David Castle

• MB ChB MSc MD DLSHTM GCUT FRCPsych FRANZCP
• Professor at University of Tasmania

Aim: This paper provides a detailed account of the process and outcomes involved in adapting a psychosocial intervention – the Optimal Health Program (OHP) – for young individuals who are at clinical high risk (CHR) for psychosis. This adaptation process included the active participation of youth with lived experience of psychosis spectrum disorder...

Background Many people who contract the SAR-CoV-2 virus present with multiple persistent and debilitating physical, cognitive and mental health symptoms that endure beyond the acute infection period. This new syndrome – generally referred to as long COVID – negatively affects patients’ emotional wellbeing and quality of life, and presents a major c...

Background Individuals with serious mental illness (SMI) have higher rates of comorbid physical health conditions, poorer associated health outcomes, and die on average 10–20 years earlier than the general population. This qualitative study aimed to explore the perspectives and experiences of adults living with SMI and family members with accessing...

Background Individuals experiencing serious mental illness (SMI) have higher rates of comorbid physical health conditions, poorer associated health outcomes, and die on average 10–20 years earlier than the general population. They encounter multiple barriers to accessing appropriate physical health care in many countries, including Canada, where po...

Background Drug development in Alzheimer’s disease (AD) over the past two decades has had high rates of failure. Novel trial designs, such as adaptive designs, have the potential to improve the efficiency of drug development in AD. Objective To evaluate the design characteristics, temporal trends, and differences in design between sponsor types in...

Background Mental health service users are more likely to smoke tobacco and are as likely to make quit attempts as people not experiencing SMI, but they are less likely to succeed. Quitting tobacco can be harder for people experiencing SMI due to higher levels of nicotine dependence, more severe withdrawal, and many other complex factors. The Quitl...

Objective The aim of this umbrella review is to summarise existing international evidence on means restriction activities for the prevention of suicide, and provide evidence of their success or lack thereof. The consolidated and integrated information can help inform potential public health interventions. Methods An overview of published systemati...

Background The prenatal and early-life periods pose a crucial neurodevelopmental window whereby disruptions to the intestinal microbiota and the developing brain may have adverse impacts. As antibiotics affect the human intestinal microbiome, it follows that early-life antibiotic exposure may be associated with later-life psychiatric or neurocognit...

This chapter describes the diagnostic and clinical features of body dysmorphic disorder (BDD). The chapter synthesizes clinical and research findings with relevant case material to illustrate important clinical features. The overall aim of the chapter is to provide a practical guide for clinicians.

This chapter focuses on the assessment of body dysmorphic disorder (BDD). We begin with a focus on assessment at the initiation of treatment in psychological/psychiatric settings. People with BDD are often reticent to talk about their issues or see their problem as being ameliorable only by a cosmetic "fix". Thus, the mental health professional nee...

Basket trials can efficiently evaluate a single treatment across multiple diseases with a common shared target. Prior methods for randomized basket trials required baskets to have the same sample and effect sizes. To that end, we developed a general randomized basket trial with an interim analysis (RaBIt) that allows for unequal sample sizes and ef...

Background Decreasing suicide mortality has become an overarching goal for societies worldwide. Suicide registers and other monitoring systems are a valuable source of information that can be used for addressing the suicide phenomenon and evaluating preventative interventions. Aims This scoping review provides an overview of literature published i...

Aims This systematic review aims to identify and synthesise the publicly available research testing treatments for mental health, cognition and psychological well-being in long COVID. Methods The following databases and repositories were searched in October–November 2023: Medline, Embase, APA PsycINFO, Cumulative Index to Nursing and Allied Health...

Objectives Identifying demographic risk and protective factors for continued substance use in late life may identify groups in need of health care resources. Here, we assess demographic risk factors of past-year cannabis, stimulants, opioid, and tranquilizer use in young and older adults from a United States sample as well as lifetime use in older...

Basket trial designs with interim analysis have gained significant attention due to their adaptability, flexibility, and scalability. In response to the need for user-friendly tools that enhance the real-world applicability of these designs, we developed a web-based interface aimed at facilitating two-stage basket trial designs. Built using R Shiny...

Objective We present an evaluation of antipsychotic prescribing in an inpatient psychiatry ward in Hobart, Tasmania, to establish pattern of use, alignment with other psychiatric wards or centres and the recommendations in the Royal Australian and New Zealand College of Psychiatry Clinical Practice Guidelines, and to determine predictors of polypha...

Background and Hypothesis. Cognitive impairment is a core feature of schizophrenia spectrum disorders (SSD). While the relationship between cognition and symptoms in SSD has been extensively studied, there is a lack of research focusing on individual item-level analysis rather than relying on summary score methodology. Our previous study on a firs...

Objective Since the federal Canadian government legalized cannabis in 2018, cannabis use in the general population has slightly increased. However, little is known about the impact of cannabis legalization on pattens of cannabis use in psychiatric populations. Method We studied changes in daily/almost daily and average 30-day cannabis use amongst...

Individuals with clinical high risk (CHR) for psychosis experience significant distress, impaired general functioning and a high lifetime risk of self-harm and attempted suicide. The CHR period is an important phase in an individual’s mental health where appropriate interventions may reduce the risk of progression to several negative outcomes, incl...

Background Peer support involves people (mentors) using their own experiences to assist others (mentees). The impetus to include peer support in eating disorder recovery is high, however research on implementation of peer roles in eating disorder management is limited. A previous pilot study found positive but preliminary results for a Peer Mentor...

Background and Hypothesis Substance use is highly prevalent among people with schizophrenia (SCZ) and related disorders, however, there is no broad-spectrum pharmacotherapy that concurrently addresses both addiction and psychotic symptoms. Psychosocial (PS) interventions, which have yielded promising results in treating psychosis and substance depe...

Background: Neurocognitive impairment is a core feature of schizophrenia spectrum disorders (SSDs), and the relationship between cognition and symptoms in SSDs has been widely researched. Negative symptoms are related to a wide range of cognitive impairments; however, the aspects of negative symptoms that underpin this relationship have yet to be s...

Objective: People with mental health conditions have high rates of chronic physical diseases, partially attributable to lifestyle risks factors. This study examined risk prevalence among community mental health service clients, their readiness and confidence to change, and associations with participant characteristics. Methods: Cross-sectional s...

This study assessed the rate of a.) the total and b.) specific psychiatric comorbidities among the three severity ratings for Anorexia Nervosa (AN): DSM-5, ICD-11 and overvaluation of weight and shape (OWS). The sample comprised 312 treatment-seeking patients with AN (mean age = 26.9). Weight and height were taken at intake to calculate BMI, the fo...

"Revolving door" patients refer to those who are frequently rehospitalized for relapse. This phenomenon can be explained by a multitude of factors, including a lack of medical and/or social support. Through a review of various modalities of psychiatric treatment—such as long-acting injectables, assisted outpatient treatment, and telehealth—it is cl...

Objective: Abnormal visual processing has been proposed as a mechanism underlying excessive focus on minor appearance flaws in body dysmorphic disorder (BDD). Existing BDD research has not differentiated the various stages of face processing (featural, first-order configural, holistic and second-order configural) that are required for higher-order...

Medical assistance in dying for mental illness as a sole underlying medical condition (MAiD MI-SUMC) is a controversial and complex policy in terms of psychosocial and ethical medical practice implications. We discuss the status of MAiD MI-SUMC in Canada and argue for the use of the UK Medical Research Council's framework on complex interventions i...

Background Persons with mental illness as their sole underlying medical condition are eligible to access medical assistance in dying (MAiD) in a small number of countries, including Belgium, the Netherlands, Luxemburg and Switzerland. In Canada, it is anticipated that people experiencing mental illness as their sole underlying medical condition (MI...

Objective Monoamine neurotransmitters play a role in aggression, especially when altered by illicit substances. However, some literature suggests that not all illicit substances may lead to aggression, notably psychedelics. This narrative review investigates the associations between serotonergic psychedelics and MDMA on aggressive behaviour. Metho...

Introduction: Obsessive compulsive disorder (OCD) represents a complex and often difficult to treat disorder. Pharmacological and psychotherapeutic interventions are often associated with sub-optimal outcomes, and 40-60% of patients are resistant to first line therapies and thus left with few treatment options. OCD is underpinned by aberrant neuro...

Disorders of gambling are more common among the mentally ill, including in people with psychotic disorders. The aim of this study was to conduct a systematic review of the literature regarding the prevalence and correlates of gambling disorders in people with psychotic disorders. We systematically reviewed English-language literature through search...

The advent of dopamine (D2) receptor-blocking medications over 70 years ago, ushered in a new era of biological treatment for schizophrenia. However, we argue that little subsequent progress has been made in translating this into fulfilled and fulfilling lives for people with schizophrenia. This Viewpoint asks why this is the case, and suggests way...

Schizophrenia is a severe psychiatric disorder associated with significant comorbidities and early mortality. People with schizophrenia have a greater predisposition to the top 6 modifiable global mortality (cardiometabolic) risk factors as defined by the World Health Organization (compared with the general population). These are driven by genetic,...

Objectives Cognitive flexibility and psychological distress, such as depression and anxiety, have been implicated in the aetiology of Anorexia Nervosa (AN). Despite the known associations between eating disorder (ED) symptoms, depression, anxiety, and cognitive flexibility, the specific pathways that connect these constructs are unclear. We therefo...

Objective To review the literature on the impact of gonadal hormones on features of borderline personality disorder. Background Oestrogen flux and absolute sex hormone levels are known to be associated with various mood states in women. We investigated whether this was particularly relevant for borderline symptoms in women with or without borderli...

Background: Deep brain stimulation (DBS) is a promising treatment option for treatment- refractory obsessive-compulsive disorder (OCD). Several stimulation targets have been used, mostly in and around the anterior limb of the internal capsule and ventral striatum (VC/VS). However, the precise target within this region remains a matter of debate. Me...

Aim Deep brain stimulation (DBS) is a safe and effective treatment option for people with refractory obsessive‐compulsive disorder (OCD). Yet our understanding of predictors of response and prognostic factors remains rudimentary, and long‐term comprehensive follow‐ups are lacking. We aim to investigate the efficacy of DBS therapy for OCD patients,...

Background and Aims Δ9‐tetrahydrocannabinol (THC), the principal psychoactive component of cannabis, has been implicated in affecting fetal neurodevelopment by readily crossing the placenta. However, little is known regarding the long‐term effects of intrauterine cannabis exposure. This systematic review and meta‐analysis synthesized prospective an...

Medical assistance in dying (MAiD) was introduced into Canadian federal legislation in 2016. Mental illness as the sole underlying medical condition (MI-SUMC) is currently excluded from eligibility; such exclusion is scheduled to expire on March 17, 2024. Irremediability, capacity, quality of life, autonomy, family involvement, and healthcare syste...

Background Long COVID (LC) symptoms persist 12 weeks or more beyond the acute infection. To date, no standardised diagnostic/treatment pathways exist. However, a holistic approach has been recommended. This study explores participants’ experiences of a Long COVID Optimal Health Programme (LC-OHP); a psychoeducational self-efficacy programme. Aim T...

Background A large proportion of Australians are affected by mental illness each year, and treatment gaps are well known. To meet current and future demands and enable access to treatment that is safe, effective, and acceptable, a robust and sustainable mental health workforce is required. Factors reported to attract people to work within the menta...

Objective This lived experience-engaged study aims to understand patient and family perspectives on the relationship between suicidality and medical assistance in dying when the sole underlying medical condition is mental illness (MAiD MI-SUMC). Method Thirty individuals with mental illness (age M = 41.8 years, SD = 14.2) and 25 family members (ag...

The majority of people who contract COVID-19 experience a short period of symptomatic infection. However, symptoms persist for months or years following initial exposure to the virus in some cases. This has been described as long COVID. Little is known about the lived experience of this condition, as it has only recently emerged. This study aimed t...

Background A constellation of often disabling long-term physical symptoms enduring after an acute SARS-COV-2 infection is commonly referred to as Long COVID. Since Long COVID is a new clinical entity, research is required to clarify treatment needs and experiences of individuals affected. This qualitative descriptive study aimed to provide insight...

The current scientific enquiry of deep brain stimulation (DBS) does not capture the breadth of DBS-induced changes to an individual’s life. Considering that DBS is applied in severe and complex cases, it is ethically and clinically necessary to consider the patient perspective and personally relevant outcomes. This lived experience investigation of...

High staff turnover is common within the Australian public mental health workforce, contributing to workforce shortages and ultimately impacting the ability to provide stable efficient, effective, and ongoing optimal care to the community. In this study, we aimed to (a) establish the most pertinent factors associated with increased turnover intenti...

Body Dysmorphic Disorder (BDD) is characterized by an intense preoccupation with one or more perceived “defects” in physical appearance. Despite the distress and impairment associated with BDD, the disorder remains understudied and poorly understood. In particular, there are limited studies available which give voice to those with firsthand experie...

Introduction Long COVID (LC) is a multisystem illness, with fluctuating symptoms that affect the daily activities of patients. There are still no standardised diagnostic criteria or treatment approaches for managing LC. The LC‐Optimal Health Programme (LC‐OHP) was designed to support the mental wellbeing and physical health of people with LC. Gaini...

Background Stepped-wedge cluster randomized trials (SWCRTs) are a type of cluster-randomized trial in which clusters are randomized to cross-over to the active intervention sequentially at regular intervals during the study period. For SWCRTs, sequential imbalances of cluster-level characteristics across the random sequence of clusters may lead to...

In 2019, we developed a large-scale study to comprehensively investigate the biopsychosocial factors and mechanisms involved in AN titled ‘Investigating the Cause and maintenance of Anorexia Nervosa’ or the ‘I-CAN study’. The overarching aim was to conduct a detailed investigation of the underlying factors involved in AN, which would enable us to c...

Objective To systematically assess credibility and certainty of associations between cannabis, cannabinoids, and cannabis based medicines and human health, from observational studies and randomised controlled trials (RCTs). Design Umbrella review. Data sources PubMed, PsychInfo, Embase, up to 9 February 2022. Eligibility criteria for selecting s...

Background and Hypothesis. Neurocognitive impairment is a core feature of schizophrenia spectrum disorders (SSDs), and the relationship between cognition and symptoms in SSDs is widely researched. The most well-replicated finding is an association between episodic memory and negative symptoms; however, the aspects of negative symptoms that underpin...

Background: Randomised controlled trials (RCTs) of psilocybin have reported large antidepressant effects in adults with major depressive disorder and treatment-resistant depression (TRD). Given psilocybin's psychedelic effects, all published studies have included psychological support. These effects depend on serotonin 2A (5-HT2A) receptor activat...

Medical assistance in dying (MAiD) was introduced into Canadian legislation in 2016. Mental illness as the sole underlying medical condition (MI-SUMC) is excluded from eligibility; this is expected to change in 2024. Incurability, intolerable suffering, capacity to make healthcare decisions, and suicidality have been publicly debated in connection...

Objective: The aim of this study was to test the effectiveness of a tailored quitline tobacco treatment ('Quitlink') among people receiving support for mental health conditions. Methods: We employed a prospective, cluster-randomised, open, blinded endpoint design to compare a control condition to our 'Quitlink' intervention. Both conditions rece...

Introduction Long COVID (LC) is a multisystem disease with symptoms lasting weeks or months beyond the acute COVID-19 infection. Several manifestations are reported by people with LC, including effects on mental health, with varying degrees of psychological distress and disturbances to daily activities. Research conducted to identify effective inte...

An updated third edition of this award-winning book provides a comprehensive overview of the complex associations between cannabis and mental illness. Organised into easy to navigate sections, the book has been fully revised to feature eight entirely new chapters covering important novel aspects. Marijuana and Madness incorporates new research find...

Background: For individuals living with diabetes and its psychosocial comorbidities (eg, depression, anxiety, and distress), there remains limited access to interprofessional, integrated care that includes mental health support, education, and follow-up. Health technology, broadly defined as the application of organized knowledge or skill as softw...

BACKGROUND A large proportion of Australians are affected by mental illness each year, and treatment gaps are well known. To meet current and future demands and enable access to treatment which is safe, effective, and acceptable, a robust and sustainable mental health workforce is required. Factors reported to attract people to work within the ment...

Aims: To determine whether the risk of psychotic symptoms during weeks of methamphetamine use was dependent on, increased by, or independent of having a family history of psychosis. Design: Secondary analysis of 13 contiguous 1-week periods of data (1370 weeks). A risk modification framework was used to test each scenario. Setting: Geelong, Wo...

Background: People with substance use disorder have a high risk of SARS-CoV-2 infection and subsequent poor outcomes. Few studies have evaluated COVID-19 vaccine effectiveness among people with substance use disorder. We aimed to estimate the vaccine effectiveness of BNT162b2 (Fosun-BioNTech) and CoronaVac (Sinovac) against SARS-CoV-2 omicron (B.1...

Severe and refractory psychiatric patients can experience complex and profound changes in symptomology, functioning and well-being from deep brain stimulation (DBS) therapy. Currently, the efficacy of DBS is assessed by clinician rated scales of primary symptoms, yet this does not capture the multitude of DBS mediated changes or represent the patie...

Study objectives: To investigate the trends in the consumption of benzodiazepines (BZDs) and Z-drugs at global, regional, and national levels from 2008 to 2018, across 67 countries and regions. Methods: This cross-sectional descriptive study investigated the consumption of BZDs and Z-drugs analysed by global pharmaceutical sales data from the IQ...

Purpose of Review Substance-induced psychosis (SIP) is a term used to refer to a psychotic disorder triggered by recent substance use. The purpose of this review article is to discuss how to diagnose/assess individuals with SIP versus schizophrenia; how to differentiate between these conditions; morbidity and mortality; etiology; risk factors for S...

Objective: In the general population, repeated cognitive testing produces learning effects with potential for improved test performance. It is currently unclear whether the same effect of repeated cognitive testing on cognition pertains to people living with schizophrenia, a condition often associated with significant cognitive impairments. This s...

Background Eating disorders (EDs) are complex psychological disorders, with low rates of detection and early intervention. They can lead to significant mental and physical health complications, especially if intervention is delayed. Given high rates of morbidity and mortality, low treatment uptake, and significant rates of relapse, it is important...

There is substantial contemporary interest in psychedelic agents as medicines for maladies of the mind. This follows research in the 1950s and 1960s exploring the use of LSD and other psychedelics to treat a range of psychiatric illnesses as well as addictions. This research was shut down after prohibition of these drugs; however, the last decade h...

There is substantial contemporary interest in psychedelic agents as medicines for maladies of the mind. This follows research in the 1950s and 1960s exploring the use of LSD and other psychedelics to treat a range of psychiatric illnesses as well as addictions. This research was shut down after prohibition of these drugs; however, the last decade h...

Chronic kidney disease (CKD) negatively impacts psychological well-being and quality of life (QoL). Underpinned by the Common Sense Model (CSM), this study evaluated the potential mediating role of self-efficacy, coping styles and psychological distress on the relationship between illness perceptions and QoL in patients living with CKD. Participant...

Introduction Current treatment options for major depressive disorder (MDD) have limited efficacy and are associated with adverse effects. Recent studies investigating the antidepressant effect of serotonergic psychedelics—also known as classic psychedelics—have promising preliminary results with large effect sizes. In this context, we conducted a r...

Purpose The COVID-19 pandemic has highlighted the difficulties healthcare systems face to care for patients with chronic diseases. In the state of Victoria, Australia, the government implemented a state-wide lockdown and restricted the delivery of healthcare to limit the spread of the virus. This study investigated the impact of the pandemic on hea...

Plain English summary Our understanding of the prevalence and impact of eating disorders has improved significantly over the past 20-years. Research highlights that rates of eating disorders are increasing. To inform the development of the Eating Disorder Research and Translation Strategy 2021–2031 this review aimed to better understand the global...

Objective Currently available treatments for eating disorders lack efficacy resulting in poor outcomes for patients. In this paper, we describe a number of issues that we have identified in our clinical service, which are not unique to our treatment program. Conclusions The issues described are common among eating disorder services worldwide and n...

Background: Risk factors represent a range of complex variables associated with the onset, development, and course of eating disorders. Understanding these risk factors is vital for the refinement of aetiological models, which may inform the development of targeted, evidence-based prevention, early intervention, and treatment programs. This Rapid...

Objectives Perturbations of the intestinal microbiota have been associated with mental health disorders, including major depressive disorder (MDD). Therefore, faecal microbiota transplantation (FMT) holds promise as a microbiota-modulating treatment for MDD. Yet, to date, there are no published controlled studies evaluating the use of FMT for MDD....

Background Mental disorders, including major depressive disorder (MDD), are a leading cause of non-fatal burden of disease globally. Current conventional treatments for depression have significant limitations, and there have been few new treatments in decades. The microbiota-gut-brain-axis is now recognised as playing a role in mental and brain hea...

Perinatal depression is the onset of depressive symptoms during pregnancy and up to one year after childbirth. Migrant women are at higher risk of experiencing perinatal depression due to numerous psychosocial stressors related to their experiences. This qualitative review aims to aggregate the experiences and barriers to care faced by immigrant an...

Background Clinical use of psychedelics has gained considerable attention, with promising benefits across a range of mental disorders. Current pharmacological and psychotherapeutic treatments for body dysmorphic disorder (BDD) and eating disorders (EDs) have limited efficacy. As such, other treatment options such as psychedelic-assisted therapies a...

The COVID‐19 pandemic led to significant adaptations to healthcare. Provision of mental healthcare in a changing environment presented healthcare workers with unique challenges and demands, including changes in workload and expectations. To inform current and future healthcare service responses, and adaptations, the current review aimed to collate...

BACKGROUND For individuals living with diabetes and its psychosocial comorbidities (eg, depression, anxiety, and distress), there remains limited access to interprofessional, integrated care that includes mental health support, education, and follow-up. Health technology, broadly defined as the application of organized knowledge or skill as softwar...

Background Delayed diagnosis, gaps in services and subsequent delays in specialist care and treatment lead to poorer health outcomes for individuals with eating disorders (EDs) and drive significant government healthcare expenditure. Given the significant disease burden associated with EDs, it is imperative that current implementation research is s...

Background Despite significant advances in the understanding and treatment of obsessive compulsive disorder (OCD), current treatment options are limited in terms of efficacy for symptom remission. Thus, assessing the potential role of iterative or alternate psychotherapies is important. Also, the potential role of digital technologies to enhance th...

Repetitive transcranial magnetic stimulation (rTMS) is a promising treatment for cannabis use disorder in schizophrenia; however, gaps in the literature remain as to the potential role of neurocognitive functioning in treatment response. We evaluated the moderating role of select cognitive functions including baseline executive functioning, verbal...