John Wallert

Karolinska Institutet | KI · Department of Clinical Neuroscience

BACKGROUND: Machine learning algorithms hold potential for improved prediction of all-cause mortality in cardiovascular patients, yet have not previously been developed with high-quality population data. This study compared four popular machine learning algorithms trained on unselected, nation-wide population data from Sweden to solve the binary cl...

Compared to best performances, worst performances on multi-trial psychometric tests often show stronger correlations with other g-loaded cognitive tests, which is known as the Worst Performance Rule (WPR). While worst performances may be more sensitive or specific to cognitive decline, clinical psychometric research and neuropsychological practice...

BACKGROUND: Psychosocial stress might trigger myocardial infarction (MI). Increased MI incidence coincides with recurrent time-periods during the year perceived as particularly stressful in the population. METHODS: A stress-triggering hypothesis on the risk of MI onset was investigated with Swedish population data on MI hospital admission date an...

BACKGROUND Emotional distress (depression and anxiety) has been known to affect mortality after a myocardial infarction (MI). One possible mechanism is through medication non-adherence. Few studies have investigated the link between statin adherence and emotional distress, and results are not consistent. We aimed to explore whether emotional distre...

BACKGROUND: Cognitive ability (CA) is positively related to later health, health literacy, health behaviours and longevity. Accordingly, a lower CA is expected to be associated with poorer adherence to medication. We investigated the long-term role of CA in adherence to prescribed statins in male patients after a first myocardial infarction (MI)....

Background: Cognitive reserve (CR) is hypothesized to partially explain the discrepancy between Alzheimer's disease related brain pathology and cognitive performance. Educational attainment is often used as a proxy for CR. Objective: To examine the association of years of education and the relationship between atrophy in the medial temporal lobe...

Objective: Investigate associations between prepregnancy participation and performance in a demanding cross-country ski race (proxy for exercise volume and fitness) and perinatal outcomes. Preregistered protocol: osf.io/aywg2. Design: Prospective cohort study. Setting: Based on entire overlap between the Vasaloppet registry and the population-...

Background: Fatigue is a common presenting problem in healthcare settings, often attributed to chronic psychosocial stress. Understanding of fatigue and development of evidence-based treatments is hampered by a lack of consensus regarding diagnostic definitions and outcomes to be measured in clinical trials. This study aimed to map outcome domains...

Background Patients with myocardial infarction (MI) have a high prevalence of diabetes mellitus (DM). Prognosis in patients with MI and DM is substantially worse than for those without DM. An unacceptably high proportion of patients with DM remain both undiagnosed and undertreated despite follow-up at cardiac rehabilitation (CR) centres. Purpose U...

Background Symptoms related to chronic stress are prevalent and entail high societal costs, yet there is a lack of international consensus regarding diagnostics and treatment. A new stress-related diagnosis, exhaustion disorder, was introduced into the Swedish version of ICD-10 in 2005. Since then, use of the diagnosis has increased rapidly. Aims...

This study applied supervised machine learning with multi-modal data to predict remission of major depressive disorder (MDD) after psychotherapy. Genotyped adult patients ( n = 894, 65.5% women, age 18–75 years) diagnosed with mild-to-moderate MDD and treated with guided Internet-based Cognitive Behaviour Therapy (ICBT) at the Internet Psychiatry C...

Background: Benefits of cardiac rehabilitation (CR) programme components on attaining risk factor targets post-myocardial infarction (MI) and their predictive strength relative to patient characteristics remain unclear. We aimed to identify organizational and patient-level predictors of risk factor target attainment at one-year post-MI. Methods: In...

In clinical trials of obsessive-compulsive disorder (OCD), clinical outcomes are generally measured using lengthy clinician-administered interviews. However, in routine clinical practice, many clinicians lack the time to administer such instruments. This study evaluated cut-offs for treatment response and remission in OCD using the self-rated Obses...

In summary, we provide the field with empirically derived Y-BOCS severity benchmarks across the lifespan which will be useful in research and clinical settings (subclinical OCD: 0-13 points; mild OCD: 14-21 points; moderate OCD: 22-29 points; severe OCD: 30-40 points). However, due to the modest accuracy of the classifications, we caution against t...

Background β-blockers are routinely administered to patients following myocardial infarction (MI), yet their potential effect on health-related quality of life (HRQoL) is not entirely understood. We investigated the relationship between two different doses of β-blockers with HRQoL following MI. Methods and results This nationwide observational stu...

In clinical trials of obsessive-compulsive disorder (OCD), clinical outcomes are generally measured using lengthy clinician-administered interviews. However, in routine clinical practice, many clinicians lack the time to administer such instruments. This study evaluated cut-offs for treatment response and remission in OCD using the self-rated Obses...

Background: Symptoms related to chronic stress are prevalent and entail high societal costs, yet there is a lack of international consensus regarding diagnostics and treatment. A new stress-related diagnosis, Exhaustion Disorder (ED), was introduced into the Swedish version of ICD-10 in 2005. Since then, use of the diagnosis has increased rapidly....

BACKGROUND: Depression and anxiety are known risk factors for patients with myocardial infarction (MI). However, the association of a previous psychiatric diagnosis of depression or anxiety, or such self-reported symptoms, with cardiovascular outcomes and mortality post MI has not previously been examined in the same nationwide cohort. METHODS: Us...

We compared the odds of smoking cessation at 2-months post-myocardial infarction (MI), before and after implementing routines optimizing use of evidence-based smoking cessation methods, with start during admission. The following routines were implemented at six Swedish hospitals: cardiac rehabilitation nurses offering smokers consultation during ad...

Background The benefits of specific cardiac rehabilitation (CR) programme components on patient outcomes after myocardial infarction (MI) remain unclear, as does their relative predictive strength compared to patient-level predictors. Purpose To identify CR organizational and patient-level predictors for reaching risk factor targets at one-year po...

Background For smokers who suffer a myocardial infarction (MI), smoking cessation is the most effective measure to reduce recurrent event risk. Still, evidence-based treatment methods for aiding smoking cessation post-MI are underused. Purpose To compare the odds of smoking cessation at two-months post-MI before and after implementing a set of pre...

Background: Evidence-based methods for aiding smoking cessation post-myocardial infarction are effective yet underused in clinical practice. We compared the odds of smoking cessation at 2-months post-myocardial infarction before versus after implementing a set of pre-specified routines optimizing evidence-based treatment methods for smoking cessati...

Objective To assess executive functions (EFs) in patients with body dysmorphic disorder (BDD) and obsessive–compulsive disorder (OCD) compared with healthy controls. Methods Adults diagnosed with BDD (n = 26) or OCD (n = 29) according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, and healthy controls (n = 28) underwe...

The cause of cognitive dedifferentiation has been suggested as specific to late-life abnormal cognitive decline rather than a general feature of aging. This hypothesis was tested in two large cohorts with different characteristics. Individuals (n = 2710) were identified in the Alzheimer's Disease Neuroimaging Initiative (ADNI) research database (n...

Background: The U-CARE Heart trial was one of the first randomized controlled trials to evaluate the effect of internet-based cognitive behavioral therapy on self-reported symptoms of anxiety or depression for patients with a recent myocardial infarction. While the effects of internet-based cognitive behavioral therapy on Hospital Anxiety and Depre...

BACKGROUND: Whether a patient benefits from psychotherapy or not is arguably a complex process and heterogeneous information extracted from process, genetic, demographic, and clinical data could contribute to the prediction of remission status after psychotherapy. This study applied supervised machine learning with such multi-modal baseline data to...

Objective To assess executive functions in patients with Body Dysmorphic Disorder (BDD) and Obsessive-Compulsive Disorder (OCD) compared with healthy controls. Methods Adults diagnosed with BDD (n=26) or OCD (n=29) according to DSM-5, and healthy controls (n=28) underwent validated and computerized neuropsychological tests; spatial working memory...

Purpose The study aimed to explore the self-perceived cognitive status and cognitive challenges associated with lifestyle changes in cardiac rehabilitation among elderly myocardial infarction (MI) patients (≥65 years). Further, the study explored coping strategies developed to manage these challenges in the everyday life. Methods Nine patients wer...

BACKGROUND: Cognitive dedifferentiation describes the process in which acquired cognitive skills decline in later life making them more similar. The cause of cognitive dedifferentiation has been suggested as specific to late-life abnormal cognitive decline rather than a general feature of aging. This hypothesis was tested in two large cohorts with...

BACKGROUND: Individuals with early phase cognitive impairment are frequently affected by existential distress, social avoidance and associated health issues (including symptoms of stress, anxiety, and depression). The demand for efficient psychological support is crucial from both an individual and a societal perspective. We have developed a novel...

Background The U-CARE Heart trial was one of the first randomized controlled trials to evaluate the effect of internet-based cognitive behavioral therapy on self-reported symptoms of anxiety or depression for patients with a recent myocardial infarction. While the effects of internet-based cognitive behavioral therapy on Hospital Anxiety and Depres...

BACKGROUND The U-CARE Heart trial was one of the first randomized controlled trials to evaluate the effect of internet-based cognitive behavioral therapy on self-reported symptoms of anxiety or depression for patients with a recent myocardial infarction. While the effects of internet-based cognitive behavioral therapy on Hospital Anxiety and Depres...

AIMS Dose-dependent effects of β-blockers on survival and cardiovascular outcomes after myocardial infarction (MI) are not well understood. We investigated the long-term risk of cardiovascular events in patients with different doses of β-blockers after MI. METHODS AND RESULTS This was a nationwide observational study linking morbidity, mortality,...

This thesis is compiled from four studies dealing with the prediction of myocardial infarction (MI) and some associated risk behaviours post MI. Study 1 extends the field of possible psychosocial stress-triggering of MI to Sweden, and to the phenomenon of temporal crests and troughs in national MI rates. These findings are in the present thesis in...

Background: There remains a lack of large-scale clinical studies of cognitive impairment that aim to increase diagnostic and prognostic accuracy as well as validate previous research findings. The MemClin project will amass large quantities of cross-disciplinary data allowing for the construction of robust models to improve diagnostic accuracy, ex...

BACKGROUND: The Heart School is a standard component of cardiac rehabilitation after myocardial infarction in Sweden. The group-based educational intervention aims to improve modifiable risks, in turn reducing subsequent morbidity and mortality. However, an evaluation with respect to mortality is lacking. AIMS: Using linked population registries,...

Background: Patients with symptoms of depression and/or anxiety - emotional distress - after a myocardial infarction (MI) have been shown to have worse prognosis and increased healthcare costs. However, whether specific subgroups of patients with emotional distress are more vulnerable is less well established. The purpose of this study was to iden...

Graphical depiction of model training, testing, and validation.

BACKGROUND Patients with first-time myocardial infarction (MI) and diabetes mellitus (DM) constitute a vulnerable subgroup of cardiovascular (CV) patients for which secondary prevention is particularly important. We investigated if patients with versus without DM differ in attaining four main lifestyle-related cardiac rehabilitation (CR) targets,...

BACKGROUND: Low adherence to recommended treatments is a multifactorial problem for patients in rehabilitation after myocardial infarction (MI). In a nationwide trial of internet-delivered cognitive behavior therapy (iCBT) for the high-risk subgroup of patients with MI also reporting symptoms of anxiety, depression, or both (MI-ANXDEP), adherence w...

BACKGROUND: The heart school is an educational intervention offered in comprehensive cardiac rehabilitation (CR) in Sweden after suffering myocardial infarction (MI). The intervention aims to reduce modifiable risk factors and thereby also mortality and morbidity post-MI, yet has not been investigated with respect to hard endpoints. PURPOSE: We e...

BACKGROUND: Psychotherapeutic treatment for the subgroup of patients with MI that also suffer from comorbid symptoms of anxiety and/or depression (MI-ANXDEP) is part of cardiac rehabilitation (CR). Adherence to a range of treatments and lifestyle advice is crucial for risk reduction in these patients. Understanding the relative importance of predic...

BACKGROUND: Cognitive ability is substantially hereditary and predicts socioeconomic status (SES), health behaviours, physical health, and longevity. The robustness and mediation of the CA – mortality association is however insufficiently understood. Our previous findings suggest that the effect of early-in-life CA on later-in-life mortality also h...

BACKGROUND: Low adherence to recommended treatments is a multifactorial problem in rehabilitation for patients with myocardial infarction (MI). In a nationwide trial of internet-delivered cognitive behavior therapy (iCBT) for the high-risk subgroup of patients with MI also reporting symptoms of anxiety, depression, or both (MI-ANXDEP), adherence wa...

Supplemental material for Factors associated with emotional distress in patients with myocardial infarction: Results from the SWEDEHEART registry

BACKGROUND: Mild Cognitive Impairment (MCI) and dementia differ in important ways yet share a future of increased prevalence. Separating these conditions from each other, and from Subjective Cognitive Impairment (SCI), is important for clinical prognoses and treatment, socio-legal interventions, and family adjustments. With costly clinical investig...

Background Emotional distress, symptoms of depression and anxiety, is common among patients after a myocardial infarction (MI), and is associated with an increased risk of cardiovascular morbidity. Real world population data on factors associated with emotional distress in MI patients are scarce. The aim was to determine factors associated with inc...

BACKGROUND: Symptoms of depression and anxiety are common after a myocardial infarction (MI). Internet-based cognitive behavioral therapy (iCBT) has shown good results in other patient groups. OBJECTIVE: The aim of this study was to evaluate the effectiveness of an iCBT treatment to reduce self-reported symptoms of depression and anxiety among pat...

Background: General cognitive ability (CA) is positively associated with later physical and mental health, health literacy, and longevity. We investigated whether CA estimated approximately 30 years earlier in young adulthood predicted lifestyle-related risk factors and two-year survival in first myocardial infarction (MI) male patients. Methods:...

Poster presentation + abstract.

Introduction: Statin use after a myocardial infarction (MI) has been shown to effectively reduce cardiovascular events and mortality and is first line therapy. However, evidence shows suboptimal treatment adherence. Emotional distress (ED) has been found to affect adherence to cardiac medication, but less has been done to assess its influence in ad...

INTRODUCTION: General cognitive ability (CA) estimated early in life is positively associated with later physical and mental health, health literacy, and longevity. METHODS: We investigated young adulthood CA as a long-term risk indicator for the lifestyle factors smoking, diabetes, hypertension, obesity, and two-year mortality in the largest samp...

Introduction and purpose: Psychological stress may trigger a cardiovascular event, such as acute myocardial infarction (MI). Increased MI incidence coincides with recurrent time ­periods during the year perceived as particularly stressful. We evaluated an Artificial Time­-Constraint (ATC) model which postulates that the incidence of cardiovascular...

Physical prowess is associated with rapid recovery from exhaustion. Here we examined whether recovery from aerobic exercise could be manipulated with a rhythmic sound pattern that either decreased or increased in tempo. Six men and six women exercised repeatedly for 6 min on a cycle ergometer at 60 percent of their individual maximal oxygen consump...

The feminist movement purports to improve conditions for women, and yet only a minority of women in modern societies self-identify as feminists. This is known as the feminist paradox. It has been suggested that feminists exhibit both physiological and psychological characteristics associated with heightened masculinization, which may predispose wom...