Collaborative outcomes study on health and functioning during infection times (COH-FIT): Insights on modifiable and non-modifiable risk and protective factors for wellbeing and mental health during the COVID-19 pandemic from multivariable and network analyses.

There is no multi-country/multi-language study testing a-priori multivariable associations between non-modifiable/modifiable factors and validated wellbeing/multidimensional mental health outcomes before/during the COVID-19 pandemic. Moreover, studies during COVID-19 pandemic generally do not report on representative/weighted non-probability samples. The Collaborative Outcomes study on Health and Functioning during Infection Times (COH-FIT) is a multi-country/multi-language survey conducting multivariable/LASSO-regularized regression models and network analyses to identify modifiable/non-modifiable factors associated with wellbeing (WHO-5)/composite psychopathology (P-score) change. It enrolled general population-representative/weighted-non-probability samples (26/04/2020-19/06/2022). Participants included 121,066 adults (age=42±15.9 years, females=64 %, representative sample=29 %) WHO-5/P-score worsened (SMD=0.53/SMD=0.74), especially initially during the pandemic. We identified 15 modifiable/nine non-modifiable risk and 13 modifiable/three non-modifiable protective factors for WHO-5, 16 modifiable/11 non-modifiable risk and 10 modifiable/six non-modifiable protective factors for P-score. The 12 shared risk/protective factors with highest centrality (network-analysis) were, for non-modifiable factors, country income, ethnicity, age, gender, education, mental disorder history, COVID-19-related restrictions, urbanicity, physical disorder history, household room numbers and green space, and socioeconomic status. For modifiable factors, we identified medications, learning, internet, pet-ownership, working and religion as coping strategies, plus pre-pandemic levels of stress, fear, TV, social media or reading time, and COVID-19 information. In multivariable models, for WHO-5, additional non-modifiable factors with |B|>1 were income loss, COVID-19 deaths. For modifiable factors we identified pre-pandemic levels of social functioning, hobbies, frustration and loneliness, and social interactions as coping strategy. For P-scores, additional non-modifiable/modifiable factors were income loss, pre-pandemic infection fear, and social interactions as coping strategy. COH-FIT identified vulnerable sub-populations and actionable individual/environmental factors to protect well-being/mental health during crisis times. Results inform public health policies, and clinical practice.

Naturalistic psychedelic therapy: The role of relaxation and subjective drug effects in antidepressant response.

BACKGROUND: Psychedelic-assisted therapy (PAT) is permitted in Switzerland under its limited medical use program. Data from patients in this program represent a unique opportunity to analyze the real-world practice of PAT. AIMS: This study compared the subjective effects of lysergic acid diethylamide (LSD) and psilocybin between patients undergoing PAT and healthy volunteers. For the patients, it also investigated the relationship between antidepressant effects and six measures of acute drug effects. METHODS: We compared data on acute psychedelic drug effects between 28 PAT patients with data from 28 healthy participants who participated in a randomized, double-blind crossover trial. All participants received varying doses of psilocybin and LSD. Subjective effects were assessed on an hourly basis during the acute drug effects, and the Mystical Experience Questionnaire (MEQ) was completed retrospectively. For patients, depressive symptoms were assessed using the Montgomery-Åsberg Depression Rating Scale (MADRS). RESULTS: Ratings of overall drug effect and mystical experience were similar across groups. Compared with healthy controls, patients reported lower ratings of ego dissolution. Patients showed a significant decrease in MADRS scores, and the greatest predictor of antidepressant outcome was relaxation during the PAT session. We did not observe a relationship between mystical-type experiences and antidepressant effects. Most patients experienced mild adverse effects which resolved within 48 h. CONCLUSION: PAT reduced depressive symptoms in this heterogeneous patient group. Patients may experience more challenging psychedelic effects and reduced ego dissolution. Hourly assessment of drug effects may predict clinical outcomes better than retrospectively assessed mystical experiences, and the impact of relaxation during PAT should be investigated further.

Global and risk-group stratified well-being and mental health during the COVID-19 pandemic in adults: Results from the international COH-FIT Study.

International studies measuring wellbeing/multidimensional mental health before/ during the COVID-19 pandemic, including representative samples for >2 years, identifying risk groups and coping strategies are lacking. COH-FIT is an online, international, anonymous survey measuring changes in well-being (WHO-5) and a composite psychopathology P-score, and their associations with COVID-19 deaths/restrictions, 12 a-priori defined risk individual/cumulative factors, and coping strategies during COVID-19 pandemic (26/04/2020-26/06/2022) in 30 languages (representative, weighted non-representative, adults). T-test, χ2, penalized cubic splines, linear regression, correlation analyses were conducted. Analyzing 121,066/142,364 initiated surveys, WHO-5/P-score worsened intra-pandemic by 11.1±21.1/13.2±17.9 points (effect size d=0.50/0.60) (comparable results in representative/weighted non-probability samples). Persons with WHO-5 scores indicative of depression screening (<50, 13% to 32%) and major depression (<29, 3% to 12%) significantly increased. WHO-5 worsened from those with mental disorders, female sex, COVID-19-related loss, low-income country location, physical disorders, healthcare worker occupations, large city location, COVID-19 infection, unemployment, first-generation immigration, to age=18-29 with a cumulative effect. Similar findings emerged for P-score. Changes were significantly but minimally related to COVID-19 deaths, returning to near-pre-pandemic values after >2 years. The most subjectively effective coping strategies were exercise and walking, internet use, social contacts. Identified risk groups, coping strategies and outcome trajectories can inform global public health strategies.

Emerging Perspectives on Neuroprotection.

Neuroprotection aims to safeguard neurons from damage caused by various factors like stress, potentially leading to the rescue, recovery, or regeneration of the nervous system and its functions [J Clin Neurosci. 2002;9(1):4-8]. Conversely, neuroplasticity refers to the brain's ability to adapt and change throughout life, involving structural and functional alterations in cells and synaptic transmission [Neural Plast. 2014;2014:541870]. Neuroprotection is a broad and multidisciplinary field encompassing various approaches and strategies aimed at preserving and promoting neuronal health. It is a critical area of research in neuroscience and neurology, with the potential to lead to new therapies for a wide range of neurological disorders and conditions. Neuroprotection can take various forms and may involve pharmacological agents, lifestyle modifications, or behavioral interventions. Accordingly, also the perspective and the meaning of neuroprotection differs due to different angles of interpretation. The primary interpretation is from the pharmacological point of view since the most consistent data come from this field. In addition, we will discuss also alternative, yet less considered, perspectives on neuroprotection, focusing on specific neuroprotective targets, interactions with surrounding microglia, different levels of neuroprotective effects, the reversive/adaptative dimension, and its use as anticipatory/prophylactic intervention.

Validation of the Swiss Psychedelic Side Effects Inventory: Standardized assessment of adverse effects in studies of psychedelics and MDMA.

INTRODUCTION: Studies of psychedelic-assisted therapy with LSD, psilocybin, MDMA, and related substances show clinical promise but inadequately assess side effects. Measuring side effects is challenging because they are not always easily differentiated from treatment effects or disease symptoms and show high heterogeneity, variable duration and impact, and sensitivity to context. A systematic questionnaire describing important characteristics of side effects of psychedelics and MDMA would greatly improve on previous methods. We aimed to create a standardized tool for recording clinically relevant side effects of psychedelics and MDMA, including their severity, duration, impact, and treatment-relatedness. METHODS: We constructed the Swiss Psychedelic Side Effects Inventory (SPSI) based on insights from previous research. It was pilot tested in 145 participants from three studies. Structured feedback from an expert panel was used to improve validity and feasibility. RESULTS: The final SPSI contains 32 side effects and standardized follow-up questions about their severity, impact, treatment-relatedness, and duration. It is compatible with any study design and can be administered as an interview or self-report at any timepoint after treatment with psychedelics or MDMA. LIMITATIONS: The SPSI omits relatively unimportant side effects for brevity's sake, though space for additional symptoms is given. Future studies are needed to confirm its validity in different contexts. CONCLUSIONS: The SPSI is available in English and German for collecting systematic data on side effects from psychedelics and MDMA. This information is vital for improving clinical decisions, informed consent, and patient safety.

Human endogenous retroviruses type W (HERV-) activation and schizophrenia: A meta-analysis.

OBJECTIVE: Human endogenous retroviruses (HERV) are the remnants of infections that occurred million years ago. They gradually integrated into the human genome, comprising 8 % of it. There are growing reports suggesting their potential role in various diseases, including schizophrenia. Schizophrenia, a serious psychiatric disorder, is caused by the interaction of genetic and environmental factors. In the present paper, we investigated studies focusing on the association between schizophrenia and HERV-W. METHODS: We registered this study at PROSPERO (registration number: CRD42022301122). The entire steps of this study were based on the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. We searched PubMed, Scopus, Web of Science, and Google Scholar up to 1 August 2022. Heterogeneity was estimated through I2 statistics, and the association was measured using the first estimate and penalization methods. RESULTS: Finally, 13 eligible studies were analyzed, including 698 cases and 728 controls. The overall odds ratio indicated a significant association in both the first estimate (OR = 9.34, 95 % CI = 4.92-17.75; P = 0.002) and penalization (OR = 7.38, 95 % CI = 4.15-13.10; P = 0.003) methods. In the subgroup analysis, among HERV-W fragments, the HERV-W envelope protein or RNA (OR = 11.41, 95 % CI: 5.67-22.97; P = 0.03) showed the strongest association with schizophrenia. CONCLUSION: Our meta-analysis showed that HERV-W is significantly associated with schizophrenia. More studies are required to determine the pathophysiological mechanism and the diagnostic, prognostic, and therapeutic value of HERV-W in schizophrenia.

Efficacy and safety of established and off-label ADHD drug therapies for cognitive impairment or attention-deficit hyperactivity disorder symptoms in bipolar disorder: A systematic review by the ISBD Targeting Cognition Task Force.

BACKGROUND: Abnormalities in dopamine and norepinephrine signaling are implicated in cognitive impairments in bipolar disorder (BD) and attention-deficit hyperactivity disorder (ADHD). This systematic review by the ISBD Targeting Cognition Task Force therefore aimed to investigate the possible benefits on cognition and/or ADHD symptoms and safety of established and off-label ADHD therapies in BD. METHODS: We included studies of ADHD medications in BD patients, which involved cognitive and/or safety measures. We followed the procedures of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) 2020 statement. Searches were conducted on PubMed, Embase and PsycINFO from inception until June 2023. Two authors reviewed the studies independently using the Revised Cochrane Collaboration's Risk of Bias tool for Randomized trials. RESULTS: Seventeen studies were identified (N = 2136), investigating armodafinil (k = 4, N = 1581), methylphenidate (k = 4, N = 84), bupropion (k = 4, n = 249), clonidine (k = 1, n = 70), lisdexamphetamine (k = 1, n = 25), mixed amphetamine salts (k = 1, n = 30), or modafinil (k = 2, n = 97). Three studies investigated cognition, four ADHD symptoms, and 10 the safety. Three studies found treatment-related ADHD symptom reduction: two involved methylphenidate and one amphetamine salts. One study found a trend towards pro-cognitive effects of modafinil on some cognitive domains. No increased risk of (hypo)mania was observed. Five studies had low risk of bias, eleven a moderate risk, and one a serious risk of bias. CONCLUSIONS: Methylphenidate or mixed amphetamine salts may improve ADHD symptoms in BD. However, there is limited evidence regarding the effectiveness on cognition. The medications produced no increased mania risk when used alongside mood stabilizers. Further robust studies are needed to assess cognition in BD patients receiving psychostimulant treatment alongside mood stabilizers.

Microdosing psychedelics and the risk of cardiac fibrosis and valvulopathy: Comparison to known cardiotoxins.

Though microdosing psychedelics has become increasingly popular, its long-term effects on cardiac health remain unknown. Microdosing most commonly involves ingesting sub-threshold doses of lysergic acid diethylamide (LSD), psilocybin, or other psychedelic drugs 2-4 times a week for at least several weeks, but potentially months or years. Concerningly, both LSD and psilocybin share structural similarities with medications which raise the risk of cardiac fibrosis and valvulopathy when taken regularly, including methysergide, pergolide, and fenfluramine. 3,4-Methylenedioxymethamphetamine, which is also reportedly used for microdosing, is likewise associated with heart valve damage when taken chronically. In this review, we evaluate the evidence that microdosing LSD, psilocybin, and other psychedelics for several months or more could raise the risk of cardiac fibrosis. We discuss the relationship between drug-induced cardiac fibrosis and the 5-HT2B receptor, and we make recommendations for evaluating the safety of microdosing psychedelics in future studies.

Prefrontal Glutathione Levels in Major Depressive Disorder Are Linked to a Lack of Positive Affect.

Major depressive disorder (MDD) is one of the most common neuropsychiatric disorders, with symptoms including persistent sadness and loss of interest. MDD is associated with neurochemical alterations in GABA, glutamate, and glutamine levels but, to date, few studies have examined changes in glutathione (GSH) in MDD. This study investigated changes in GSH in an unmedicated group of young adults, including 46 participants with current (n = 12) or past MDD (n = 34) and 20 healthy controls. Glutathione levels were assessed from GSH-edited magnetic resonance (MR) spectra, acquired from a voxel in the left prefrontal cortex, and depressive symptoms were evaluated with validated questionnaires and clinical assessments. Cortisol levels were also assessed as a marker for acute stress. Participants with current MDD demonstrated elevated GSH in comparison to participants with past MDD and controls, although the results could be influenced by differences in tissue composition within the MRS voxel. In addition, participants with both current and past MDD showed elevated cortisol levels in comparison to controls. No significant association was observed between GSH and cortisol levels, but elevated GSH levels were associated with a decrease in positive affect. These results demonstrate for the first time that elevated GSH in current but not past depression may reflect a state rather than a trait neurobiological change, related to a loss of positive affect.

Controversies regarding lithium-associated weight gain: case-control study of real-world drug safety data.

BACKGROUND: The impact of long-term lithium treatment on weight gain has been a controversial topic with conflicting evidence. We aim to assess reporting of weight gain associated with lithium and other mood stabilizers compared to lamotrigine which is considered free of metabolic adverse drug reactions (ADRs). METHODS: We conducted a case/non-case pharmacovigilance study using data from the AMSP project (German: "Arzneimittelsicherheit in der Psychiatrie"; i.e., Drug Safety in Psychiatry), which collects data on ADRs from patients treated in psychiatric hospitals in Germany, Austria, and Switzerland. We performed a disproportionality analysis of reports of weight gain (> 10% of baseline body weight) calculating reporting odds ratio (ROR). We compared aripiprazole, carbamazepine, lithium, olanzapine, quetiapine, risperidone, and valproate to lamotrigine. Additional analyses related to different mood stabilizers as reference medication were performed. We also assessed sex and age distributions of weight-gain reports. RESULTS: We identified a total of 527 cases of severe drug-induced weight gain representing 7.4% of all severe ADRs. The ROR for lithium was 2.1 (95%CI 0.9-5.1, p > 0.05), which did not reach statistical significance. Statistically significant disproportionate reporting of weight gain was reported for olanzapine (ROR: 11.5, 95%CI 4.7-28.3, p < 0.001), quetiapine (ROR: 3.4, 95%CI 1.3-8.4, p < 0.01), and valproate (ROR: 2.4, 95%CI 1.1-5.0, p = 0.03) compared to lamotrigine. Severe weight gain was more prevalent in non-elderly (< 65 years) than in elderly patients, with an ROR of 7.6 (p < 0.01) in those treated with lithium, and an ROR of 14.7 (p < 0.01) in those not treated with lithium. CONCLUSIONS: Our findings suggest that lithium is associated with more reports of severe weight gain than lamotrigine, although this difference did not reach statistical significance. However, lithium use led to fewer reports of severe weight gain than some alternative drugs for long-term medication (olanzapine, quetiapine, and valproate), which is consistent with recent studies. Monitoring of weight gain and metabolic parameters remains essential with lithium and its alternatives.

Psychedelics in the treatment of eating disorders: Rationale and potential mechanisms.

Eating disorders are serious illnesses showing high rates of mortality and comorbidity with other mental health problems. Psychedelic-assisted therapy has recently shown potential in the treatment of several common comorbidities of eating disorders, including mood disorders, post-traumatic stress disorder, and substance use disorders. The theorized therapeutic mechanisms of psychedelic-assisted therapy suggest that it could be beneficial in the treatment of eating disorders as well. In this review, we summarize preliminary data on the efficacy of psychedelic-assisted therapy in people with anorexia nervosa, bulimia nervosa, and binge eating disorder, which include studies and case reports of psychedelic-assisted therapy with ketamine, MDMA, psilocybin, and ayahuasca. We then discuss the potential therapeutic mechanisms of psychedelic-assisted therapy in these three eating disorders, including both general therapeutic mechanisms and those which are relatively specific to eating disorders. We find preliminary evidence that psychedelic-assisted therapy may be effective in the treatment of anorexia nervosa and bulimia nervosa, with very little data available on binge eating disorder. Regarding mechanisms, psychedelic-assisted therapy may be able to improve beliefs about body image, normalize reward processing, promote cognitive flexibility, and facilitate trauma processing. Just as importantly, it appears to promote general therapeutic factors relevant to both eating disorders and many of their common comorbidities. Lastly, we discuss potential safety concerns which may be associated with these treatments and present recommendations for future research.

Extrapharmacological Safety Topics in Psychedelic-Assisted Psychotherapy.

This Viewpoint proposes methods for optimizing patient and therapist safety during psychedelic-assisted psychotherapy.

Using simple economic games to assess social orienting and prosocial behavior in adolescents with autism spectrum disorder.

Deficits in socio-emotional reciprocity, in prosocial behavior and in developing social relationships are diagnostic criteria of autism spectrum disorder (ASD), usually assessed by self-report or observation. Simple social experiments developed by behavioral economists allow for quantification of ASD-related social behavior. In this study, we used such experiments to compare social-economic decision-making between ASD adolescents and neurotypical controls. Precisely, we analyzed social orienting and prosocial behavior in 17 adolescents with ASD (Asperger syndrome) and 24 matched neurotypical adolescents. We used a two-condition distribution game (possibility of punishment by fellow player versus no such possibility) and an impunity game to examine social orienting (distribution game) and prosocial behavior (both games). Participants with ASD exhibited less social orienting in the distribution game (p = 0.03, d = -0.61). In addition, there was a trend for ASD participants to behave in a more prosocial way than neurotypical participants in the impunity game (p = 0.08, d = 0.60), which was not the case in the no-punishment condition of the distribution game (p = 0.35, r = 0.17). These results demonstrate the potential of simple economic games to capture reduced social orienting in ASD. The unexpected finding of more prosocial behavior in adolescents with autism spectrum disorder than in neurotypical controls adds to the complexity of previously published results. We recommend meta-analytic efforts to determine average effect sizes across studies and elucidate the conditions for prosocial behavior in ASD to occur.

Can psychedelics enhance group psychotherapy? A discussion on the therapeutic factors.

BACKGROUND: Despite the growth of psychedelic research, psychedelic-assisted group psychotherapy (PAGP) has received little attention in comparison to individual psychedelic-assisted psychotherapy models. METHODS: In this article, we aim to discuss the therapeutic potential of PAGP, as well as outline existing models and the challenges of this approach. Using Irvin Yalom's 11 therapeutic factors of group therapy as a basic framework, we analyse current literature from clinical studies and neurobiological research relative to the topic of PAGP. RESULTS: We argue that combining psychedelic substances and group psychotherapy may prove beneficial for increasing group connectedness and interpersonal learning, potentially enhancing prosocial behaviour with direct opportunities to practice newly acquired knowledge about previously maladaptive behavioural patterns. Challenges regarding this approach include a more rigid therapy structure and potential loss of openness from patients, which may be ameliorated by adequate therapeutic training. CONCLUSION: We hope for this article to support clinical research on PAGP by presenting a therapeutic framework and outlining its mechanisms and challenges.

Dear Doctor Letters regarding citalopram and escitalopram: guidelines vs real-world data.

Dear Doctor Letters (DDLs, Direct Healthcare Professional Communications) from 2011 provided guidance regarding QTc-prolonging effects with risk of torsade de pointes during treatment with citalopram and escitalopram. This study examines the DDLs' effects on prescription behavior. Data from 8842 inpatients treated with citalopram or escitalopram with a primary diagnosis of major depressive disorder (MDD) were derived from a European pharmacovigilance study (Arzneimittelsicherheit in der Psychiatrie, AMSP) from 2001 to 2017. It was examined to what extent new maximum doses were adhered to and newly contraindicated combinations with QTc-prolonging drugs were avoided. In addition, the prescriptions of psychotropic drugs before and after DDLs were compared in all 43,480 inpatients with MDD in the data set. The proportion of patients dosed above the new limit decreased from 8 to 1% in patients ≤ 65 years and from 46 to 23% in patients > 65 years old for citalopram versus 14-5% and 47-31% for escitalopram. Combinations of es-/citalopram with other QTc-prolonging psychotropic drugs reduced only insignificantly (from 35.9 to 30.9%). However, the proportion of patients with doses of quetiapine > 150 mg/day substantially decreased within the combinations of quetiapine and es-/citalopram (from 53 to 35%). After the DDLs, prescription of citalopram decreased and of sertraline increased. The DDLs' recommendations were not entirely adhered to, particularly in the elderly and concerning combination treatments. This might partly be due to therapeutic requirements of the included population. Official warnings should consider clinical needs.

Towards an understanding of psychedelic-induced neuroplasticity.

Classic psychedelics, such as LSD, psilocybin, and the DMT-containing beverage ayahuasca, show some potential to treat depression, anxiety, and addiction. Importantly, clinical improvements can last for months or years after treatment. It has been theorized that these long-term improvements arise because psychedelics rapidly and lastingly stimulate neuroplasticity. The focus of this review is on answering specific questions about the effects of psychedelics on neuroplasticity. Firstly, we review the evidence that psychedelics promote neuroplasticity and examine the cellular and molecular mechanisms behind the effects of different psychedelics on different aspects of neuroplasticity, including dendritogenesis, synaptogenesis, neurogenesis, and expression of plasticity-related genes (e.g., brain-derived neurotrophic factor and immediate early genes). We then examine where in the brain psychedelics promote neuroplasticity, particularly discussing the prefrontal cortex and hippocampus. We also examine what doses are required to produce this effect (e.g., hallucinogenic doses vs. "microdoses"), and how long purported changes in neuroplasticity last. Finally, we discuss the likely consequences of psychedelics' effects on neuroplasticity for both patients and healthy people, and we identify important research questions that would further scientific understanding of psychedelics' effects on neuroplasticity and its potential clinical applications.

Validation of the Collaborative Outcomes study on Health and Functioning during Infection Times (COH-FIT) questionnaire for adults.

BACKGROUND: The Collaborative Outcome study on Health and Functioning during Infection Times (COH-FIT; www.coh-fit.com) is an anonymous and global online survey measuring health and functioning during the COVID-19 pandemic. The aim of this study was to test concurrently the validity of COH-FIT items and the internal validity of the co-primary outcome, a composite psychopathology "P-score". METHODS: The COH-FIT survey has been translated into 30 languages (two blind forward-translations, consensus, one independent English back-translation, final harmonization). To measure mental health, 1-4 items ("COH-FIT items") were extracted from validated questionnaires (e.g. Patient Health Questionnaire 9). COH-FIT items measured anxiety, depressive, post-traumatic, obsessive-compulsive, bipolar and psychotic symptoms, as well as stress, sleep and concentration. COH-FIT Items which correlated r ≥ 0.5 with validated companion questionnaires, were initially retained. A P-score factor structure was then identified from these items using exploratory factor analysis (EFA) and confirmatory factor analyses (CFA) on data split into training and validation sets. Consistency of results across languages, gender and age was assessed. RESULTS: From >150,000 adult responses by May 6th, 2022, a subset of 22,456 completed both COH-FIT items and validated questionnaires. Concurrent validity was consistently demonstrated across different languages for COH-FIT items. CFA confirmed EFA results of five first-order factors (anxiety, depression, post-traumatic, psychotic, psychophysiologic symptoms) and revealed a single second-order factor P-score, with high internal reliability (ω = 0.95). Factor structure was consistent across age and sex. CONCLUSIONS: COH-FIT is a valid instrument to globally measure mental health during infection times. The P-score is a valid measure of multidimensional mental health.

Behavioral Response to Catecholamine Depletion in Individuals With Schizophrenia and Healthy Volunteers.

Background and Hypothesis: Dysfunction of the dopamine system is the leading neurobiological hypothesis of schizophrenia. In this study, we tested this hypothesis in the context of aberrance salience theory of delusions using catecholamine depletion. We hypothesized that acute dopamine depletion improves both positive symptoms and salience attribution in individuals with schizophrenia. Study Design: Catecholamine depletion was achieved by oral administration of alpha-methyl-para-tyrosine (AMPT) in 15 individuals with schizophrenia and 15 healthy volunteers. The study design consisted of a randomized, double-blind, placebo-controlled crossover, single-site experimental trial. The main outcome measures were the Scale for the Assessment of Positive Symptoms and the Salience Attribution Test. Study Results: Catecholamine depletion transiently reduced specific psychotic symptoms in symptomatic individuals with schizophrenia, namely delusions and positive formal thought disorder (interaction treatment-by-timepoint, P = .013 and P = .010, respectively). We also found trends for catecholamine depletion to increase relevant bias and adaptive salience in participants with schizophrenia while decreasing them in healthy controls (interaction group-by-treatment, P = .060 and P = .089, respectively). Exploratory analyses revealed that in participants with schizophrenia, higher relevant bias at 3 hours after the end of AMPT treatment corresponded to lower delusional symptoms (Spearman's rho = -0.761, P = .001). Conclusions: This study suggests that the relationship between dopamine hyperactivity and delusional symptoms in schizophrenia is mediated by impaired attribution of salience to reward-predicting stimuli.