Obsessive-Compulsive Disorder as an Epiphenomenon of Comorbid Bipolar Disorder? An Updated Systematic Review.

BACKGROUND: Bipolar disorder (BD) and obsessive-compulsive disorder (OCD) comorbidity is an emerging condition in psychiatry, with relevant nosological, clinical, and therapeutic implications. METHODS: We updated our previous systematic review on epidemiology and standard diagnostic validators (including phenomenology, course of illness, heredity, biological markers, and treatment response) of BD-OCD. Relevant papers published until (and including) 15 October 2023 were identified by searching the electronic databases MEDLINE, Embase, PsychINFO, and Cochrane Library, according to the PRISMA statement (PROSPERO registration number, CRD42021267685). RESULTS: We identified 38 new articles, which added to the previous 64 and raised the total to 102. The lifetime comorbidity prevalence ranged from 0.26 to 27.8% for BD and from 0.3 to 53.3% for OCD. The onset of the two disorders appears to be often overlapping, although the appearance of the primary disorder may influence the outcome. Compared to a single diagnosis, BD-OCD exhibited a distinct pattern of OC symptoms typically following an episodic course, occurring in up to 75% of cases (vs. 3%). Notably, these OC symptoms tended to worsen during depressive episodes (78%) and improve during manic or hypomanic episodes (64%). Similarly, a BD course appears to be chronic in individuals with BD-OCD in comparison to patients without. Additionally, individuals with BD-OCD comorbidity experienced more depressive episodes (mean of 8.9 ± 4.2) compared to those without comorbidity (mean of 4.1 ± 2.7). CONCLUSIONS: We found a greater likelihood of antidepressant-induced manic/hypomanic episodes (60% vs. 4.1%), and mood stabilizers with antipsychotic add-ons emerging as a preferred treatment. In line with our previous work, BD-OCD comorbidity encompasses a condition of greater nosological and clinical complexity than individual disorders.

Early-onset obsessive-compulsive disorder: Sociodemographic and clinical characterization of a large outpatient cohort.

INTRODUCTION: Obsessive-compulsive disorder (OCD) is a prevalent and disabling condition characterized by a wide variety of phenotypic expressions. Several studies have reinforced the hypothesis of OCD heterogeneity by proposing subtypes based on predominant symptomatology, course, and comorbidities. Early-onset OCD (EO) could be considered a neurodevelopmental subtype of OCD, with evidence of distinct neurocircuits supporting disease progression. To deepen the heterogeneous nature of the disorder, we analyzed sociodemographic and clinical differences between the EO and late-onset (LO) subtypes in a large outpatient cohort. METHODS: Two hundred and eighty-four patients diagnosed with OCD were consecutively recruited from the OCD Tertiary Clinic at Luigi Sacco University Hospital in Milan. Sociodemographic and clinical variables were analyzed for the entire sample and compared between the two subgroups (EO, age <18 years [n = 117,41.2 %]; LO: late-onset, age ≥18 years [n = 167, 58.8 %]). RESULTS: The EO group showed a higher frequency of male gender (65 % vs 42.5 %, p < .001), and a higher prevalence of Tic and Tourette disorders (9.4 % vs 0 %, p < .001) compared to the LO group. Additionally, in the EO subgroup, a longer duration of untreated illness was observed (9.01 ± 9.88 vs 4.81 ± 7.12; p < .001), along with a lower presence of insight (13.8 % vs. 7.5 %, p < .05). CONCLUSIONS: The early-onset OCD subtype highlights a more severe clinical profile compared to the LO group. Exploring distinct manifestations and developmental trajectories of OCD can contribute to a better definition of homogeneous subtypes, useful for defining targeted therapeutic strategies for treatment.

Selective alterations of endocannabinoid system genes expression in obsessive compulsive disorder.

Obsessive Compulsive Disorder (OCD) is listed as one of the top 10 most disabling neuropsychiatric conditions in the world. The neurobiology of OCD has not been completely understood and efforts are needed in order to develop new treatments. Beside the classical neurotransmitter systems and signalling pathways implicated in OCD, the possible involvement of the endocannabinoid system (ECS) has emerged in pathophysiology of OCD. We report here selective downregulation of the genes coding for enzymes allowing the synthesis of the endocannabinoids. We found reduced DAGLα and NAPE-PLD in blood samples of individuals with OCD (when compared to healthy controls) as well as in the amygdala complex and prefrontal cortex of dopamine transporter (DAT) heterozygous rats, manifesting compulsive behaviours. Also mRNA levels of the genes coding for cannabinoid receptors type 1 and type 2 resulted downregulated, respectively in the rat amygdala and in human blood. Moreover, NAPE-PLD changes in gene expression resulted to be associated with an increase in DNA methylation at gene promoter, and the modulation of this gene in OCD appears to be correlated to the progression of the disease. Finally, the alterations observed in ECS genes expression appears to be correlated with the modulation in oxytocin receptor gene expression, consistently with what recently reported. Overall, we confirm here a role for ECS in OCD at both preclinical and clinical level. Many potential biomarkers are suggested among its components, in particular NAPE-PLD, that might be of help for a prompt and clear diagnosis.

Climate Change Perception and Mental Health. Results from a Systematic Review of the Literature.

Climate change is one of the main global challenges and influences various aspects of human health. Numerous studies have indeed demonstrated an association between extreme climate-related events and physical and mental health outcomes, but little is still known about the association between the perception/awareness of climate change and mental health. In accordance with the PRISMA 2020 guidelines, a search was conducted on PubMed and Scopus. The protocol was registered on PROSPERO. The included studies were original observational studies published in English, reporting the association between the perception/awareness of climate change and mental health. A total of 3018 articles were identified. A total of 10 observational studies were included. The period covered in the included studies ranged between 2012 and 2022. Climate change perception is consistently associated with adverse mental health effects across different types of estimates. In particular, the studies identified an association between a higher level of perception/awareness of climate change and depression, anxiety, eco-anxiety, stress, adjustment disorder, substance use, dysphoria, and even thoughts of suicide. Qualitative data underscore the impact on daily activities, contributing to feelings of loss and suicidal ideation. Moreover, climate change perception correlates with lower well-being and resilience. The association between awareness of climate change and mental health is a complex and still poorly explored phenomenon. The main limitations are the high heterogeneity in terms of exposure assessment and data reporting, which hinders quantitative analysis. These results show that climate change perception impacts mental health. Better understanding the phenomenon represents an opportunity to inform public health interventions that promote mental well-being.

Lessons from a multicenter, international, large sample size analysis of patients with obsessive-compulsive disorders: an overview of the ICOCS Snapshot studies.

Obsessive-compulsive disorder (OCD) is a prevalent and highly disabling condition, characterized by a range of phenotypic expressions, potentially associated with geo-cultural differences. This article aims to provide an overview of the published studies by the International College of Obsessive-Compulsive Spectrum Disorders, in relation to the Snapshot database which has, over the past 10 years, gathered clinical naturalistic data from over 500 patients with OCD attending various research centers/clinics worldwide. This collaborative effort has provided a multi-cultural worldwide perspective of different socio-demographic and clinical features of patients with OCD. Data on age, gender, smoking habits, age at onset, duration of illness, comorbidity, suicidal behaviors, and pharmacological treatment strategies are presented here, showing peculiar differences across countries.

Mild internet use is associated with epigenetic alterations of key neurotransmission genes in salivary DNA of young university students.

The potentially problematic use of the Internet is a growing concern worldwide, which causes and consequences are not completely understood yet. The neurobiology of Internet addiction (IA) has attracted much attention in scientific research, which is now focusing on identifying measurable biological markers. Aim of this study was to investigate epigenetic and genetic regulation of oxytocin receptor (OXTR), dopamine transporter (DAT1) and serotonin transporter (SERT) genes using DNA obtained from saliva samples of young university students: the Internet Addiction Test (IAT) was administered to evaluate the potential existence and intensity of IA. Significant changes in DNA methylation levels at OXTR, DAT1 and SERT genes were observed in the 30 < IAT < 49 group (mild-risk internet users) compared to the IAT < 29 subjects (complete control of internet use) and IAT > 50 subjects (considered as moderately addicted). Moreover, epigenetic markers were significantly correlated, either directly (for OXTR and DAT1) or inversely (OXTR and DAT1 versus SERT), to the psychometric properties. Our data confirmed the association of OXTR, DAT1 and SERT genes in processes related to behavioural addictions and might be of relevance to suggest possible biological predictors of altered behaviours and the eventual vulnerability to develop an IA. Different other genetic pathways have been suggested to play a role in IA and research is ongoing to better define them, in order to help in the early diagnosis as well as in the development of new potential treatments.

A possible role for G-quadruplexes formation and DNA methylation at IMOOD gene promoter in Obsessive Compulsive Disorder.

Obsessive Compulsive Disorder (OCD) is a mental health condition still classified and diagnosed with subjective interview-based assessments and which molecular clues have not completely been elucidated. We have recently identified a new regulator of anxiety and OCD-like behavior called Immuno-moodulin (IMOOD) and, here, we report that IMOOD gene promoter is differentially methylated in OCD subjects when compared to genomic material collected from healthy controls and this alteration is significantly correlated with the increased expression of the gene in OCD. We also demonstrated that IMOOD promoter can form G-quadruplexes and we suggest that, in homeostatic conditions, these structures could evoke DNA-methylation silencing the gene, whereas in pathological conditions, like OCD, could induce gene expression making the promoter more accessible to transcriptional factors. We here thus further suggest IMOOD as a new biomarker for OCD and also hypothesize new mechanisms of gene regulation.

Partial Response to Antidepressant Treatment: The Role of Nutraceutical Compounds.

Objective: Depression represents one of the most severe psychiatric disorders, characterized by low mood episodes, as well as loss of interest. Major Depressive Episodes (MDE) treatment relies primarily on monoaminergic prescriptions. However, although the presence of many antidepressant medications, their efficacy is still partial. A promising intervention to improve antidepressant treatment may be the use of adjunctive nutraceuticals. Aim of the present study was to assess the efficacy of a N-Acetyl-cysteine, S-Adenosyl-L-Methionine and Folic acid's combination for the treatment of depressive symptoms in a sample of MDE patients. Method: Fifty outpatients with a MDE diagnosis in the context of different psychiatric disorders such as Major Depression, Bipolar Disorder, Anxiety disorders, and Personality disorders were recruited. The sample was divided into different groups based on the nutraceutical administration: a) concurrently with an AD (starter group); b) add-on to an already prescribed treatment; c) single treatment. Results: A significant reduction of CGI-Severity and Improvement scores from baseline to the end of treatment was found. Moreover, the starter group showed a significantly greater CGI-Improvement score compared to the other groups. Ninety-four percent of patients did not show any side effects. Conclusions: The present study showed promising results for the use of nutraceuticals in the add-on treatment of MDE. Those compounds may be considered a versatile, tolerable, and effective add-on treatment for the reduction of depressive symptoms impact and for improving the functioning of patients affected by MDE.

The potential effect of metformin on cognitive and other symptom dimensions in patients with schizophrenia and antipsychotic-induced weight gain: a systematic review, meta-analysis, and meta-regression.

Introduction: Metformin has shown good efficacy in the management of antipsychotic-induced metabolic syndrome (MetS) in patients with schizophrenia or schizoaffective disorders. Its ability to induce antidepressant behavioural effects and improve cognitive functions has also been investigated: yet information has not been systematized. The aim of this study was therefore to investigate the effects of metformin on cognitive and other symptom dimension in schizophrenic patients treated with antipsychotics through a systematic review and meta-analysis. Methods: We searched PubMed, ClinicalTrials.Gov, Embase, PsycINFO, and WHO ICTRP database up to February 2022, Randomised Controlled Trials (RCT) evaluating patients diagnosed with schizophrenia and related disorders, who were treated with metformin as add-on therapy to antipsychotics for the treatment of weight gain and in which changes in psychiatric symptoms and cognitive functions were evaluated. Results: A total of 19 RCTs met the inclusion criteria. Meta-analysis was performed on 12 eligible studies. We found a positive trend after 24 weeks of treatment in schizophrenic patients with stable conditions [SMD (95%CI) = -0.40 (-0.82;0.01), OR (95%CI) = 0.5 (-2.4;3.4)]. Better performance was detected in the Brief Assessment of Cognition in Schizophrenia and Positive and Negative Syndrome Scale (PANSS) with low heterogeneity among studies. One study reported changes in BACS-verbal memory subdomain in favour of placebo [MD (95%CI) = -16.03 (-23.65;8.42)]. Gastrointestinal disorders, xerostomia, and extrapyramidal syndrome were the most reported adverse effects. Psychiatric adverse events were also described: in particular, symptoms attributable to a relapse of schizophrenia. Conclusion: Some degree of efficacy was found for Metformin in improving cognitive and other symptom dimensions in patients with Schizophrenia. Given the clinical relevance of this potential pharmacological effect, longer specific studies using adequate psychometric scales are strongly recommended. Likewise, how metformin acts in this context needs to be evaluated in order to enhance its efficacy or find more efficacious drugs.

Psychiatric and non-psychiatric drugs causing false-positive amphetamines urine test in psychiatric patients: a pharmacovigilance analysis using FAERS.

INTRODUCTION: Immunoassay urine drug screen (UDS) is frequently used in clinical practice for initial screening process, being generally available, fast, and inexpensive. Exposure to widely prescribed drugs might determine false-positive UDS amphetamines, leading to diagnostic issues, wrong therapeutic choices, impairment of physician-patient relationship, and legal implications. AREAS COVERED: To summarize and comment on a comprehensive list of compounds responsible for UDS false positives for amphetamines, we conducted a literature review on PubMed along with a comparison with Real-World Data from the Food and Drug Administration Adverse Event Reporting System (FAERS) database analysis between 2010 and 2022. Forty-four articles and 125 Individual Case Safety Reports (ICSR) involving false-positive amphetamine UDS in psychiatric patients were retrieved from FAERS. EXPERT OPINION: False-positive results were described in literature for antidepressants, atomoxetine, methylphenidate, and antipsychotics, but also for non-psychiatric drugs of common use, such as labetalol, fenofibrate, and metformin. Immunoassay method is usually responsible for false-positive results, and in most cases, mass spectrometry (MS) does not eventually confirm the UDS positivity. Physicians should be aware of immunoassays' limitations and when turning to a confirmatory test. Any new cross-reaction should be reported to pharmacovigilance activities.

Gender impact on the outcome of rehabilitation programs in psychiatry: Brief report from a metropolitan residential rehabilitative service.

Background: Differences based on gender in the presentation and outcome of many psychiatric conditions have been highlighted in the past years. Moreover, women are often underrepresented in research samples, thus leading to a poorer understanding and addressing of their needs. As regards psychiatric rehabilitation, few studies have focused on the influence of gender on the outcomes of rehabilitation programs. Objectives: This study aimed to analyze the impact of gender on socio-demographic and clinical characteristics, as well as on main rehabilitation outcomes, in a sample of subjects undergoing rehabilitation programs in a metropolitan residential service. Methods: We collected socio-demographic, clinical variables and rehabilitation outcomes of all subjects discharged from the metropolitan residential rehabilitative service of the Luigi Sacco Hospital in Milan, Italy, from January 2015 to December 2021. Gender differences were analyzed through t-test and chi-square for continuous and categorical variables, respectively. Results: In a total sample of 129 subjects equally distributed for gender (50.4% women), all subjects improved after their rehabilitation program, as measured through specific psychometric scales. However, women had a higher proportion of discharges to their own household (52.3% vs. 25% of men). They also showed higher educational status (53.8% completed high school vs. 31.3% of men). Clinically, they showed longer duration of untreated illness (3.6 ± 7.31 vs. 1.06 ± 2.35 years) and lower frequency of substance use disorders compared to men (6.4% vs. 35.9%). Conclusion: The main result of this study shows, in light of an equal improvement in psychopathological and psychosocial functioning after the rehabilitation program, better outcomes in women compared to men, with a higher frequency of return to their own household after the completion of a rehabilitation program compared to men.

Intensive Neurofeedback Protocol: An Alpha Training to Improve Sleep Quality and Stress Modulation in Health Care Professionals During the Covid-19 Pandemic. A Pilot Study.

Objective: health care workers (HCWs) represent a vulnerable group in the COVID-19 pandemic, given the exposure to greater risk and higher levels of work-related stress. Neurofeedback (NF) has shown to be effective in the treatment of stress-related symptoms. We aimed to assess the effectiveness of an alpha-increase NF protocol for the treatment of acute stress symptoms in HCWs exposed to the COVID-19 pandemic. Method: eighteen medical doctors on duty during the COVID-19 health emergency underwent an intensive NF alpha-increase protocol. The mean alpha wave values were recorded at the beginning (T0) and at the last day of stimulation (T1). Rapid Stress Assessment: Italian version; Copenhagen Burnout Inventory (CBI); Pittsburgh Sleep Quality Index (PSQI), and Brief-COPE were administered as psychometric assessment. Results: a significant increase in alpha wave values and a significant reduction of the PSQI scores from T0 to T1 were found. Conclusions: NF alpha-increase protocol showed promising results in terms of stress modulation, sleep quality improvement, and safety in a pilot sample of HCWs.

The Role of Lifestyle on Adherence to Treatment in a Sample of Patients with Unipolar and Bipolar Depression.

Introduction: Poor adherence to treatment is currently stated to be one of the causes of depression relapse and recurrence. The aim of the present study is to assess potential differences in terms of clinical and lifestyle features related to adherence to treatment in a sample of patients with unipolar and bipolar depression. Methods: One hundred and eight patients with a diagnosis of unipolar or bipolar depressive episode were recruited from January 2021 to October 2022. Adherence to psychopharmacological treatment was assessed using the clinician rating scale. Descriptive and association analyses were performed to compare subgroups based on adherence to treatment. Results: Lower levels of adherence to treatment were associated with fewer years of education, work impairment, manic prevalent polarity lifetime, and greater comorbidity with alcohol and drug abuse. The majority of patients with positive adherence did not report any hospitalization and involuntary commitment lifetime. Conclusions: Patients with a positive treatment adherence showed significant differences in terms of lifestyle and clinical features compared to non-adherent patients. Our results may help to identify patients more likely to have poor medication adherence, which seem to lead to a worse disease course and quality of life.

Cognitive functioning as predictor and marker of response to repetitive transcranial magnetic stimulation in depressive disorders: A systematic review.

OBJECTIVE: Cognitive performance in Major Depressive Disorder (MDD) is frequently impaired and related to functional outcomes. Repetitive Transcranial Magnetic Stimulation (rTMS) may exert its effects on MDD acting both on depressive symptoms and neurocognition. Furthermore, cognitive status could predict the therapeutic response of depressive symptoms to rTMS. However, cognitive performances as a predictor of rTMS response in MDD has not been thoroughly investigated. This review aims to evaluate the role of pre-treatment cognitive performance as a predictor of clinical response to rTMS, and the effects of rTMS on neurocognition in MDD. METHOD: A systematic review of studies evaluating neurocognition in MDD as an outcome and/or predictor of response to rTMS was conducted using PubMed/Medline and Embase. RESULTS: Fifty-eight articles were identified: 25 studies included neurocognition as a predictor of response to rTMS; 56 used cognitive evaluation as an outcome of rTMS. Baseline cognitive performance and cognitive improvements after rTMS predicted clinical response to rTMS. Moreover, rTMS improved cognition in MDD. CONCLUSIONS: Cognitive assessment could predict improvement of depression in MDD patients undergoing rTMS and help selecting patients that could have beneficial effects from rTMS. A routine cognitive assessment might stratify MDD patients and track rTMS related cognitive improvement.

Possible Use of Minocycline in Adjunction to Intranasal Esketamine for the Management of Difficult to Treat Depression following Extensive Pharmacogenomic Testing: Two Case Reports.

The advent of intra-nasal esketamine (ESK), one of the first so called fast-acting antidepressant, promises to revolutionize the management of treatment resistant depression (TRD). This NMDA receptor antagonist has proven to be rapidly effective in the short- and medium-term course of the illness, revealing its potential in targeting response in TRD. Although many TRD ESK responders are able to achieve remission, a considerable portion of them undergo a metamorphosis of their depression into different clinical presentations, characterized by instable responses and high recurrence rates that can be considered closer to the concept of Difficult to Treat Depression (DTD) than to TRD. The management of these DTD patients usually requires a further complex multidisciplinary approach and can benefit from the valuable contribution of new personalized medicine tools such as therapeutic drug monitoring and pharmacogenetics. Despite this, these patients usually come with long and complex previous treatments history and, often, advanced and sophisticated ongoing pharmacological schemes that can make the finding of new alternative options to face the current recurrences extremely challenging. In this paper, we describe two DTD patients-already receiving intranasal ESK but showing an instable course-who were clinically stabilized by the association with minocycline, a semisynthetic second-generation tetracycline with known and promising antidepressant properties.

Cannabis use and related clinical variables in patients with obsessive-compulsive disorder.

OBJECTIVE: Limited studies have investigated cannabis use in patients with obsessive-compulsive disorder (OCD), despite its widespread use by patients with psychiatric illnesses. The aim of this study was to assess the frequency, correlates, and clinical impact of cannabis use in an Italian sample of patients with OCD. METHODS: Seventy consecutive outpatients with OCD were recruited from a tertiary specialized clinic. To assess cannabis-related variables, patients completed a questionnaire developed for the purpose of this study, investigating cannabis use-related habits and the influence of cannabis use on OCD symptoms and treatments. A set of clinician and self-reported questionnaires was administered to measure disease severity. The sample was then divided into three subgroups according to the pattern of cannabis use: "current users" (CUs), "past-users" (PUs), and "non-users" (NUs). RESULTS: Approximately 42.8% of patients reported lifetime cannabis use and 14.3% reported current use. Approximately 10% of cannabis users reported an improvement in OCD symptoms secondary to cannabis use, while 23.3% reported an exacerbation of anxiety symptoms. CUs showed specific unfavorable clinical variables compared to PUs and NUs: a significant higher rate of lifetime use of tobacco, alcohol, and other substances, and a higher rate of pre-OCD onset comorbidities. Conversely, the three subgroups showed a similar severity of illness. CONCLUSION: A considerable subgroup of patients with OCD showed a predisposition towards cannabis use and was associated with some specific clinical characteristics, suggesting the need for targeted consideration and interventions in this population.

First vs second wave of COVID-19 pandemic in patients with obsessive compulsive disorder: A multicentre report from tertiary clinics in Northern Italy.

INTRODUCTION: Among patients with mental illness, those with obsessive compulsive disorder (OCD) showed a significant clinical worsening by the COVID-19 pandemic. The effects of the COVID-19 pandemic on OCD have been shown to worsen symptoms severity, with serious clinical consequences. However, the persistence of COVID-19 pandemic in OCD patients has been poorly investigated. The purpose of the present study was to assess the impact of the second wave of the COVID-19 pandemic in a sample of OCD patients and to compare the results with those obtained during the first wave on the same OCD sample. METHODS: 116 OCD outpatients attending three OCD tertiary clinics in Northern Italy and previously included in a report on the impact of COVID-19, were followed-up in order to investigate sociodemographic and clinical features. Appropriate statistical analyses for categorical and continuous variables were conducted. RESULTS: The 43 OCD patients with a clinical worsening (OW) reported a significant development of new obsessions/compulsions and the recurrence of past OC symptoms, higher rates of psychiatric comorbidities and sleep disturbances compared to patients without symptom worsening. Moreover, an increase in avoidance behaviors, suicidal ideation, Internet checking for reassurance, and job difficulties emerged in OW patients. Also, lower rates of pharmacological stability, and higher rates of therapy adjustment were observed. In terms of sex differences, males showed higher rates of past obsessions occurrence, while females showed a rise in Internet checking behaviors. When comparing OW patients between the first and the second wave, the latter showed significantly higher rates of past obsession occurrence and lower rates of pharmacological stability. Moreover, patients with OW showed a significantly older age during the second wave. CONCLUSION: The persistence of the COVID-19 pandemic showed a globally impaired clinical picture in the analyzed OCD sample. A further worsening between the two waves timepoints emerged, mainly involving older patients with OCD. The concordance between our results and those existing in literature highlights the importance of an accurate long-term monitoring of OCD patients in light of COVID-19 pandemic persistence.

Advances in problematic usage of the internet research - A narrative review by experts from the European network for problematic usage of the internet.

Global concern about problematic usage of the internet (PUI), and its public health and societal costs, continues to grow, sharpened in focus under the privations of the COVID-19 pandemic. This narrative review reports the expert opinions of members of the largest international network of researchers on PUI in the framework of the European Cooperation in Science and Technology (COST) Action (CA 16207), on the scientific progress made and the critical knowledge gaps remaining to be filled as the term of the Action reaches its conclusion. A key advance has been achieving consensus on the clinical definition of various forms of PUI. Based on the overarching public health principles of protecting individuals and the public from harm and promoting the highest attainable standard of health, the World Health Organisation has introduced several new structured diagnoses into the ICD-11, including gambling disorder, gaming disorder, compulsive sexual behaviour disorder, and other unspecified or specified disorders due to addictive behaviours, alongside naming online activity as a diagnostic specifier. These definitions provide for the first time a sound platform for developing systematic networked research into various forms of PUI at global scale. Progress has also been made in areas such as refining and simplifying some of the available assessment instruments, clarifying the underpinning brain-based and social determinants, and building more empirically based etiological models, as a basis for therapeutic intervention, alongside public engagement initiatives. However, important gaps in our knowledge remain to be tackled. Principal among these include a better understanding of the course and evolution of the PUI-related problems, across different age groups, genders and other specific vulnerable groups, reliable methods for early identification of individuals at risk (before PUI becomes disordered), efficacious preventative and therapeutic interventions and ethical health and social policy changes that adequately safeguard human digital rights. The paper concludes with recommendations for achievable research goals, based on longitudinal analysis of a large multinational cohort co-designed with public stakeholders.