, we sought to explore the traumatogenic psychosis phenotype hypothesis in a systematic review and meta-analysis of studies comparing psychotic presentations between adults with and without developmental trauma histories.

We registered the systematic review on PROSPERO (CRD42019131245) and systematically searched EMBASE, Medline and PsycINFO. The outcomes of interests were quantitative and qualitative comparisons in psychotic symptom expression (positive, negative, cognitive) and other domains of psychopathology, including affect regulation, sleep, depression and anxiety, between adults with and without experience of developmental trauma.

Of 34 studies included (N = 13 150), 11 were meta-analysed (n = 2842). A significant relationship was found between developmental trauma and increased symptom severity for positive (Hedge's g = 0.27; 95% CI 0.10–0.44; P = 0.002), but not negative symptoms (Hedge's g = 0.13; 95% CI −0.04 to 0.30; P = 0.14). Developmental trauma was associated with greater neurocognitive, specifically executive, deficits, as well as poorer affect, dissociation and social cognition. Furthermore, psychotic symptom content thematically related to traumatic memories in survivors of developmental trauma.

Our findings that developmental trauma is associated with more severe positive and affective symptoms, and qualitative differences in symptom expression, support the notion that there may be a traumatogenic psychosis phenotype. However, underdiagnosis of post-traumatic stress disorder may also explain some of these findings. More research is needed to explore this further.

Previous population-based studies have identified suicidal ideation (SI) as a potential risk marker for psychosis. We aimed to investigate the prevalence of previous SI in a large sample of patients with first episode of psychosis accepted to early intervention services (EIS) in South London and Maudsley (SLaM) NHS Foundation Trust using clinical records. We further aimed to investigate differences in patients with and without recorded SI according to age at diagnosis, gender, ethnicity and neighbourhood deprivation.

We designed a retrospective cohort using the Clinical Record Interactive System. Included were patients who were accepted by SLaM EIS from 2015–2018 and received a psychotic disorder diagnosis (n = 1658). We used a natural language processing algorithm that searches deidentified textual clinical records, returning a binary variable indicating presence or absence of SI recorded at any time prior to acceptance to EIS. The algorithm has high precision (97%) and inter-rater reliability (Cohen's k 92%). The t-test was used to compare mean age at first diagnosis in patients with and without recorded SI, while chi-squared tests evaluated differences according to gender, ethnicity and tertiles of index of multiple deprivation (based on 2015 postcode). The significance threshold was p = 0.05.

The cohort included 1658 patients, of whom 656 (39.6%) were female. The natural language processing algorithm identified 600 patients (36.2%) who had SI recorded in their clinical records at any time prior to acceptance by EIS. On average, patients with recorded SI were younger at first diagnosis of psychotic disorder (mean 27.7 years, standard deviation 10.5) compared with patients without recorded SI (mean 30.1 years, standard deviation 11.2; p < 0.001). There was little evidence for differences on gender (p = 0.950), ethnicity (p = 0.059) or deprivation index (p = 0.597).

Approximately 1 in 3 patients attending SLaM EIS had evidence of SI recorded prior to acceptance by EIS. Consistent with previous studies, the current findings emphasise the high prevalence of SI in this clinical population. Compared with those without SI, patients with recorded SI were on average 2–3 years younger at diagnosis. This may reflect general population age differences in prevalence of suicidal ideation; increased severity of illness with earlier age of onset; or patterns of contact with services which facilitated earlier diagnosis. There was little evidence that patients with and without recorded SI differed significantly on gender, ethnicity or neighbourhood deprivation. Prospective studies would be helpful to assess whether SI is a risk marker for first episode of psychosis.

The thalamus, a dual grey matter formation within the diencephalon is thought to be involved in psychosis. It consists of distinct nuclei with specific functions. To date no study has investigated the volumes of the thalamic nuclei in young adolescents with Psychotic Experiences (PEs).

This study used T1 imaging with Freesurfer analysis to investigate the differences in thalamic nuclei in 98 young people (53 with PEs) over three time points, from ages 11 to 18. A linear mixed effects (LME) model was used to examine the longitudinal nature of the data.

The findings were entirely left sided – specifically a smaller left whole thalamus (p = 0.04), significant reduction in the size of the left pulvinar (p = 0.008) and a slight increase in the size of left ventral nucleus (p = 0.005).

This study found significant volumetric differences in thalamic functional composite nuclei between adolescents with a history of PE compared with healthy controls. Two such nuclear groups survived post-hoc DTR testing, the left ventral and left pulvinar nuclei. The pulvinar nucleus demonstrated a reduced volume over time in PE groups compared with healthy controls whilst the left ventral nucleus demonstrated an increased volume over time in PE groups compared with controls. The thalamus has been shown to be actively involved in the modulation of cortico-cortical communication via cortico-thalamo-cortical pathways, thus synchronizing the activity of the cortex during tasks that require attention. One of the core deficits believed to be a part of psychotic illnesses is the inappropriate modulation of attention through various cortical networks. This disrupted modulation results in a lack of control of goal-directed behaviour and can be attributed to the changes seen in pulvinar in psychotic illnesses, thus resulting in impairment in the integrity of sensory information and context processing. The affiliation of the ventral thalamic nucleus to the dopaminergic system, particularly the substantia nigra, may aid in explaining why this nucleus demonstrates larger volumes in adolescents with PEs compared with healthy controls over time.

More research needs to be done on following this cohort up, specifically investigating changes in thalamic nuclei in those who develop a diagnosable psychotic disorder.

Prenatal and perinatal complications are established risk factors for psychotic disorder, but far less is known about these measures and psychotic experiences (PEs). We investigated the longitudinal effect of prenatal risk factors (maternal behavior, medication complications) and perinatal risk factors (birth weight, medical complications) on frequency of PEs. We also examined the cumulative risk of prenatal/perinatal risk factors, and differences between transient PE, persistent PE, and controls.

The Adolescent Brain Cognitive Development study is a large child cohort (age 9–10 at baseline; n = 11 872 with PE data). PEs were measured longitudinally using the Prodromal Questionnaire-Brief, Child version, and included only if reported as distressing. Mixed-effects models were used for analysis, controlling for random effects, and a substantial number of fixed-effects covariates.

Urinary tract infection (β = 0.11, 95% confidence interval [CI] 0.03–0.19) and severe anemia (β = 0.18, 95% CI 0.07–0.29) increased frequency of distressing PEs in childhood. Number of prenatal complications increased frequency of PEs (β = 0.03, 95% CI 0.01–0.06) and risk of persistent PEs (odds ratio [OR] = 1.08, 95% CI 1.01–1.15). Maternal smoking was associated with an increased frequency of PEs (β = 0.11, 95% CI 0.04–0.18) and persistent PEs (OR = 1.31, 95% CI 1.04–1.66). Maternal substance use was a risk factor for a 48% increased risk of persistent PEs (OR = 1.48, 95% CI 1.08–2.01). Perinatal complications showed no effect on PEs.

This study provides evidence that certain prenatal medical complications (severe nausea, severe anemia), cumulative number of prenatal medical complications, and maternal behaviors (smoking during pregnancy), increased frequency of distressing PEs in childhood. Maternal smoking and substance use, as well as cumulative number of prenatal complications increased risk of persistent PEs.

Psychotic disorders exhibit a complex aetiology that combines genetic and environmental factors. Among the latter, obstetric complications (OCs) have been widely studied as risk factors, but it is not yet well understood how OCs relate to the heterogeneous presentations of psychotic disorders. We assessed the clinical phenotypes of individuals with a first episode of psychosis (FEP) in relation to the presence of OCs.

Two-hundred seventy-seven patients with an FEP were assessed for OCs using the Lewis–Murray scale, with data stratified into three subscales depending on the timing and the characteristics of the obstetric event, namely: complications of pregnancy, abnormal foetal growth and development and difficulties in delivery. We also considered other two groups: any complications during the pregnancy period and all OCs taken altogether. Patients were clinically evaluated with the Positive and Negative Syndrome Scale for schizophrenia.

Total OCs and difficulties in delivery were related to more severe psychopathology, and this remained significant after co-varying for age, sex, traumatic experiences, antipsychotic dosage and cannabis use.

Our results highlight the relevance of OCs for the clinical presentation of psychosis. Describing the timing of the OCs is essential in understanding the heterogeneity of the clinical presentation.

To reduce both inappropriate testing for and diagnosis of healthcare-onset (HO) Clostridioides difficile infections (CDIs).

We performed a retrospective analysis of C. difficile testing from hospitalized children before (October 2017–October 2018) and after (November 2018–October 2020) implementing restrictive computerized provider order entry (CPOE).

Study sites included hospital A (a ∼250-bed freestanding children’s hospital) and hospital B (a ∼100-bed children’s hospital within a larger hospital) that are part of the same multicampus institution.

In October 2018, we implemented CPOE. No testing was allowed for infants aged ≤12 months, approval of the infectious disease team was required to test children aged 13–23 months, and pathology residents’ approval was required to test all patients aged ≥24 months with recent laxative, stool softener, or enema use. Interrupted time series analysis and Mann-Whitney U test were used for analysis.

An interrupted time series analysis revealed that from October 2017 to October 2020, the numbers of tests ordered and samples sent significantly decreased in all age groups (P < .05). The monthly median number of HO-CDI cases significantly decreased after implementation of the restrictive CPOE in children aged 13–23 months (P < .001) and all ages combined (P = .003).

Restrictive CPOE for CDI in pediatrics was successfully implemented and sustained. Diagnostic stewardship for CDI is likely cost-saving and could decrease misdiagnosis, unnecessary antibiotic therapy, and overestimation of HO-CDI rates.

Research has shown a strong relationship between hallucinations and suicidal behaviour in general population samples. Whether hallucinations also index suicidal behaviour risk in groups at elevated risk of suicidal behaviour, namely in individuals with a sexual assault history, remains to be seen.

We assessed whether hallucinations were markers of risk for suicidal behaviour among individuals with a sexual assault history.

Using the cross-sectional 2007 (N = 7403) and 2014 (N = 7546) Adult Psychiatric Morbidity Surveys, we assessed for an interaction between sexual assault and hallucinations in terms of the odds of suicide attempt, as well as directly comparing the prevalence of suicide attempt in individuals with a sexual assault history with v. without hallucinations.

Individuals with a sexual assault history had increased odds of hallucinations and suicide attempt compared to individuals without a sexual assault history in both samples. There was a significant interaction between sexual assault and hallucinations in terms of the odds of suicide attempt. In total, 14–19% of individuals with a sexual assault history who did not report hallucinations had one or more suicide attempt. This increased to 33–52% of individuals with a sexual assault history who did report hallucinations (2007, aOR = 2.85, 1.71–4.75; 2014, aOR = 4.52, 2.78–7.35).

Hallucinations are a risk marker for suicide attempt even among individuals with an elevated risk of suicidal behaviour, specifically individuals with a sexual assault history. This finding highlights the clinical significance of hallucinations with regard to suicidal behaviour risk, even among high-risk populations.

To examine the impact of the first full year of the COVID-19 pandemic and its associated restrictions on the volume and nature of psychiatric presentations to an emergency department (ED) in a large academic hospital.

Anonymised clinical data on psychiatric presentations to the ED were collected for the 52-week period from the start of the COVID-19 pandemic and compared with corresponding 1 year periods in 2019 and 2018.

There was a significant increase in psychiatric presentations overall to the ED during the first year of the COVID-19 pandemic compared to previous years, in contrast to a reduction in total presentations for all other specialties. There was a marked increase in psychiatric presentations of those below 18 years, and in the 30–39 years and 40–49 years age groups, but a decrease in the 18–29 years group. There was a significant increase in anxiety disorder presentations but a decrease in alcohol related presentations. There was no significant change observed in the rates of presentations for self-harm or suicidal ideation.

Psychiatric presentations to the ED have increased during the first year of the COVID-19 pandemic in contrast to a decrease in presentations for other medical specialties, with this increase being driven by out-of-hours presentations. The fourfold increase in presentations of young people below the age of 18 years to the ED with mental health difficulties is an important finding and suggests a disproportionate burden of psychological strain placed on this group during the pandemic.

Psychotic experiences are reported by 5–10% of young people, although only a minority persist and develop into psychotic disorders. It is unclear what characteristics differentiate those with transient psychotic experiences from those with persistent psychotic experiences that are more likely to be of clinical relevance.

To investigate how longitudinal profiles of psychotic experiences, created from assessments at three different time points, are influenced by early life and co-occurring factors.

Using data from 8045 individuals from a birth cohort study, longitudinal profiles of psychotic experiences based on semi-structured interviews conducted at 12, 18 and 24 years were defined. Environmental, cognitive, psychopathological and genetic determinants of these profiles were investigated, along with concurrent changes in psychopathology and cognition.

Following multiple imputations, the distribution of longitudinal profiles of psychotic experiences was none (65.7%), transient (24.1%), low-frequency persistent (8.4%) and high-frequency persistent (1.7%). Individuals with high-frequency persistent psychotic experiences were more likely to report traumatic experiences, other psychopathology, a more externalised locus of control, reduced emotional stability and conscientious personality traits in childhood, compared with those with transient psychotic experiences. These characteristics also differed between those who had any psychotic experiences and those who did not.

These findings indicate that the same risk factors are associated with incidence as with persistence of psychotic experiences. Thus, it might be that the severity of exposure, rather than the presence of specific disease-modifying factors, is most likely to determine whether psychotic experiences are transient or persist, and potentially develop into a clinical disorder over time.

Cognitive and motor dysfunction are hallmark features of the psychosis continuum, and have been detected during late childhood and adolescence in youth who report psychotic experiences (PE). However, previous investigations have not explored infancy and early childhood development. It remains unclear whether such deficits emerge much earlier in life, and whether they are associated with psychotic, specifically hallucinatory, experiences (HE).

This study included data from Gen2 participants of The Raine Study (n = 1101), a population-based longitudinal cohort study in Western Australia. Five areas of childhood development comprising: communication; fine motor; gross motor; adaptive (problem-solving); and personal-social skills, were assessed serially at ages 1, 2 and 3 years. Information on HE, depression and anxiety at ages 10, 14 and 17 years was obtained. HE were further subdivided into those with transient or recurrent experiences. Mixed effects logistic regression models and cumulative risk analyses based on multiple domain delays were performed.

Early poorer development in multiple areas was noted from ages 1, 2 and 3 years among youth who reported HE. Early developmental delays significantly increased the risk for later HE. This association was particularly marked in the recurrent HE group, with over 40% having early developmental delays in multiple domains. There was no significant association between early childhood development and later anxiety/depression apart from lower gross motor scores at age 3.

The findings suggest that early pan-developmental deficits are associated with later HE, with the effect strongest for young people who report recurrent HE throughout childhood and adolescence.