Mental health service use in children at risk of significant harm: A record linkage study of a child protection register.

Children with experience of maltreatment, abuse or neglect have higher prevalence of poor mental health. In the United Kingdom, child protection services identify children at risk of significant harm on the Child Protection Register (CPR) and intervene to reduce risk. Prevalence and incidence of mental health service use among this population of children are not well understood. We analysed records from one Scottish Local Authority's CPR, linked to electronic health records for all children in the broader health board region aged 0-17 years. We described mental health service use among children with a CPR registration using measures of mental health prescribing and referrals to child and adolescent mental health services (CAMHS). We calculated age- and sex-specific incidence rates for comparison with the general population. Between 2012 and 2022, we found 1498 children with a CPR registration, with 69% successfully linked to their health records. 20% were registered before birth and median age at registration was 3 years. Incidence rates in all measures of mental health service use were higher in children with a CPR record across all ages (at outcome) and genders compared to the general population. The largest absolute difference was for boys aged 5-9 with a CPR record, who had 31.8 additional mental health prescriptions per 1000 person-years compared to the general population (50.4 vs. 18.6 prescriptions per 1000 person-years, IRR: 2.7). Girls aged 0-4 years with a CPR registration had the largest relative difference, with a rate of CAMHS referral 5.4 times higher than the general population (12.3 vs. 2.3 per 1000 person-years). Our reproducible record linkage of the CPR to health records reveals an increased risk of mental health service use during childhood. Our findings have relevance to public mental health surveillance, service prioritisation and wider policy aiming to reduce childhood exposure to risk of harm.

A recycling quality improvement project to engage the multidisciplinary team with sustainability efforts.

BACKGROUND: The provision of healthcare itself contributes to the global health crisis of the climate emergency. As critical care is a carbon hotspot within hospital medicine, healthcare professionals must take collaborative action to mitigate the environmental impact of the sector. AIMS: The purpose of the project was to engage the critical care multidisciplinary team with sustainability efforts, through involvement in a recycling Quality Improvement Project (QIP). The central QIP aimed to increase the recycling rates of single-use plastic enteral feed bottles in the intensive care unit (ICU) over a 31-day period. STUDY DESIGN: A recycling 'challenge month' was launched, and staff opinion was surveyed before and after this intervention. RESULTS: The QIP demonstrated an increase in feed bottle recycling by 53.2%, representing a carbon-saving effect of up to 6.02 kg CO2e for the intervention month. Following the central QIP, all survey respondents felt encouraged to consider their ICU's environmental impact. CONCLUSIONS: Simple successful QIPs can act as a springboard to engage the staff body with sustainability initiatives and ignite wider conversation and consideration of the climate emergency in daily practice. RELEVANCE FOR CLINICAL PRACTICE: Effective recycling constitutes only one element of responsible environmental stewardship, but authors discuss that it is an effective focus for QIPs. To maximize impact and success within critical care, nursing involvement in leading and participation is essential.

Impulse Oscillometry Versus Spirometry to Detect Bronchiolitis Obliterans Syndrome in Bilateral Lung Transplant Recipients: A Prospective Diagnostic Study.

BACKGROUND: Chronic lung allograft dysfunction (CLAD), and especially bronchiolitis obliterans syndrome (BOS), remain dominant causes of morbidity and mortality after lung transplantation. Interest is growing in the forced oscillation technique, of which impulse oscillometry (IOS) is a form, as a tool to improve our understanding of these disorders. However, data remain limited and no longitudinal studies have been published, meaning there is no information regarding any capacity IOS may have for the early detection of CLAD. METHODS: We conducted a prospective longitudinal study enrolling a consecutive sample of adult bilateral lung transplant recipients with healthy lung allografts or CLAD and performed ongoing paired IOS and spirometry tests on a clinically determined basis. We assessed for correlations between IOS and spirometry and examined any predictive value either modality may hold for the early detection of BOS. RESULTS: We enrolled 91 patients and conducted testing for 43 mo, collecting 558 analyzable paired IOS and spirometry tests, with a median of 9 tests per subject (interquartile range, 5-12) and a median testing interval of 92 d (interquartile range, 62-161). Statistically significant moderate-to-strong correlations were demonstrated between all IOS parameters and spirometry, except resistance at 20 Hz, which is a proximal airway measure. No predictive value for the early detection of BOS was found for IOS or spirometry. CONCLUSIONS: This study presents the first longitudinal data from IOS after lung transplantation and adds considerably to the growing literature, showing unequivocal correlations with spirometry but failing to demonstrate a predictive value for BOS.

Association of Clostridioides difficile infection rates with social determinants of health in Denver area census tracts, 2016-2019.

We evaluated the association between census tract measures of socioeconomic status and Clostridioides difficile infection (CDI) rates in the Denver metro area from 2016 to 2019. Social vulnerability index, poverty, and race were associated with CDI. Findings may relate to differences in chronic disease prevalence, antibiotic exposure, and access to quality care.

Implementing a Bundle to Improve Surgical Site Infection Rates for Patients Undergoing Nonvaginal-Approach Hysterectomy at a Midwestern Teaching Hospital.

Accrediting organizations, third-party payers, and patients review the surgical site infection (SSI) rates of health care organizations. Infection preventionists collaborate with perioperative personnel to decrease SSI rates; they also monitor and report SSI information to national organizations. The standard infection ratio is a comparison of the observed number of SSIs to the predicted number of SSIs based on national benchmark data. Leaders of a midwestern teaching hospital convened an interdisciplinary team (eg, surgeons, perioperative leaders, infection preventionists) to address a standard infection ratio after hysterectomies that was greater than 1.0. The team reviewed national guidelines and published articles on decreasing SSIs (including recommendations for vaginal preparation) before developing and implementing a hysterectomy-specific bundle for SSI prevention. The rate of SSIs decreased 68% after the implementation of the bundle. Perioperative personnel at this facility continue to use the bundle and infection preventionists monitor and report compliance with the bundle's elements.

Inequalities in children's mental health care: analysis of routinely collected data on prescribing and referrals to secondary care.

BACKGROUND: One in eight children in the United Kingdom are estimated to have a mental health condition, and many do not receive support or treatment. The COVID-19 pandemic has negatively impacted mental health and disrupted the delivery of care. Prevalence of poor mental health is not evenly distributed across age groups, by sex or socioeconomic groups. Equity in access to mental health care is a policy priority but detailed socio-demographic trends are relatively under-researched. METHODS: We analysed records for all mental health prescriptions and referrals to specialist mental health outpatient care between the years of 2015 and 2021 for children aged 2 to 17 years in a single NHS Scotland health board region. We analysed trends in prescribing, referrals, and acceptance to out-patient treatment over time, and measured differences in treatment and service use rates by age, sex, and area deprivation. RESULTS: We identified 18,732 children with 178,657 mental health prescriptions and 21,874 referrals to specialist outpatient care. Prescriptions increased by 59% over the study period. Boys received double the prescriptions of girls and the rate of prescribing in the most deprived areas was double that in the least deprived. Mean age at first mental health prescription was almost 1 year younger in the most deprived areas than in the least. Referrals increased 9% overall. Initially, boys and girls both had an annual referral rate of 2.7 per 1000, but this fell 6% for boys and rose 25% for girls. Referral rate for the youngest decreased 67% but increased 21% for the oldest. The proportion of rejected referrals increased steeply since 2020 from 17 to 30%. The proportion of accepted referrals that were for girls rose to 62% and the mean age increased 1.5 years. CONCLUSIONS: The large increase in mental health prescribing and changes in referrals to specialist outpatient care aligns with emerging evidence of increasing poor mental health, particularly since the start of the COVID-19 pandemic. The static size of the population accepted for specialist treatment amid greater demand, and the changing demographics of those accepted, indicate clinical prioritisation and unmet need. Persistent inequities in mental health prescribing and referrals require urgent action.

Intensive care nurse practitioners in Australia: A description of a service model in an adult tertiary intensive care unit.

BACKGROUND: Although well-established internationally, nurse practitioners (NPs) in Australian adult intensive care units (ICUs) are rare. Australian literature clearly highlights the importance of creating ICU NP roles to meet emerging demands. An ICU NP model of care at a metropolitan hospital in Sydney provides care in four core practice areas: complex case management, vascular access, tracheostomy management, and intrahospital transport of critically ill patients. The ICU NPs also provide training and assessment for ICU nurses and medical officers in these same core practice areas and can efficiently meet service gaps in crisis such as the most recent COVID-19 pandemic. RESULTS: The ICU NP program described is an innovative model of care that has demonstrated potential benefits to patients and their families. Potential benefits to the healthcare system including supporting advanced practice nursing development in regional and rural Australia and in addressing future ICU workforce issues are also identified. This model of care provides a clear role and structure for the integration of NPs in the adult ICU. Research to evaluate the impact of the role is required and is underway. CONCLUSIONS: This model is being used to develop a national adult ICU NP fellowship training program for ICU transitional NPs preparing for endorsement or endorsed NPs who require additional ICU-specific training. This immersive clinical training program combined with didactic learning modules offers a framework to support the implementation of the adult ICU NP role as well as a framework for NP fellowship programs in other specialties.

Rare case of cystic anterior mediastinal tuberculosis in an immunocompetent patient.

We report a case of a 28-year-old immunocompetent woman found to have a mediastinal lesion on chest x-ray performed as part of a visa renewal process. Computed tomographic imaging revealed a cystic superior anterior mediastinal mass. Although initially asymptomatic, the woman subsequently developed progressive chest discomfort. She underwent surgical resection of the mass. Histological assessment demonstrated necrotizing granulomatous inflammation, while Gene Xpert™ testing was positive for Mycobacterium tuberculosis complex and she was subsequently commenced on anti-tuberculous therapy.

Improving medical research in the United Kingdom.

Poor quality medical research causes serious harms by misleading healthcare professionals and policymakers, decreasing trust in science and medicine, and wasting public funds. Here we outline underlying problems including insufficient transparency, dysfunctional incentives, and reporting biases. We make the following recommendations to address these problems: Journals and funders should ensure authors fulfil their obligation to share detailed study protocols, analytical code, and (as far as possible) research data. Funders and journals should incentivise uptake of registered reports and establish funding pathways which integrate evaluation of funding proposals with initial peer review of registered reports. A mandatory national register of interests for all those who are involved in medical research in the UK should be established, with an expectation that individuals maintain the accuracy of their declarations and regularly update them. Funders and institutions should stop using metrics such as citations and journal's impact factor to assess research and researchers and instead evaluate based on quality, reproducibility, and societal value. Employers and non-academic training programmes for health professionals (clinicians hired for patient care, not to do research) should not select based on number of research publications. Promotions based on publication should be restricted to those hired to do research.

Identifying multimorbidity clusters in an unselected population of hospitalised patients.

Multimorbidity (multiple coexisting chronic health conditions) is common and increasing worldwide, and makes care challenging for both patients and healthcare systems. To ensure care is patient-centred rather than specialty-centred, it is important to know which conditions commonly occur together and identify the corresponding patient profile. To date, no studies have described multimorbidity clusters within an unselected hospital population. Our aim was to identify and characterise multimorbidity clusters, in a large, unselected hospitalised patient population. Linked inpatient hospital episode data were used to identify adults admitted to hospital in Grampian, Scotland in 2014 who had ≥ 2 of 30 chronic conditions diagnosed in the 5 years prior. Cluster analysis (Gower distance and Partitioning around Medoids) was used to identify groups of patients with similar conditions. Clusters of conditions were defined based on clinical review and assessment of prevalence within patient groups and labelled according to the most prevalent condition. Patient profiles for each group were described by age, sex, admission type, deprivation and urban-rural area of residence. 11,389 of 41,545 hospitalised patients (27%) had ≥ 2 conditions. Ten clusters of conditions were identified: hypertension; asthma; alcohol misuse; chronic kidney disease and diabetes; chronic kidney disease; chronic pain; cancer; chronic heart failure; diabetes; hypothyroidism. Age ranged from 51 (alcohol misuse) to 79 (chronic heart failure). Women were a higher proportion in the chronic pain and hypothyroidism clusters. The proportion of patients from the most deprived quintile of the population ranged from 6% (hypertension) to 14% (alcohol misuse). Identifying clusters of conditions in hospital patients is a first step towards identifying opportunities to target patient-centred care towards people with unmet needs, leading to improved outcomes and increased efficiency. Here we have demonstrated the face validity of cluster analysis as an exploratory method for identifying clusters of conditions in hospitalised patients with multimorbidity.

Reforms to improve reproducibility and quality must be coordinated across the research ecosystem: the view from the UKRN Local Network Leads.

Many disciplines are facing a "reproducibility crisis", which has precipitated much discussion about how to improve research integrity, reproducibility, and transparency. A unified effort across all sectors, levels, and stages of the research ecosystem is needed to coordinate goals and reforms that focus on open and transparent research practices. Promoting a more positive incentive culture for all ecosystem members is also paramount. In this commentary, we-the Local Network Leads of the UK Reproducibility Network-outline our response to the UK House of Commons Science and Technology Committee's inquiry on research integrity and reproducibility. We argue that coordinated change is needed to create (1) a positive research culture, (2) a unified stance on improving research quality, (3) common foundations for open and transparent research practice, and (4) the routinisation of this practice. For each of these areas, we outline the roles that individuals, institutions, funders, publishers, and Government can play in shaping the research ecosystem. Working together, these constituent members must also partner with sectoral and coordinating organisations to produce effective and long-lasting reforms that are fit-for-purpose and future-proof. These efforts will strengthen research quality and create research capable of generating far-reaching applications with a sustained impact on society.

Impact of Substance Use Disorder on Quality of Inpatient Mental Health Services for People With Anxiety and Depression.

Objective: Substance use disorders are commonly comorbid with anxiety and depressive disorders and are associated with poor treatment outcomes. The mechanisms underlying this association remain unclear-one possibility is that patients with anxiety/depressive disorders and substance use disorders receive poorer treatment. Concerns have been raised about the quality of inpatient care received by patients with substance use disorders. The purspose of this research was to examine the quality of care received by inpatients with an anxiety or depressive disorder, comparing subgroups with or without a comorbid substance use disorder. Methods: This was a retrospective case-note review of 3,795 patients admitted to inpatient psychiatric wards in England. Data were gathered on all acute admissions with anxiety/depressive illness over a 6-month period, for a number of measures of quality of care derived from national standards. Association of coexisting substance use disorders with a variety of quality of care outcomes (relating to assessment, care planning, medication management, psychological therapies, discharge, crisis planning, and follow-up) was investigated using multivariable regression analyses. Results: In all, 543 (14.3%) patients in the study had a secondary diagnosis of a substance use disorder. Patients with substance use disorders were less likely to have had care plans that were developed jointly (i.e., with input from both patient and clinician; odds ratio [OR] = 0.76, 95% confidence interval [CI] [0.55, 0.93], p = .034) and less likely to have had their medication reviewed either during the admission (OR = 0.83, 95% CI [0.69, 0.94], p = .030) or at follow-up after discharge (OR = 0.58, 95% CI [0.39, 0.86], p = .007). Carers of patients with substance use disorders were less likely to have been provided with information about available support services (OR = 0.79, 95% CI [0.57, 0.98], p = .047). Patients with substance use disorders were less likely to have received adequate (at least 24 hours) notice in advance of their discharge (OR = 0.72, 95% CI [0.54, 0.96], p = .033), as were their carers (OR = 0.63, 95% CI [0.41, 0.85], p = .007). They were less likely to have a crisis plan in place at the point of discharge (OR = 0.85, 95% CI [0.74, 0.98], p = .044). There was also strong evidence that patients with substance use disorders were less likely to have been referred for psychological therapy (OR = 0.69, 95% CI [0.55, 0.87], p = .002). Conclusions: We found evidence of poorer quality of care for inpatients with anxiety and depressive disorders with comorbid substance use disorders, highlighting the need for more to be done to support these patients. Discrepancies in care quality may be contributed to the poor treatment outcomes experienced by patients with substance use disorders, and strategies to reduce this inequality are necessary to improve the well-being of this substantial patient group.

Telemedicine for Family Planning: A Scoping Review.

Telemedicine has the potential to increase access to family planning. The most common application involved the use of text message reminders and mobile apps. Text messaging increased knowledge in a variety of settings, but had no effect on contraceptive uptake and use. Two randomized studies found that text messaging improved continuation of oral contraceptives and injectables. Telemedicine provision of medication abortion included both clinic-to-clinic and direct-to-patient models of care. Telemedicine provision of medication abortion has been found to be equally safe and effective as in-person provision. Some measures of satisfaction are higher with telemedicine. Telemedicine may improve access to early abortion.

The long-term health effects of attending a selective school: a natural experiment.

BACKGROUND: Education is widely associated with better physical and mental health, but isolating its causal effect is difficult because education is linked with many socioeconomic advantages. One way to isolate education's effect is to consider environments where similar students are assigned to different educational experiences based on objective criteria. Here we measure the health effects of assignment to selective schooling based on test score, a widely debated educational policy. METHODS: In 1960s Britain, children were assigned to secondary schools via a test taken at age 11. We used regression discontinuity analysis to measure health differences in 5039 people who were separated into selective and non-selective schools this way. We measured selective schooling's effect on six outcomes: mid-life self-reports of health, mental health, and life limitation due to health, as well as chronic disease burden derived from hospital records in mid-life and later life, and the likelihood of dying prematurely. The analysis plan was accepted as a registered report while we were blind to the health outcome data. RESULTS: Effect estimates for selective schooling were as follows: self-reported health, 0.1 worse on a 4-point scale (95%CI - 0.2 to 0); mental health, 0.2 worse on a 16-point scale (- 0.5 to 0.1); likelihood of life limitation due to health, 5 percentage points higher (- 1 to 10); mid-life chronic disease diagnoses, 3 fewer/100 people (- 9 to + 4); late-life chronic disease diagnoses, 9 more/100 people (- 3 to + 20); and risk of dying before age 60, no difference (- 2 to 3 percentage points). Extensive sensitivity analyses gave estimates consistent with these results. In summary, effects ranged from 0.10-0.15 standard deviations worse for self-reported health, and from 0.02 standard deviations better to 0.07 worse for records-derived health. However, they were too imprecise to allow the conclusion that selective schooling was detrimental. CONCLUSIONS: We found that people who attended selective secondary school had more advantaged economic backgrounds, higher IQs, higher likelihood of getting a university degree, and better health. However, we did not find that selective schooling itself improved health. This lack of a positive influence of selective secondary schooling on health was consistent despite varying a wide range of model assumptions.

Telehealth Interventions to Improve Obstetric and Gynecologic Health Outcomes: A Systematic Review.

OBJECTIVE: To systematically review the effectiveness of telehealth interventions for improving obstetric and gynecologic health outcomes. DATA SOURCES: We conducted a comprehensive search for primary literature in ClinicalTrials.gov, Cochrane Library, Cochrane Collaboration Registry of Controlled Trials, EMBASE, PubMed, and MEDLINE. METHODS OF STUDY SELECTION: Qualifying primary studies had a comparison group, were conducted in countries ranked very high on the United Nations Human Development Index, published in English, and evaluated obstetric and gynecologic health outcomes. Cochrane Collaboration's tool and ROBINS-I tool were used for assessing risk of bias. Summary of evidence tables were created using the United States Preventive Services Task Force Summary of Evidence Table for Evidence Reviews. TABULATION, INTEGRATION, RESULTS: Of the 3,926 published abstracts identified, 47 met criteria for inclusion and included 31,967 participants. Telehealth interventions overall improved obstetric outcomes related to smoking cessation and breastfeeding. Telehealth interventions decreased the need for high-risk obstetric monitoring office visits while maintaining maternal and fetal outcomes. One study found reductions in diagnosed preeclampsia among women with gestational hypertension. Telehealth interventions were effective for continuation of oral and injectable contraception; one text-based study found increased oral contraception rates at 6 months. Telehealth provision of medication abortion services had similar clinical outcomes compared with in-person care and improved access to early abortion. Few studies suggested utility for telehealth to improve notification of sexually transmitted infection test results and app-based intervention to improve urinary incontinence symptoms. CONCLUSION: Telehealth interventions were associated with improvements in obstetric outcomes, perinatal smoking cessation, breastfeeding, early access to medical abortion services, and schedule optimization for high-risk obstetrics. Further well-designed studies are needed to examine these interventions and others to generate evidence that can inform decisions about implementation of newer telehealth technologies into obstetrics and gynecology practice.

Impulse Control Disorders in Dopamine Agonist-Treated Hyperprolactinemia: Prevalence and Risk Factors.

CONTEXT: There are growing reports of dopamine agonist (DA)-induced impulse control disorders (ICDs) in hyperprolactinemic patients. However, the magnitude of this risk and predictive factors remain uncertain. OBJECTIVE: To determine ICD prevalence and risk factors in DA-treated hyperprolactinemic patients compared to community controls. DESIGN, SETTING AND PARTICIPANTS: Multicenter cross-sectional analysis of 113 patients and 99 healthy controls. MAIN OUTCOME MEASURES: Participants completed a neuropsychological questionnaire consisting of the Depression Anxiety Stress Scale (DASS21), Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP-S), Hypersexual Behavior Inventory (HBI), Hypersexual Behavior Consequences Scale and Social Desirability Response Set Scale. Demographic and clinical data were collated to determine ICD risk factors. Patients testing positive for an ICD were offered a semistructured psychological interview. RESULTS: Patients were more likely than controls to test positive by QUIP-S for any ICD (61.1 vs 42.4%, P = .01), hypersexuality (22.1 vs 8.1%, P = .009), compulsive buying (15.9 vs 6.1%, P = .041) and punding (18.6 vs 6.1%, P = 0.012), and by HBI for hypersexuality (8.0 vs 0.0%, P = 0.004). Independent risk factors were male sex (odds ratio [OR] 13.85), eugonadism (OR 7.85), Hardy's tumor score and psychiatric comorbidity (OR 6.86) for hypersexuality, and age (OR 0.95) for compulsive buying. DASS21 subset scores were higher in patients vs controls and in patients with vs without different ICDs. Only 19/51 (37.3%) interviewed patients were aware of the relationship between DAs and ICDs before the study. CONCLUSIONS: DA therapy poses a high, previously underestimated risk of ICDs, especially in the form of hypersexuality in eugonadal men.

Severe Respiratory Syncytial Virus Infection in Hospitalized Children Less Than 3 Years of Age in a Temperate and Tropical Climate.

BACKGROUND: Respiratory syncytial virus (RSV) infection is a frequent cause of hospitalization in infants younger than 3 years of age. We aimed to determine the factors associated with severe RSV disease. METHODS: Retrospective medical review of children up to 3 years of age admitted for laboratory-proven RSV infection between January 1, 2013, and December 31, 2014, was conducted at the Women's and Children's Hospital, Adelaide, South Australia, and the Paediatric Department at Cairns Hospital, Cairns, North Queensland. Severity of infection was determined using the validated Brisbane RSV Infection Severity Score. RESULTS: Four-hundred ninety-six children (383 at Women's and Children's Hospital and 113 at Cairns Hospital) were included in the study, with 76, 323 and 97 patients identified as having mild, moderate or severe disease, respectively. Decreasing age [odds ratio (OR) = 0.95; 95% confidence interval (CI) = 0.90-0.99, P = 0.020), and being Indigenous, increased (OR = 2.6; 95% CI = 1.4-4.9, P = 0.002) the risk of severe RSV infection in hospitalized children. Underlying respiratory (P = 0.029, OR = 2.5; 95% CI = 1.1-5.8) or cardiac (OR = 2.7; 95% CI = 1.1-6.4, P = 0.024) conditions, as well as the presence of tachypnoea on admission (OR = 2.2; 95% CI = 1.2-4.1, P = 0.009), were also independent predictors of severe RSV infection. Seasonal variation in hospitalization was observed between temperate and tropical climates but was not associated with disease severity. CONCLUSIONS: Young infants, Indigenous patients and children with underlying respiratory and cardiac disease should be observed closely for signs of deterioration. Infants with tachypnoea on admission should be continuously monitored.

Hyperlipidemic diet causes loss of olfactory sensory neurons, reduces olfactory discrimination, and disrupts odor-reversal learning.

Currently, 65% of Americans are overweight, which leads to well-supported cardiovascular and cognitive declines. Little, however, is known concerning obesity's impact on sensory systems. Because olfaction is linked with ingestive behavior to guide food choice, its potential dysfunction during obesity could evoke a positive feedback loop to perpetuate poor ingestive behaviors. To determine the effect of chronic energy imbalance and reveal any structural or functional changes associated with obesity, we induced long-term, diet-induced obesity by challenging mice to high-fat diets: (1) in an obesity-prone (C57BL/6J) and obesity-resistant (Kv1.3(-/-)) line of mice, and compared this with (2) late-onset, genetic-induced obesity in MC4R(-/-) mice in which diabetes secondarily precipitates after disruption of the hypothalamic axis. We report marked loss of olfactory sensory neurons and their axonal projections after exposure to a fatty diet, with a concomitant reduction in electro-olfactogram amplitude. Loss of olfactory neurons and associated circuitry is linked to changes in neuronal proliferation and normal apoptotic cycles. Using a computer-controlled, liquid-based olfactometer, mice maintained on fatty diets learn reward-reinforced behaviors more slowly, have deficits in reversal learning demonstrating behavioral inflexibility, and exhibit reduced olfactory discrimination. When obese mice are removed from their high-fat diet to regain normal body weight and fasting glucose, olfactory dysfunctions are retained. We conclude that chronic energy imbalance therefore presents long-lasting structural and functional changes in the operation of the sensory system designed to encode external and internal chemical information and leads to altered olfactory- and reward-driven behaviors.