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Mats LekanderProfessor

Om mig

Mats arbetar i skärningspunkten mellan psykologi och biomedicin. Framförallt studerar han samverkan mellan hjärnan och immunsystemet och beteendets roll i detta samspel. Detta kan exempelvis gälla effekter av stress eller otillräcklig sömn på immunsystemets och hjärnans funktion.

Flera relevanta studier är inriktade på allergi. Ett särskilt intresse ligger i hur immunsystemet påverkar hjärnans aktivitet och därigenom den subjektiva hälsoupplevelsen. Inom detta område studerar han hur både akut och kronisk inflammation påverkar smärtkänslighet, trötthet och så kallad självskattad hälsa. Mats intresse för mekanismer bakom generella hälsoaspekter och stress har de senaste åren också tillämpats inom behandlingsforskning, där flera studier pågår. Ett exempel är akupunktur och den roll placebo och interaktionen mellan behandlare och patient har för behandlingens effektivitet.

Andra studier gäller bland annat behandling av insomni eller hälsoångest (hypokondri) med hjälp av kognitiv beteendeterapi, eller hur ACT (Acceptance and Commitment Therapy) kan användas vid kroniska smärttillstånd. I nästan alla studier kompletterar biologiska och psykologiska observationsnivåer varandra för att ge ökad förståelse.

Mats är föreståndare för Stockholm Stress Center.


Psykologexamen 1990,
Doktor i medicinsk vetenskap 1996



I urval från Stockholms universitets publikationsdatabas

  • Anterior insula morphology and vulnerability to psychopathology-related symptoms in response to acute inflammation

    2022. Kristoffer N. T. Månsson (et al.). Brain, behavior, and immunity 99, 9-16


    Introduction: The role of inflammation in common psychiatric diseases is now well acknowledged. However, the factors and mechanisms underlying inter-individual variability in the vulnerability to develop psychopathology related symptoms in response to inflammation are not well characterized. Herein, we aimed at investigating morphological brain regions central for interoception and emotion regulation, and if these are associated with acute inflammation-induced sickness and anxiety responses.

    Methods: Systemic inflammation was induced using an intravenous injection of lipopolysaccharide (LPS) at a dose of 0.6 ng/kg body weight in 28 healthy individuals, while 21 individuals received an injection of saline (placebo). Individuals' gray matter volume was investigated by automated voxel-based morphometry technique on T1-weighted anatomical images derived from magnetic resonance imaging (MRI). Plasma concentrations of TNF alpha and IL-6, sickness symptoms (SicknessQ), and state anxiety (STAI-S) were measured before and after the injection.

    Results: A stronger sickness response to LPS was significantly associated with a larger anterior insula gray matter volume, independently from increases in cytokine concentrations, age, sex and body mass index (R-2 = 65.6%). Similarly, a greater LPS-induced state anxiety response was related to a larger anterior insula gray matter volume, and also by a stronger increase in plasma TNF-alpha concentrations (R-2 = 40.4%).

    Discussion: Anterior insula morphology appears central in the sensitivity to develop symptoms of sickness and anxiety in response to inflammation, and could thus be one risk factor in inflammation-related psychopathologies. Because of the limited sample size, the current results need to be replicated.

    Läs mer om Anterior insula morphology and vulnerability to psychopathology-related symptoms in response to acute inflammation
  • Acute Systemic Experimental Inflammation Does Not Reduce Human Odor Identification Performance

    2021. Arnaud Tognetti (et al.). Chemical Senses 46


    Olfactory dysfunction is a common symptom of various diseases, but the underlying pathophysiology has not been fully understood. Evidence from both animal and human studies suggests that local inflammation of the olfactory epithelium is linked to olfactory dysfunction. However, whether systemic inflammation causes olfactory dysfunction is yet to be determined. In the present behavioral study, we set out to test whether acute systemic inflammation impairs olfactory identification performance by inducing a transient and controlled state of systemic inflammation using an experimental endotoxemia model. We treated young healthy participants (N = 20) with a relatively high dose (2.0 ng/kg) of lipopolysaccharide (LPS) and a placebo treatment in a double-blind within-subject design, and assessed participants' ability to identify odors using the MONEX-40, a reliable method for experimental assessment of odor identification ability in healthy and young individuals. Our results show that olfactory identification performance was not affected by the acute systemic inflammation triggered by the injection of LPS. Moreover, odor identification performance following the LPS injection was not associated with levels of circulating proinflammatory cytokines (interleukin-6, interleukin-8, and tumor necrosis factor-alpha). Because experimental LPS-induced systemic inflammation does not affect olfactory identification performance, our findings suggest that chronic, rather than transient, systemic inflammation is a more likely mechanism to explore in order to explain the olfactory deficits observed in inflammatory diseases.

    Läs mer om Acute Systemic Experimental Inflammation Does Not Reduce Human Odor Identification Performance
  • Autistic Traits and Attention-Deficit Hyperactivity Disorder Symptoms Associated With Greater Pain Interference and Depression, and Reduced Health-Related Quality of Life in Children With Chronic Pain

    2021. Camilla Wiwe Lipsker (et al.). Frontiers in Neuroscience 15


    Previous research indicates elevated levels of clinically significant traits and symptoms of autism spectrum disorder and attention-deficit hyperactivity disorder (ADHD) in children with chronic pain, but associations with functioning and depression are yet unclear. The current study examined the relationships of autistic traits and ADHD symptoms with pain interference, depression, and health-related quality of life, as well as the mediating roles of insomnia and psychological inflexibility, in children with chronic pain (n = 146, 8-17 years, 102 girls) presenting at a tertiary pain clinic. Children completed measures of pain intensity, depression, pain interference, health-related quality of life, insomnia, and psychological inflexibility. Parents (n = 146, 111 mothers) completed measures to assess autistic traits and ADHD symptoms in their children. Children with clinically significant autistic traits and ADHD symptoms presented with significantly higher levels of depressive symptoms and pain interference, and significantly lower health-related quality of life, than did the other children. Autistic traits and ADHD symptoms contributed significantly to the prediction of pain interference and depressive symptoms, as well as health-related quality of life. Psychological inflexibility mediated the relationships between ADHD symptoms and autistic traits on the one hand and depression, pain interference, and health-related quality of life on the other, while insomnia mediated the relationships between ADHD symptoms and depression, pain interference, and health-related quality of life. All analyses were adjusted for demographics and pain intensity. Results suggest the utility of screening for neurodevelopmental disorders in children with chronic pain. Furthermore, the findings may indicate insomnia and skills related to psychological flexibility as potential treatment targets in interventions aiming at improving functioning and health-related quality of life in children with chronic pain and co-occurring symptoms of neurodevelopmental disorders.

    Läs mer om Autistic Traits and Attention-Deficit Hyperactivity Disorder Symptoms Associated With Greater Pain Interference and Depression, and Reduced Health-Related Quality of Life in Children With Chronic Pain
  • Cortical thickness and resting-state cardiac function across the lifespan

    2021. Julian Koenig (et al.). Psychophysiology 58 (7)


    Understanding the association between autonomic nervous system [ANS] function and brain morphology across the lifespan provides important insights into neurovisceral mechanisms underlying health and disease. Resting-state ANS activity, indexed by measures of heart rate [HR] and its variability [HRV] has been associated with brain morphology, particularly cortical thickness [CT]. While findings have been mixed regarding the anatomical distribution and direction of the associations, these inconsistencies may be due to sex and age differences in HR/HRV and CT. Previous studies have been limited by small sample sizes, which impede the assessment of sex differences and aging effects on the association between ANS function and CT. To overcome these limitations, 20 groups worldwide contributed data collected under similar protocols of CT assessment and HR/HRV recording to be pooled in a mega-analysis (N = 1,218 (50.5% female), mean age 36.7 years (range: 12–87)). Findings suggest a decline in HRV as well as CT with increasing age. CT, particularly in the orbitofrontal cortex, explained additional variance in HRV, beyond the effects of aging. This pattern of results may suggest that the decline in HRV with increasing age is related to a decline in orbitofrontal CT. These effects were independent of sex and specific to HRV; with no significant association between CT and HR. Greater CT across the adult lifespan may be vital for the maintenance of healthy cardiac regulation via the ANS—or greater cardiac vagal activity as indirectly reflected in HRV may slow brain atrophy. Findings reveal an important association between CT and cardiac parasympathetic activity with implications for healthy aging and longevity that should be studied further in longitudinal research.

    Läs mer om Cortical thickness and resting-state cardiac function across the lifespan
  • Human sickness detection is not dependent on cultural experience

    2021. Artin Arshamian (et al.). Proceedings of the Royal Society of London. Biological Sciences 288 (1954)


    Animals across phyla can detect early cues of infection in conspecifics, thereby reducing the risk of contamination. It is unknown, however, if humans can detect cues of sickness in people belonging to communities with whom they have limited or no experience. To test this, we presented Western faces photographed 2 h after the experimental induction of an acute immune response to one Western and five non-Western communities, including small-scale hunter-gatherer and large urban-dwelling communities. All communities could detect sick individuals. There were group differences in performance but Western participants, who observed faces from their own community, were not systematically better than all non-Western participants. At odds with the common belief that sickness detection of an out-group member should be biased to err on the side of caution, the majority of non-Western communities were unbiased. Our results show that subtle cues of a general immune response are recognized across cultures and may aid in detecting infectious threats.

    Läs mer om Human sickness detection is not dependent on cultural experience
  • Neuropsychiatric Symptoms in Pediatric Chronic Pain and Outcome of Acceptance and Commitment Therapy

    2021. Leonie J. T. Balter (et al.). Frontiers in Psychology 12


    Considerable heterogeneity among pediatric chronic pain patients may at least partially explain the variability seen in the response to behavioral therapies. The current study tested whether autistic traits and attention-deficit/hyperactivity disorder (ADHD) symptoms in a clinical sample of children and adolescents with chronic pain are associated with socioemotional and functional impairments and response to acceptance and commitment therapy (ACT) treatment, which has increased psychological flexibility as its core target for coping with pain and pain-related distress. Children and adolescents aged 8-18 years (N = 47) were recruited. Patients and their parents completed questionnaires pre- and post-ACT of 17 sessions. Correlational analyses and mixed-effects models were used to assess the role of autistic traits and ADHD symptoms in pretreatment functioning and ACT-treatment response. Outcome variables were degree to which pain interfered with daily activities (i.e., pain interference, sleep, and physical and school functioning), socioemotional functioning (i.e., depressive symptoms, emotional, and social functioning), psychological inflexibility, and pain intensity. Autistic traits and ADHD symptoms, pain frequency, and pain duration were measured at pretreatment only. Higher autistic traits were associated with greater pain interference, higher depression, and greater psychological inflexibility. Higher ADHD symptomatology was associated with greater pretreatment pain interference, lower emotional functioning, greater depression, and longer duration of pain. Across patients, all outcome variables, except for sleep disturbances and school functioning, significantly improved from pre- to post-ACT. Higher autistic traits were associated with greater pre- to post-ACT improvements in emotional functioning and sleep disturbance and non-significant improvements in pain interference. ADHD symptomatology was not associated with treatment outcome. The current results showed that neuropsychiatric symptoms in pediatric chronic pain patients are associated with lower functioning, particularly pain interfering with daily life and lower socioemotional functioning. The results suggest that not only pediatric chronic pain patients low in neuropsychiatric symptoms may benefit from ACT, but also those high in autism traits and ADHD symptoms. With the present results in mind, pediatric chronic pain patients higher in autistic traits may actually derive extra benefit from ACT. Future research could assess whether increased psychological flexibility, the core focus of ACT, enabled those higher in autism traits to cope relatively better with pain-related distress and thus to gain more from the treatment, as compared to those lower in autism traits. Moreover, to address specific effects of ACT, inclusion of an appropriate control group is key.

    Läs mer om Neuropsychiatric Symptoms in Pediatric Chronic Pain and Outcome of Acceptance and Commitment Therapy
  • Objective and Subjective Sleep in Rheumatoid Arthritis and Severe Seasonal Allergy

    2021. Sandra Tamm (et al.). Nature and Science of Sleep 13, 775-789


    Introduction: Disturbed sleep in inflammatory disorders such as allergy and rheumatoid arthritis (RA) is common and may be directly or indirectly related to disease processes, but has not been well characterized in these patient groups, especially not with objective methods.

    Aim: The present study aimed to characterize objective and subjective sleep in patients with allergy or RA using sleep diaries, one-channel EEG and actigraphy. It also aimed to investigate if sleep measures were associated with central immune activation, assessed using translocator protein (TSPO) positron emission tomography, as well as cytokine markers of peripheral inflammation and disease-specific symptoms or general symptoms of sickness.

    Methods: In total, 18 patients with seasonal pollen allergy, 18 patients with RA and 26 healthy controls were included in the study. Allergy patients and matched controls were assessed twice, in and out of pollen season, and RA patients and controls were assessed once. Sleep was recorded for approximately 1 week at each occasion.

    Results: Patients with allergy had increased levels of slow-wave sleep during pollen season. In contrast, patients with RA had less SWS compared to healthy controls, while no differences were observed in sleep duration or subjective sleep quality. Across groups, neither proinflammatory cytokines, grey matter TSPO levels nor general sickness symptoms were associated with objective or subjective measures of sleep. Rhinitis, but not conjunctivitis, was correlated to worse subjective sleep and more slow wave sleep in allergy. Functional status, but not disease activity, predicted lower subjective sleep in RA.

    Conclusion: This study tentatively indicates that both patients with allergy and RA display sleep alterations but does not support inflammation as an independent predictor of the sleep disturbance across these patient groups.

    Läs mer om Objective and Subjective Sleep in Rheumatoid Arthritis and Severe Seasonal Allergy
  • Regulation of emotions during experimental endotoxemia

    2021. Lina S. Hansson (et al.). Brain, behavior, and immunity 93, 420-424


    Even though dysfunctional emotion regulation is prominent in depression and a link between depression and inflammation is well established, there is little knowledge about how inflammation affects the regulation of emotions. The aim of this pilot study was to explore the effect of experimentally induced inflammation on the cognitive reappraisal of emotions, and to assess domain specificity by comparing success in regulation of emotions towards two unpleasant stimuli classes (general negative stimuli and disgust stimuli). In a between-subject design, ten healthy participants were injected with an intravenous injection of lipopolysaccharide (2 ng/kg body weight) and eleven were injected with saline. Participants performed a cognitive reappraisal task, in which they had to down-regulate or up-regulate their emotions towards general negative stimuli and disgust stimuli, 5–6 h post-injection. Contrary to our hypotheses, participants injected with lipopolysaccharide reported greater success in down-regulating emotional responses towards unpleasant stimuli as compared to the saline group. In addition, both groups were poorer at down-regulating emotions towards disgust stimuli as compared to general negative stimuli. The current pilot study indicates that cognitive reappraisal of emotions is affected during experimental endotoxemia, and suggests that disgust stimuli might be difficult to reappraise.

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  • The mediating role of insomnia severity in internet-based cognitive behavioral therapy for chronic stress

    2021. Elin Lindsäter (et al.). Behaviour Research and Therapy 136


    The aim of this study was to investigate insomnia symptom severity as a putative mediator of treatment response in therapist-guided internet-based cognitive behavioral therapy (ICBT) for chronic stress, using data from a randomized controlled trial. Participants (N = 100) were randomized to 12 weeks of ICBT or to a waitlist control condition (WLC). Insomnia severity was assessed weekly with the Insomnia Severity Index (ISI), as were the stress-related outcomes the Perceived Stress Scale (PSS) and the Shirom-Melamed Burnout Questionnaire (SMBQ). Latent growth models indicated that ICBT (vs. WLC) predicted a decrease in insomnia severity (alpha-path), and that growth in insomnia severity was predictive of growth in perceived stress and exhaustion (beta-paths). Most importantly, there were also significant indirect effects (alpha beta products) such that the beneficial effects of ICBT on perceived stress and exhaustion were mediated by a reduction in insomnia symptom severity (PSS: alpha beta =-0.44, 95% CI [-0.92,-0.14]; SMBQ: alpha beta =-0.08, 95% CI [-0.15, 0.04]). Explorative analysis of moderated mediation showed that more severe insomnia symptoms at baseline were associated with larger mediated effects. We conclude that reducing insomnia severity could be of importance for achieving successful treatment outcomes in ICBT for chronic stress.

    Läs mer om The mediating role of insomnia severity in internet-based cognitive behavioral therapy for chronic stress
  • Vulnerability in Executive Functions to Sleep Deprivation Is Predicted by Subclinical Attention-Deficit/Hyperactivity Disorder Symptoms

    2021. Orestis Floros (et al.). Biological Psychiatry 6 (3), 290-298


    Background: Sleep loss results in state instability of cognitive functioning. It is not known whether this effect is more expressed when there is an increased cognitive demand. Moreover, while vulnerability to sleep loss varies substantially among individuals, it is not known why some people are more affected than others. We hypothesized that top-down regulation was specifically affected by sleep loss and that subclinical inattention and emotional instability traits, related to attention-deficit/hyperactivity disorder symptoms, predict this vulnerability in executive function and emotion regulation, respectively.

    Methods: Healthy subjects (ages 17–45 years) rated trait inattention and emotional instability before being randomized to either a night of normal sleep (n = 86) or total sleep deprivation (n = 87). Thereafter, they performed a neutral and emotional computerized Stroop task, involving words and faces. Performance was characterized primarily by cognitive conflict reaction time and reaction time variability (RTV), mirroring conflict cost in top-down regulation.

    Results: Sleep loss led to increased cognitive conflict RTV. Moreover, a higher level of inattention predicted increased cognitive conflict RTV in the neutral Stroop task after sleep deprivation (r = .30, p = .0055) but not after normal sleep (r = .055, p = .65; interaction effect β = 6.19, p = .065). This association remained after controlling for cognitive conflict reaction time and emotional instability, suggesting domain specificity. Correspondingly, emotional instability predicted cognitive conflict RTV for the emotional Stroop task only after sleep deprivation, although this effect was nonsignificant after correcting for multiple comparisons.

    Conclusions: Our findings suggest that sleep deprivation affects cognitive conflict variability and that less stable performance in executive functioning may surface after sleep loss in vulnerable individuals characterized by subclinical symptoms of inattention.

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  • Work ability and psychological distress in a working population

    2021. Clara Onell (et al.). Scandinavian Journal of Public Health


    Aims: Psychological distress is a global public health concern with individual and societal implications causing work-related disability and loss of productivity. It is less known how much work ability contributes to the development of psychological distress. This study aimed to assess the association between self-perceived physical and mental work ability in relation to job demands, and the incidence of psychological distress in a Swedish working population.

    Methods: Data were obtained from three subsamples of the Stockholm Public Health Cohort with baseline in 2010 and follow-up in 2014, based on a working population in Stockholm County aged 18–60 years, with no or mild psychological distress at baseline (n=29,882). Self-perceived physical and mental work ability in relation to job demands were assessed at baseline with a subscale from the Work Ability Index. Study participants scoring 4 or more on the General Health Questionnaire 12 at follow-up were classified as having developed psychological distress during the study period. Poisson log linear regression was used to calculate crude and adjusted rate ratios with 95% confidence intervals.

    Results: At follow-up, 2543 participants (12%) had developed psychological distress. Reporting poor physical and/or poor mental work ability in relation to job demands at baseline was associated with an almost doubled rate ratio of psychological distress at follow-up, compared to reporting good work ability (rate ratio 1.8; 95% confidence interval 1.6–2.0).

    Conclusions: Poor work ability is associated with a higher incidence of future psychological distress compared to good work ability.

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Visa alla publikationer av Mats Lekander vid Stockholms universitet