Transient drop in the neutrophil count during COVID-19 regardless of clozapine treatment in patients with mental illness / Disminución transitoria del recuento de neutrófilos durante COVID-19 independiente del tratamiento con clozapina en pacientes con esquizofrenia

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Overview of the European post-authorisation study register post-authorization studies performed in Europe from September 2010 to December 2018.

BACKGROUND: The European post-authorisation study (EU PAS) register is a repository launched in 2010 by the European Medicines Agency (EMA). All EMA-requested PAS, commonly observational studies, must be recorded in this register. Multi-database studies (MDS) leveraging secondary data have become an important strategy to conduct PAS in recent years, as reflected by the type of studies registered in the EU PAS register. OBJECTIVES: To analyse and describe PAS in the EU PAS register, with focus on MDS. METHODS: Studies in the EU PAS register from inception to 31st December 2018 were described concerning transparency, regulatory obligations, scope, study type (e.g., observational study, clinical trial, survey, systematic review/meta-analysis), study design, type of data collection and target population. MDS were defined as studies conducted through secondary use of >1 data source not linked at patient-level. Data extraction was carried out independently by 14 centres with expertise in pharmacoepidemiology, using publicly available information in the EU PAS register including study protocol, whenever available, using a standardised data collection form. For validation purposes, a second revision of key fields for a 15% random sample of studies was carried out by a different centre. The inter-rater reliability (IRR) was then calculated. Finally, to identify predictors of primary data collection-based studies/versus those based on secondary use of healthcare databases) or MDS (vs. non-MDS), odds ratios (OR) and 95% confidence intervals (CI) were calculated fitting univariate logistic regression models. RESULTS: Overall, 1426 studies were identified. Clinical trials (N = 30; 2%), systematic reviews/meta-analyses (N = 16; 1%) and miscellaneous study designs (N = 46; 3%) were much less common than observational studies (N = 1227; 86%). The protocol was available for 63% (N = 360) of 572 observational studies requested by a competent authority. Overall, 36% (N = 446) of observational studies were based fully or partially on primary data collection. Of 757 observational studies based on secondary use of data alone, 282 (37%) were MDS. Drug utilisation was significantly more common as a study scope in MDS compared to non-MDS studies. The overall percentage agreement among collaborating centres that collected the data concerning study variables was highest for study type (93.5%) and lowest for type of secondary data (67.8%). CONCLUSIONS: Observational studies were the most common type of studies in the EU PAS register, but 30% used primary data, which is more resource-intensive. Almost half of observational studies using secondary data were MDS. Data recording in the EU PAS register may be improved further, including more widespread availability of study protocols to improve transparency.

Serum lipid trajectories in the years before a lymphoma diagnosis.

We conducted a case-control study of patients from the Clinical Practice Research Datalink in the United Kingdom to describe the trajectories of serum lipid in the years before a diagnosis of lymphoma. Study participants had at least one cholesterol measurement. Multilevel, multivariable linear longitudinal models were fit to examine the adjusted trajectories of serum lipid levels in the years before lymphoma diagnosis. Overall, 11,969 cases of non-Hodgkin lymphoma, 473 of Hodgkin lymphoma, and 61,894 controls were selected. Mean cholesterol levels in the years before the index date showed a more pronounced decrease in the 4 years before lymphoma diagnosis than in controls. Triglycerides levels were unrelated to case status. This research is the first to replicate the results of a similar study conducted in the United States while adjusting for more potential confounders. The newly described different behavior of cholesterol and triglycerides suggests a potential role of cholesterol in lymphomagenesis.

Validity of hospital ICD-10-GM codes to identify anaphylaxis.

PURPOSE: Anaphylaxis (ANA) is an important adverse drug reaction. We examined positive predictive values (PPV) and other test characteristics of ICD-10-GM code algorithms for detecting ANA as used in a multinational safety study (PASS). METHODS: We performed a cross-sectional study on routine data from a German academic hospital (2004-2019, age ≥ 18). Chart review was used for case verification. Potential cases were identified from the hospital administration system. The main outcome required at least one of the following: any type of specific in-hospital code (T78.2, T88.6, and T80.5) OR specific outpatient code in combination with a symptom code OR in-hospital non-specific code (T78.4, T88.7, and Y57.9) in combination with two symptom codes. PPV were calculated with 95% confidence interval. Sensitivity analyses modified type of codes, unit of analysis, verification criteria and time period. The most specific algorithm used only primary codes for ANA (numbers added in brackets). RESULTS: Four hundred and sixteen eligible cases were evaluated, and 78 (37) potential ANA cases were identified. PPV were 62.8% (95% CI 51.1-73.5) (main) and 77.4% (58.9-90.4) (most specific). PPV from all modifications ranged from 12.9% to 80.6%. The sensitivity of the main algorithm was 66.2%, specificity 91.5%, and negative predictive value 92.6%. Corresponding figures for the most specific algorithm were 32.4%, 98.0%, and 87.0%. CONCLUSIONS: The PPV of the main algorithm seems of acceptable validity for use in comparative safety research but will underestimate absolute risks by about a third. Restriction to primary discharge codes markedly improves PPV to the expense of reducing sensitivity.

Use of intravenous iron and risk of anaphylaxis: A multinational observational post-authorisation safety study in Europe.

PURPOSE: This post-authorisation safety study estimated the risk of anaphylaxis in patients receiving intravenous (IV) iron in Europe, with interest in iron dextran and iron non-dextrans. Studies conducted in the United States have reported risk of anaphylaxis to IV iron ranging from 2.0 to 6.8 per 10 000 first treatments. METHODS: Cohort study of IV iron new users, captured mostly through pharmacy ambulatory dispensing, from populations covered by health and administrative data sources in five European countries from 1999 to 2017. Anaphylaxis events were identified through an algorithm that used parenteral penicillin as a positive control. RESULTS: A total of 304 210 patients with a first IV iron treatment (6367 iron dextran), among whom 13-16 anaphylaxis cases were identified and reported as a range to comply with data protection regulations. The pooled unadjusted incidence proportion (IP) ranged from 0.4 (95% confidence interval [CI], 0.2-0.9) to 0.5 (95% CI, 0.3-1.0) per 10 000 first treatments. No events were identified at first dextran treatments. There were 231 294 first penicillin treatments with 30 potential cases of anaphylaxis (IP = 1.2; 95% CI, 0.8-1.7 per 10 000 treatments). CONCLUSION: We found an IP of anaphylaxis from 0.4 to 0.5 per 10 000 first IV iron treatments. The study captured only a fraction of IV iron treatments administered in hospitals, where most first treatments are likely to happen. Due to this limitation, the study could not exclude a differential risk of anaphylaxis between iron dextran and iron non-dextrans. The IP of anaphylaxis in users of penicillin was consistent with incidences reported in the literature.

Identification and Validation of Major Cardiovascular Events in the United Kingdom Data Sources Included in a Multi-database Post-authorization Safety Study of Prucalopride.

INTRODUCTION: A multinational post-authorization safety study assessed cardiovascular safety in initiators of prucalopride for chronic constipation compared with a matched cohort of polyethylene glycol 3350 initiators. The primary safety outcome was major adverse cardiovascular events (MACE), a composite of hospitalization for acute myocardial infarction, stroke, or in-hospital cardiovascular death. We report the validation process for MACE endpoints in United Kingdom (UK) data sources: Clinical Practice Research Datalink (CPRD GOLD), The Health Improvement Network (THIN), and the Information Services Division (ISD) Scotland. METHODS: Modified electronic algorithms from prior research identified potential MACE cases. Validation followed a common protocol, adapted for each database, with all information anonymized: (1) direct confirmation via linkage to hospital records (CPRD GOLD); (2) requests for additional clinical information through questionnaires (CPRD GOLD), free-text (THIN), or abstraction of hospital records (ISD); (3) manual review of electronic records of potential events retrieved by the algorithm (CPRD GOLD/THIN); and (4) event adjudication by three clinicians, blinded to exposure, for all remaining events. RESULTS: Electronic algorithms identified 260 potential MACE cases: 38 confirmed via linkage to hospital records (CPRD GOLD), 56 ruled out as non-cardiovascular death cases (THIN), and three unavailable for review (ISD), leaving 163 potential cases. After manual review with additional information (steps 2 and 3), 45 were considered noncases (CPRD GOLD/THIN). Upon final adjudication (step 4), remaining potential events were adjudicated as definite (n = 62), probable (n = 10), possible (n = 13), or noncases (n = 33). CONCLUSIONS: Given the limitations of relying solely on computer algorithms to identify cardiovascular outcomes, validation with clinical review is essential to guide interpretation.

Cardiovascular Safety of Prucalopride in Patients with Chronic Constipation: A Multinational Population-Based Cohort Study.

INTRODUCTION: The serotonin 5-HT4 receptor agonist prucalopride is approved in the European Union for the treatment of chronic constipation. This offered the unique opportunity to include real-world observational data on cardiovascular safety in the new drug application for approval of prucalopride in the USA. METHODS: This observational population-based cohort study (EUPAS9200) conducted in five data sources (three in the UK, one in Sweden, and one in Germany [which was subsequently excluded from the pooled analyses]) aimed to estimate the pooled adjusted incidence rate ratio for major adverse cardiovascular events (defined as hospitalization for non-fatal acute myocardial infarction or stroke, and in-hospital cardiovascular death) in adult initiators of prucalopride compared with initiators of polyethylene glycol 3350 (PEG) following a common protocol. Standardized incidence rates and incidence rate ratios of major adverse cardiovascular events were derived using propensity score stratification. Sensitivity analyses explored the impact of exposure definition, outcome categories, interim cancer, and unmeasured confounding. RESULTS: The pooled analyses included 5715 initiators of prucalopride and 29,372 initiators of PEG. Average duration of use was 175 days for prucalopride and 82 days for PEG. The pooled standardized incidence rate per 1000 person-years (95% confidence interval) of major adverse cardiovascular events was 6.57 (3.90-10.39) for patients initiating prucalopride and 10.24 (6.97-14.13) for PEG. The pooled adjusted incidence rate ratio for major adverse cardiovascular events was 0.64 (95% confidence interval 0.36-1.14). Results remained consistent in various sensitivity analyses. CONCLUSIONS: The pooled incidence rate ratio estimate was consistent with no indication of an increased risk above the pre-specified safety threshold of 3.00 for major adverse cardiovascular events in patients with chronic constipation using prucalopride as compared with PEG.

Study Design and Cohort Comparability in a Study of Major Cardiovascular Events in New Users of Prucalopride Versus Polyethylene Glycol 3350.

INTRODUCTION: Given prior safety experience with other 5-HT4 agonists for chronic constipation, an observational, population-based cohort study in five data sources from Germany, Sweden, and the UK was conducted to evaluate the cardiovascular safety of prucalopride. OBJECTIVES: Our objective is to describe the methods and resulting comparability of cohorts in a multi-database, multinational study of prucalopride initiators and polyethylene glycol 3350 (PEG) initiators following a harmonized protocol. METHODS: Prucalopride initiators were matched on age, sex, and index date to PEG initiators (1:5 ratio). Study exposures, cardiovascular risk factors, and other covariates were identified from healthcare utilization codes harmonized across databases. Cardiovascular outcomes were identified using database-specific algorithms based on diagnosis codes. The propensity score (PS) in each database was estimated using logistic regression, with prucalopride versus PEG as the outcome and including clinically relevant variables associated with major adverse cardiovascular events. RESULTS: In total, 12,030 prucalopride initiators and 59,985 PEG initiators were identified. After matching and trimming, cohorts from the UK and Sweden were well-balanced for cardiovascular risk factors and cancer. However, in Germany, PEG initiators remained older and sicker than prucalopride initiators. The prevalence of these characteristics also differed from those in the UK and Sweden. The pooled analyses included only data from the UK and Sweden. CONCLUSIONS: Matching, trimming, and PS stratification yielded comparable cohorts in four of five data sources. Use of these methods could not achieve balance for key covariates within the German cohort, likely due to reimbursement differences in Germany.

Estigma: la relevancia del contacto social en el trastorno mental / Stigma: The relevance of social contact in mental disorder

Introducción: El estigma asociado a la enfermedad mental es un problema de salud, discriminando y limitando las oportunidades de las personas que lo padecen. El contacto social con personas que sufren un trastorno mental es una estrategia utilizada para producir cambios en los estereotipos en la población. El objetivo del estudio fue examinar las diferencias en el nivel de estigma en muestras con contacto social y población general. Método: El estudio incluye dos experiencias. La primera (n=42) incluye jugadores de una liga de fútbol abierta en la que juega un equipo de jugadores con diagnóstico de esquizofrenia. En la segunda se compara una muestra sin contacto conocido (n=62) y una muestra con contacto (n=100). La herramienta utilizada de evaluación fue el AQ-27, en versión española (AQ-27-E). Se analizaron la diferencia de medias entre las dos muestras, de cada una de las 9 subescalas. Resultados: En la primera experiencia, todas las subescalas presentaron menor puntuación en poscontacto que en precontacto, excepto responsabilidad, dos subescalas que mostraron diferencias significativas fueron coacción (t=6,057, p= 0,000) y piedad (t=3,661, p= 0,001). En la segunda experiencia, siete subescalas mostraron nivel de significación (p=< 0,05). Responsabilidad y segregación no lo mostraron. Conclusiones: Se observa que el contacto social realizado en entornos cotidianos puede producir un impacto positivo en la reducción del estigma, esto puede contribuir a favorecer la igualdad de oportunidades (AU)

Introduction: The stigma associated with mental illness is a health problem, discriminating and limiting the opportunities for sufferers. Social contact with people suffering a mental disorder is a strategy used to produce changes in population stereotypes. The aim of the study was to examine differences in the level of stigma in samples with social contact and the general population. Method: The study included two experiments. The first (n=42) included players in an open football league who played in a team with players with schizophrenia. In the second included, a sample without known contact (n=62) and a sample with contact (n=100) were compared. The evaluation tool used was AQ-27, Spanish version (AQ-27-E). The mean difference between the two samples of each of the 9 subscales was analyzed. Results: In the first experiment, all the subscales had lower scores in post-contact than in pre-contact, except for responsibility. The two subscales that showed significant differences were duress (t=6.057, p=.000) and Pity (t=3.661, p=.001). In the second experiment, seven subscales showed a significance level (p=<.05). Segregation and responsibility and did not. Conclusions: It is observed that the social contact made in daily situations can have a positive impact on the reduction of stigma. This can help to promote equality of opportunity (AU)

Serum cholesterol trajectories in the 10 years prior to lymphoma diagnosis.

PURPOSE: Many studies suggest a role for cholesterol in cancer development. Serum cholesterol levels have been observed to be low in newly diagnosed lymphoma cases. The objective of these analyses was to examine the time-varying relationship of cholesterol with lymphomagenesis in the 10 years prior to diagnosis by lymphoma subtype. METHODS: Participants were selected from the combined membership of six National Cancer Institute-funded Cancer Research Network health plans from 1998 to 2008, excluding members with human immunodeficiency virus, cancer (except lymphoma), or organ transplants. Incident lymphoma cases within this population were ascertained and matched with up to five controls. Total serum cholesterol, high-density lipoprotein, and low-density lipoprotein were collected from plan databases. Multilevel, multivariable longitudinal models were fit after choosing the best polynomial order by deviance statistics for selected lymphoma histotypes to examine pre-diagnosis cholesterol trajectories: Hodgkin lymphoma (n = 519) and all non-Hodgkin lymphomas combined (n = 12,635) as well as six subtypes of the latter. RESULTS: For all categories, lymphoma cases had statistically significantly lower estimated total serum cholesterol, high-density lipoprotein, and low-density lipoprotein levels than controls in the years prior to diagnosis/index date. Between-group differences were most pronounced 3-4 years prior to diagnosis, when cases' cholesterol levels declined steeply. CONCLUSIONS: This analysis is the first to examine changes in serum cholesterol for a decade prior to lymphoma diagnosis. A drop in cholesterol levels was evident several years before diagnosis. Our results suggest that cholesterol-related pathways have an important relationship with lymphomagenesis and low cholesterol could be a preclinical lymphoma marker.

Stigma: The relevance of social contact in mental disorder. / Estigma: la relevancia del contacto social en el trastorno mental.

INTRODUCTION: The stigma associated with mental illness is a health problem, discriminating and limiting the opportunities for sufferers. Social contact with people suffering a mental disorder is a strategy used to produce changes in population stereotypes. The aim of the study was to examine differences in the level of stigma in samples with social contact and the general population. METHOD: The study included two experiments. The first (n=42) included players in an open football league who played in a team with players with schizophrenia. In the second included, a sample without known contact (n=62) and a sample with contact (n=100) were compared. The evaluation tool used was AQ-27, Spanish version (AQ-27-E). The mean difference between the two samples of each of the 9 subscales was analyzed. RESULTS: In the first experiment, all the subscales had lower scores in post-contact than in pre-contact, except for responsibility. The two subscales that showed significant differences were duress (t=6.057, p=.000) and Pity (t=3.661, p=.001). In the second experiment, seven subscales showed a significance level (p=<.05). Segregation and responsibility and did not. CONCLUSIONS: It is observed that the social contact made in daily situations can have a positive impact on the reduction of stigma. This can help to promote equality of opportunity.

Validation of Cancer Cases Using Primary Care, Cancer Registry, and Hospitalization Data in the United Kingdom.

BACKGROUND: In the United Kingdom, hospital or cancer registry data can be linked to electronic medical records for a subset of general practices and years. METHODS: We used Clinical Practice Research Datalink data (2004-2012) from patients treated for overactive bladder. We electronically identified provisional cases of 10 common cancers in General Practitioner Online Database data and validated them by medical profile review. In practices with linkage to Hospital Episodes Statistics and National Cancer Data Repository (2004-2010), we validated provisional cancer cases against these data sources. This linkage also let us identify additional cancer diagnoses in individuals without cancer diagnosis records in the General Practitioner Online Database. RESULTS: Among 50,840 patients, 1,486 provisional cancer cases were identified in the General Practitioner Online Database for 2004-2012. Medical profile review confirmed 93% of 661 cases in nonlinked practices (range, 100% of non-Hodgkin lymphomas and uterine cancer to 77% of skin melanomas) and 96% of 825 cases in linked practices (100% of kidney and uterine cancers to 92% of melanomas). In the subset of linked practices, for 2004-2010, 720 cases were confirmed, of which 68% were identifiable in the General Practitioner Online Database (range, 90% of breast to 36% of kidney cancers). CONCLUSIONS: Most cases of cancer identified electronically in the General Practitioner Online Database were confirmed. A substantial proportion of cases, especially of cancer types not typically managed by general practitioners, would be missed without Hospital Episodes Statistics and National Cancer Data Repository data (and are likely missed in nonlinked practices). See video abstract at, http://links.lww.com/EDE/B315. REGISTRATION (BEFORE STUDY CONDUCT): European Union electronic Register of Post-Authorisation Studies (EU PAS Registry) number EUPAS5529, http://www.encepp.eu/encepp/viewResource.htm?id=11107.

Cancer Incidence after Initiation of Antimuscarinic Medications for Overactive Bladder in the United Kingdom: Evidence for Protopathic Bias.

STUDY OBJECTIVE: To estimate the incidence of 10 common cancers among patients treated with antimuscarinic medications for overactive bladder (AMOABs). DESIGN: Retrospective cohort study. DATA SOURCE: United Kingdom's Clinical Practice Research Datalink. PATIENTS: A total of 119,912 adults with no previous cancer diagnosis who were new users of AMOABs-darifenacin, fesoterodine, oxybutynin, solifenacin, tolterodine, or trospium-between January 2004 and December 2012. MEASUREMENTS AND MAIN RESULTS: Sex-specific incidence rates per 1000 person-years and 95% confidence intervals (CIs) were estimated for each study cancer (bladder, breast, colorectal, lung, melanoma, non-Hodgkin lymphoma, pancreatic, prostate, renal, and uterine cancer) overall and stratified by time since cohort entry and by cumulative AMOAB dose. Among the 119,912 patients followed for 399,365 person-years, 4117 incident study cancers occurred. The incidence rate of prostate cancer was 14.2 (95% CI 12.9-15.5) in the year after cohort entry and decreased markedly thereafter. The incidence rate of bladder cancer was also higher in the year after cohort entry than subsequently (men: 5.5, 95% CI 4.8-6.4; women: 1.2, 95% CI 1.0-1.5). The incidence rates of both prostate and bladder cancer decreased with increasing cumulative dose of AMOAB. We observed no similar relations between incidence rates of other study cancers and time since cohort entry. CONCLUSION: High incidence rates of bladder and prostate cancer soon after AMOAB initiation and a negative correlation between incidence and cumulative AMOAB dose suggest that protopathic bias is a more likely explanation for these findings than causality. (Protopathic bias in this context means patients' urinary symptoms prompted treatment with an AMOAB, but the symptoms were actually due to a cancer that was already present, although not yet diagnosed or not yet recorded.) To avoid unnecessary delays in the diagnosis of prostate and bladder cancer, physicians should consider these diseases in patients for whom treatment with AMOABs is indicated.

Statin use and risk of multiple myeloma: An analysis from the cancer research network.

Animal and human data suggest statins may be protective against developing multiple myeloma; however, findings may be biased by the interrelationship with lipid levels. We investigated the association between statin use and risk of multiple myeloma in a large US population, with an emphasis on accounting for this potential bias. We conducted a case-control study nested within 6 US integrated healthcare systems participating in the National Cancer Institute-funded Cancer Research Network. Adults aged ≥40 years who were diagnosed with multiple myeloma from 1998-2008 were identified through cancer registries (N = 2,532). For each case, five controls were matched on age, sex, health plan, and membership duration prior to diagnosis/index date. Statin prescriptions were ascertained from electronic pharmacy records. To address potential biases related to lipid levels and medication prescribing practices, multivariable marginal structural models were used to model statin use (≥6 cumulative months) and risk of multiple myeloma, with examination of multiple latency periods. Statin use 48-72 months prior to diagnosis/index date was associated with a suggestive 20-28% reduced risk of developing multiple myeloma, compared to non-users. Recent initiation of statins was not associated with myeloma risk (risk ratio range 0.90-0.99 with 0-36 months latency). Older patients had more consistent protective associations across all latency periods (risk ratio range 0.67-0.87). Our results suggest that the association between statin use and multiple myeloma risk may vary by exposure window and age. Future research is warranted to investigate the timing of statin use in relation to myeloma diagnosis.

Acetaminophen use in pregnancy and neurodevelopment: attention function and autism spectrum symptoms.

Background: Acetaminophen is extensively used during pregnancy. But there is a lack of population-representative cohort studies evaluating its effects on a range of neuropsychological and behavioural endpoints. We aimed to assess whether prenatal exposure to acetaminophen is adversely associated with neurodevelopmental outcomes at 1 and 5 years of age. Methods: This Spanish birth cohort study included 2644 mother-child pairs recruited during pregnancy. The proportion of liveborn participants evaluated at 1 and 5 years was 88.8% and 79.9%, respectively. Use of acetaminophen was evaluated prospectively in two structured interviews. Ever/never use and frequency of use (never, sporadic, persistent) were measured. Main neurodevelopment outcomes were assessed using Childhood Autism Spectrum Test (CAST), Conner's Kiddie Continuous Performance Test (K-CPT) and ADHD-DSM-IV form list. Regression models were adjusted for social determinants and co-morbidities. Results: Over 40% of mothers reported using acetaminophen. Ever-exposed offspring had higher risks of presenting more hyperactivity/impulsivity symptoms [incidence rate ratio (IRR) = 1.41, 95% confidence interval (CI) 1.01-1.98), K-CPT commission errors (IRR = 1.10, 1.03-1.17), and lower detectability scores (coefficient ß = -0.75, -0.13--0.02). CAST scores were increased in ever-exposed males (ß = 0.63, 0.09-1.18). Increased effect sizes of risks by frequency of use were observed for hyperactivity/impulsivity symptoms (IRR = 2.01, 0.95-4.24) in all children, K-CPT commission errors (IRR = 1.32, 1.05-1.66) and detectability (ß = -0.18, -0.36-0.00) in females, and CAST scores in males (ß = 1.91, 0.44-3.38). Conclusions: Prenatal acetaminophen exposure was associated with a greater number of autism spectrum symptoms in males and showed adverse effects on attention-related outcomes for both genders. These associations seem to be dependent on the frequency of exposure.

Animal Assisted Therapy (AAT) Program As a Useful Adjunct to Conventional Psychosocial Rehabilitation for Patients with Schizophrenia: Results of a Small-scale Randomized Controlled Trial.

Currently, one of the main objectives of human-animal interaction research is to demonstrate the benefits of animal assisted therapy (AAT) for specific profiles of patients or participants. The aim of this study is to assess the effect of an AAT program as an adjunct to a conventional 6-month psychosocial rehabilitation program for people with schizophrenia. Our hypothesis is that the inclusion of AAT into psychosocial rehabilitation would contribute positively to the impact of the overall program on symptomology and quality of life, and that AAT would be a positive experience for patients. To test these hypotheses, we compared pre-program with post-program scores for the Positive and Negative Syndrome Scale (PANSS) and the EuroQoL-5 dimensions questionnaire (EuroQol-5D), pre-session with post-session salivary cortisol and alpha-amylase for the last four AAT sessions, and adherence rates between different elements of the program. We conducted a randomized, controlled study in a psychiatric care center in Spain. Twenty-two institutionalized patients with chronic schizophrenia completed the 6-month rehabilitation program, which included individual psychotherapy, group therapy, a functional program (intended to improve daily functioning), a community program (intended to facilitate community reintegration) and a family program. Each member of the control group (n = 8) participated in one activity from a range of therapeutic activities that were part of the functional program. In place of this functional program activity, the AAT-treatment group (n = 14) participated in twice-weekly 1-h sessions of AAT. All participants received the same weekly total number of hours of rehabilitation. At the end of the program, both groups (control and AAT-treatment) showed significant improvements in positive and overall symptomatology, as measured with PANSS, but only the AAT-treatment group showed a significant improvement in negative symptomatology. Adherence to the AAT-treatment was significantly higher than overall adherence to the control group's functional rehabilitation activities. Cortisol level was significantly reduced after participating in an AAT session, which could indicate that interaction with the therapy dogs reduced stress. In conclusion, the results of this small-scale RCT suggest that AAT could be considered a useful adjunct to conventional psychosocial rehabilitation for people with schizophrenia.