Marie Eikemo

• Meier, Isabell M.; Trøstheim, Martin Ostenfeldt; Jensen, Eira Nordeng; Roland, Mathias Nikolai; Løseth, Guro Engvig & Eikemo, Marie [Show all 7 contributors for this article] (2026). Minor role of endogenous opioids for acute pain regulation in humans: a systematic review and meta-analysis of placebo-controlled antagonist studies. Pain. ISSN 0304-3959. doi: 10.1097/j.pain.0000000000004097. Full text in Research Archive
• Eikemo, Marie; Løseth, Guro Engvig; Carlyle, Molly; Trøstheim, Martin Ostenfeldt; Ernst, Gernot Walter & Pazmandi, Claudia [Show all 14 contributors for this article] (2026). Effects of psychosocial stress on opioid self-administration in healthy participants: a randomized, placebo-controlled crossover trial. Nature Mental Health. doi: 10.1038/s44220-026-00700-x. Full text in Research Archive
• Trøstheim, Martin Ostenfeldt; Pedersen, Mads Lund; Leknes, Siri; Hama, Lennja Majid; Roland, Mathias Nikolai & Lobmaier, Philipp Paul [Show all 10 contributors for this article] (2025). Reward Sensitivity in Patients Receiving Opioid Agonist and Antagonist Treatment for Opioid Use Disorder: An Observational Study. Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. ISSN 2451-9022. 10(11), p. 1166–1176. doi: 10.1016/j.bpsc.2025.04.013. Full text in Research Archive Show summary

  Background Disrupted reward processing is a core component in neurobiological theories of addictions, including opioid use disorder (OUD). While acute opioid agonist and antagonist administration can modulate reward behavior and experiences, it remains unclear how typical long-term OUD treatment with these medications impacts patients’ sensitivity to substance-free rewards. Therefore, we conducted a cross-sectional study of reward sensitivity in opioid agonist– and antagonist–treated patients with OUD and healthy volunteers. Methods Ninety-six patients with OUD on extended-release naltrexone (n = 45) or opioid agonists (n = 51) and 50 healthy volunteers completed a probabilistic reward task (PRT) and self-report measures of anhedonia, depression, preoccupation with immediate consequences, substance craving, and life satisfaction in a single session. We used signal detection analysis and drift diffusion modeling to derive behavioral reward bias measures from PRT performance. Group differences were modeled with beta and linear regression. Results Patients reported significantly greater anhedonia (Cohen’s ds ≥ 0.64), depression (ds ≥ 0.53), and preoccupation with immediate consequences (ds ≥ 0.54) than healthy volunteers, but differences between naltrexone- and opioid agonist–treated patients were nonsignificant (ds ≤ 0.26). Group differences in behavioral reward bias were small and nonsignificant (ps = 1, Bayes factor [BF]01s ≥ 84.13). Anhedonia was significantly associated with lower life satisfaction (odds ratio [95% CI], 1.10 [1.04 to 1.17]). There were no other significant associations between reward sensitivity measures and life satisfaction or craving (ps ≥ .31, BF01s ≥ 2.58). Conclusions These data support an association between OUD and reduced well-being irrespective of opioid agonist or antagonist treatment, highlighting patients’ need for psychosocial support and/or adjunct interventions. Major detrimental effects of naltrexone treatment on well-being seem unlikely from these and previous results.

• Løseth, Guro Engvig; Eikemo, Marie & Leknes, Siri (2025). Opioid Regulation of Social Homeostasis: Connecting Loneliness to Addiction. Biological Psychiatry. ISSN 0006-3223. 97(10), p. 971–981. doi: 10.1016/j.biopsych.2024.11.011. Full text in Research Archive
• Trøstheim, Martin Ostenfeldt & Eikemo, Marie (2024). Hyperalgesia in Patients With a History of Opioid Use Disorder: A Systematic Review and Meta-Analysis. JAMA psychiatry. ISSN 2168-6238. doi: 10.1001/jamapsychiatry.2024.2176. Full text in Research Archive
• Carlyle, Molly; Kvande, Malin; Meier, Isabell M.; Trøstheim, Martin Ostenfeldt; Buen, Kaja & Jensen, Eira Nordeng [Show all 9 contributors for this article] (2023). Does childhood adversity alter opioid drug reward? A conceptual replication in outpatients before surgery. Addiction Research and Theory. ISSN 1606-6359. doi: 10.1080/16066359.2023.2211348. Full text in Research Archive
• Eikemo, Marie; Meier, Isabell M.; Løseth, Guro Engvig; Trøstheim, Martin Ostenfeldt; Ørstavik, Nikoline & Jensen, Eira Nordeng [Show all 10 contributors for this article] (2023). Opioid analgesic effects on subjective well-being in the operating theatre*. Anaesthesia. ISSN 0003-2409. 78(9), p. 1102–1111. doi: 10.1111/anae.16069. Full text in Research Archive
• Meier, Isabell M.; Eikemo, Marie; Trøstheim, Martin Ostenfeldt; Buen, Kaja; Jensen, Eira Nordeng & Karlsen, Siri Gurandsrud [Show all 10 contributors for this article] (2023). Factors associated with use of opioid rescue medication after surgery. Regional anesthesia and pain medicine. ISSN 1098-7339. doi: 10.1136/rapm-2023-104412. Full text in Research Archive
• Trøstheim, Martin; Eikemo, Marie; Haaker, Jan; Frost, J. James & Leknes, Siri (2022). Opioid antagonism in humans: a primer on optimal dose and timing for central mu-opioid receptor blockade. Neuropsychopharmacology. ISSN 0893-133X. p. 1–9. doi: 10.1038/s41386-022-01416-z. Full text in Research Archive
• Sarfi, Annamaria Monika; Eikemo, Marie & Konijnenberg, Carolien (2022). Children born to women in opioid maintenance treatment: A longitudinal study of child behavioral problems and parenting stress. Frontiers in Pediatrics. 10. doi: 10.3389/fped.2022.1087956. Full text in Research Archive Show summary

  In the wake of the “opioid epidemic”, there is considerable concern regarding potential harmful long-term effects of prenatal opioid exposure. Opioid misuse and addiction confer increased exposure to lifestyle stressors and health burdens. Accordingly, it is challenging to disentangle effects of prenatal opioid exposure per se from factors related to maternal stress. In this study, we followed 36 women enrolled in comprehensive opioid maintenance treatment (OMT) program and their children alongside 36 age-matched mother-child dyads from a community sample (COMP) from pregnancy until child-age 8 years. Across five sessions, we used a battery of well-established questionnaires to investigate trajectories of parenting stress and mental health symptoms as well as child behavior problems. The 8-year retention was relatively high (OMT: 72%, COMP: 67%), and the OMT sample remarkably stable and well-functioning, with minimal concomitant illicit drug use. Mixed effects regressions showed significantly different trajectories of child behavior problems (F = 3.8, p = 0.024) and parenting stress (F = 3.1, p = 0.016) in the two groups. Differences in experienced stress were largely explained by more distress specifically related to the parenting role in the OMT group (F = 9.7, p = 0.003). The OMT sample also reported higher psychological distress (F = 15.6, p < 0.001) than the comparison group, but notably few participants presented with problems that warranted clinical intervention. The results underscore the benefits of tailored follow-up of children prenatally exposed to opioids and their families beyond infancy and toddlerhood. Long-term direct effects of prenatal opioid exposure on behavior problems are likely modest, given an otherwise stable caregiving environment conducive to healthy development.

• Løseth, Guro Engvig; Eikemo, Marie; Trøstheim, Martin; Meier, Isabell M.; Bjørnstad, Herman & Asratian, Anna [Show all 10 contributors for this article] (2022). Stress recovery with social support: A dyadic stress and support task. Psychoneuroendocrinology. ISSN 0306-4530. 146. doi: 10.1016/j.psyneuen.2022.105949. Full text in Research Archive Show summary

  How does social support bolster resilience? Here, we present a new dyadic paradigm to study causal mechanisms of acute and ecologically valid social support in the laboratory. The Dyadic Stress and Support Task (DSST) consists of a psychosocial stress phase and a recovery phase. During DSST stress, a pair of participants take turns to perform public speaking and mental arithmetic in front of a panel. Unable to see or touch each other, they witness each other’s performance and feedback. During DSST recovery, the pair either interact freely with each other for 5 min (social support condition) or interact separately with an experimenter (non-support condition). To establish the validity of the DSST, we tested 21 pairs of long-term close friends in a pilot study. Primary outcome measures were ratings of affective state and bodily arousal (VAS scales 0–100). Secondary outcome measures were heart rate and salivary cortisol. DSST stress successfully induced subjective Stress Activation, increased Negative Affect and decreased Positive Affect. We also observed increased heart rate and salivary cortisol. After DSST recovery, Stress Activation and Negative Affect ratings were reduced in both groups. Positive Affect was completely restored to pre-stress baseline levels in the Social support group, while remaining significantly lower in the Non-support group. The DSST successfully induced stress and negative affect and captured stress recovery in both groups. Free-form interaction with the friend enhanced recovery of affective state, supporting the validity of spontaneous interaction between friends as a model of social support.

• Meier, Isabell M.; Eikemo, Marie & Leknes, Siri (2021). The Role of Mu-Opioids for Reward and Threat Processing in Humans: Bridging the Gap from Preclinical to Clinical Opioid Drug Studies. Current Addiction Reports. p. 1–13. doi: 10.1007/s40429-021-00366-8. Full text in Research Archive
• Henningsson, Susanne; Leknes, Siri; Asperholm, Martin; Eikemo, Marie & Westberg, Lars (2021). A randomized placebo-controlled intranasal oxytocin study on first impressions and reactions to social rejection. Biological Psychology. ISSN 0301-0511. doi: 10.1016/j.biopsycho.2021.108164. Full text in Research Archive
• Laeng, Bruno; Garvija, Lara; Løseth, Guro Engvig; Eikemo, Marie; Ernst, Gernot & Leknes, Siri (2021). ‘Defrosting’ music chills with naltrexone: The role of endogenous opioids for the intensity of musical pleasure. Consciousness and Cognition. ISSN 1053-8100. 90. doi: 10.1016/j.concog.2021.103105. Full text in Research Archive
• Sarfi, Annamaria Monika; Eikemo, Marie; Welle-Strand, Gabrielle; Muller, Ashley Elizabeth & Lehmann, Stine (2021). Mental health and use of health care services in opioid‑exposed school‑aged children compared to foster children. European Child and Adolescent Psychiatry. ISSN 1018-8827. p. 1–15. doi: 10.1007/s00787-021-01728-3. Full text in Research Archive Show summary

  Given the concerns raised regarding the effects of prenatal exposure to methadone and buprenorphine on the developmental outcomes of the children, this study assessed mental health and use of services in a national sample of school-aged children (N = 78) born to women enrolled in opioid maintenance treatment during pregnancy, compared with a group of foster children (N = 140). The majority of the opioid-exposed children lived with their birth parent(s) at the time of assessment (N = 62), while 16 lived in foster homes. Caregivers completed the Strengths and Difficulties Questionnaire (SDQ) and the Reactive Attachment Disorder scale. Teachers completed the SDQ. Three kinds of services were included in measuring service use: school-based education services, child mental health services, and hospital-based habilitation services. The main finding of the study is that children prenatally exposed to methadone or buprenorphine living with their family of origin had significantly better mental health status than their foster-placed counterparts and that of the comparison group of foster children. In addition, the exposed children living at home had less child welfare involvement, and only half of them were using any of the three services measured. The odds for using services increased significantly in accordance with increasing mental health problems, independent of group affiliation, indicating a need-based access to services. In line with other studies, we found that the odds for using one or more services was 2.3 times greater for boys than for girls. Our results contribute to a more-nuanced understanding of the developmental outcomes of prenatal exposure to methadone and buprenorphine, and factors associated with increased service use in groups of at-risk children.

• Trøstheim, Martin; Eikemo, Marie; Meir, Remy; Hansen, Ingelin; Paul, Elisabeth & Kroll, Sara Liane [Show all 8 contributors for this article] (2020). Assessment of Anhedonia in Adults With and Without Mental Illness A Systematic Review and Meta-analysis. JAMA Network Open. 3(8). doi: 10.1001/jamanetworkopen.2020.13233. Full text in Research Archive Show summary

  Importance Anhedonia, a reduced capacity for pleasure, is described for many psychiatric and neurologic conditions. However, a decade after the Research Domain Criteria launch, whether anhedonia severity differs between diagnoses is still unclear. Reference values for hedonic capacity in healthy humans are also needed. Objective To generate and compare reference values for anhedonia levels in adults with and without mental illness. Data Sources Web of Science, Scopus, PubMed, and Google Scholar were used to list all articles from January 1, 1995 to July 2, 2019, citing the scale development report of a widely used anhedonia questionnaire, the Snaith-Hamilton Pleasure Scale (SHAPS). Searches were conducted from April 5 to 11, 2018, and on July 2, 2019. Study Selection Studies including healthy patients and those with a verified diagnosis, assessed at baseline or in a no-treatment condition with the complete 14-item SHAPS, were included in this preregistered meta-analysis. Data Extraction and Synthesis Random-effects models were used to calculate mean SHAPS scores and 95% CIs separately for healthy participants and patients with current major depressive disorder (MDD), past/remitted MDD, bipolar disorder, schizophrenia, substance use disorders, Parkinson disease, and chronic pain. SHAPS scores were compared between groups using meta-regression, and traditional effect size meta-analyses were conducted to estimate differences in SHAPS scores between healthy and patient samples. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Main Outcomes and Measures Self-reported anhedonia as measured by 2 different formats of the SHAPS (possible ranges, 0-14 and 14-56 points), with higher values on both scales indicating greater anhedonia symptoms. Results In the available literature (168 articles; 16 494 participants; 8058 [49%] female participants; aged 13-72 years), patients with current MDD, schizophrenia, substance use disorder, Parkinson disease, and chronic pain scored higher on the SHAPS than healthy participants. Within the patient groups, those with current MDD scored considerably higher than all other groups. Patients with remitted MDD scored within the healthy range (g = 0.1). This pattern replicated across SHAPS scoring methods and was consistent across point estimate and effect size analyses. Conclusions and Relevance The findings of this meta-analysis indicate that the severity of anhedonia may differ across disorders associated with anhedonia. Whereas anhedonia in MDD affects multiple pleasure domains, patients with other conditions may experience decreased enjoyment of only a minority of life’s many rewards. These findings have implications for psychiatric taxonomy development, where dimensional approaches are gaining attention. Moreover, the SHAPS reference values presented herein may be useful for researchers and clinicians assessing the efficacy of anhedonia treatments.

• Eikemo, Marie; Lobmaier, Philipp Paul; Pedersen, Mads Lund; Kunøe, Nikolaj; Matziorinis, Anna Maria & Leknes, Siri [Show all 7 contributors for this article] (2019). Intact responses to non-drug rewards in long-term opioid maintenance treatment. Neuropsychopharmacology. ISSN 0893-133X. 44(8), p. 1456–1463. doi: 10.1038/s41386-019-0377-9. Full text in Research Archive Show summary

  Disruption of non-drug reward processing in addiction could stem from long-term drug use, addiction-related psychosocial stress, or a combination of these. It remains unclear whether long-term opioid maintenance treatment (OMT) disrupts reward processing. Here, we measured subjective and objective reward responsiveness in 26 previously heroin-addicted mothers in >7 years stable OMT with minimal psychosocial stress and illicit drug use. The comparison group was 30 healthy age-matched mothers (COMP). Objective reward responsiveness was assessed in a two-alternative forced-choice task with skewed rewards. Results were also compared to performance from an additional 968 healthy volunteers (meta-analytic approach). We further compared subprocesses of reward-based decisions across groups using computational modelling with a Bayesian drift diffusion model of decision making. Self-reported responsiveness to non-drug rewards was high for both groups (means: OMT = 6.59, COMP = 6.67, p = 0.84, BF10 = 0.29), yielding moderate evidence against subjective anhedonia in this OMT group. Importantly, the mothers in OMT also displayed robust reward responsiveness in the behavioral task (t19 = 2.72, p = 0.013, BF10 = 3.98; d = 0.61). Monetary reward changed their task behavior to the same extent as the local comparison group (reward bias OMT = 0.12, COMP = 0.12, p = 0.96, BF10 = 0.18) and in line with data from 968 healthy controls previously tested. Computational modelling revealed that long-term OMT did not even change decision subprocesses underpinning reward behavior. We conclude that reduced sensitivity to rewards and anhedonia are not necessary consequences of prolonged opioid use.

• Garland, Eric; Trøstheim, Martin; Eikemo, Marie; Ernst, Gernot & Leknes, Siri (2019). Anhedonia in chronic pain and prescription opioid misuse. Psychological Medicine. ISSN 0033-2917. p. 1–12. doi: 10.1017/S0033291719002010. Full text in Research Archive
• Løseth, Guro Engvig; Eikemo, Marie & Leknes, Siri (2019). Effects of opioid receptor stimulation and blockade on touch pleasantness: a double-blind randomised trial. Social Cognitive & Affective Neuroscience. ISSN 1749-5016. 14(4), p. 411–422. doi: 10.1093/scan/nsz022. Full text in Research Archive Show summary

  The μ-opioid receptor (MOR) system has long been thought to underpin the rewarding properties of pleasant touch. Numerous non-human animal studies implicate MORs in social behaviours involving touch, but little is currently known about MOR involvement in human touch reward. Here, we employed a bi-directional pharmacological double-blind crossover design to assess the role of the human MOR system for touch pleasantness and motivation. Forty-nine male volunteers received 10 mg per-oral morphine, 50 mg per-oral naltrexone and placebo before being brushed on their forearm at three different velocities (0.3, 3 and 30 cm/s). In a touch liking task, pleasantness ratings were recorded after each 15 s brushing trial. In a touch wanting task, participants actively manipulated trial duration through key presses. As expected, 3 cm/s was the preferred velocity, producing significantly higher pleasantness ratings and wanting scores than the other stimuli. Contrary to our hypothesis, MOR drug manipulations did not significantly affect either touch pleasantness or wanting. The null effects were supported by post hoc Bayesian analyses indicating that the models with no drug effect were more than 25 times more likely than the alternative models given the data. We conclude that μ-opioid signalling is unlikely to underpin non-affiliative touch reward in humans.

• Steenbergen, Henk van; Eikemo, Marie & Leknes, Siri (2019). The role of the opioid system in decision making and cognitive control: A review. Cognitive, Affective, & Behavioral Neuroscience. ISSN 1530-7026. 19(3), p. 435–458. doi: 10.3758/s13415-019-00710-6. Full text in Research Archive Show summary

  The opioid system regulates affective processing, including pain, pleasure, and reward. Restricting the role of this system to hedonic modulation may be an underestimation, however. Opioid receptors are distributed widely in the human brain, including the more “cognitive” regions in the frontal and parietal lobes. Nonhuman animal research points to opioid modulation of cognitive and decision-making processes. We review emerging evidence on whether acute opioid drug modulation in healthy humans can influence cognitive function, such as how we choose between actions of different values and how we control our behavior in the face of distracting information. Specifically, we review studies employing opioid agonists or antagonists together with experimental paradigms of reward-based decision making, impulsivity, executive functioning, attention, inhibition, and effort. Although this field is still in its infancy, the emerging picture suggests that the mu-opioid system can influence higher-level cognitive function via modulation of valuation, motivation, and control circuits dense in mu-opioid receptors, including orbitofrontal cortex, basal ganglia, amygdalae, anterior cingulate cortex, and prefrontal cortex. The framework that we put forward proposes that opioids influence decision making and cognitive control by increasing the subjective value of reward and reducing aversive arousal. We highlight potential mechanisms that might underlie the effects of mu-opioid signaling on decision making and cognitive control and provide directions for future research.

• Løseth, Guro Engvig; Eikemo, Marie Helene; Isager, Peder Mortvedt; Holmgren, Jostein; Laeng, Bruno & Vindenes, Vigdis [Show all 8 contributors for this article] (2018). Morphine reduced perceived anger from neutral and implicit emotional expressions. Psychoneuroendocrinology. ISSN 0306-4530. 91, p. 123–131. doi: 10.1016/j.psyneuen.2018.02.035. Full text in Research Archive Show summary

  The μ-opioid system modulates responses to pain and psychosocial stress and mediates non-social and social reward. In humans, the μ-opioid agonist morphine can increase overt attention to the eye-region and visual exploration of faces with neutral expressions. However, little is known about how the human μ-opioid system influences sensitivity to and appraisal of subtle and explicit cues of social threats and reward. Here, we examined the effects of selective μ-opioid stimulation on perception of anger and happiness in faces with explicit, neutral or implicit emotion expressions. Sixty-three healthy adults (32 females) attended two sessions where they received either placebo or 10 mg per oral morphine in randomised order under double-blind conditions. Based on the known μ-opioid reduction of pain and discomfort, as well as reports suggesting that the non-specific partial agonist buprenorphine or the non-specific antagonist naltrexone affect appraisal of social emotional stimuli, we hypothesised that morphine would reduce threat sensitivity and enhance perception of happy facial expressions. While overall perception of others’ happiness was unaffected by morphine treatment, morphine reduced perception of anger in stimuli with neutral and implicit expressions without affecting perception of explicit anger. This effect was statistically unrelated to gender, subjective drug effects, mood and autism trait measures. The finding that a low dose of μ-agonist reduced the propensity to perceive anger in photos with subtle facial expressions is consistent with the notion that μ-opioids mediate social confidence and reduce sensitivity to threat cues.

• Eikemo, Marie Helene; Biele, Guido; Willoch, Frode; Thomsen, Lotte & Leknes, Siri (2017). Opioid modulation of value-based decision-making in healthy humans. Neuropsychopharmacology. ISSN 0893-133X. 42(9), p. 1833–1840. doi: 10.1038/npp.2017.58. Full text in Research Archive
• Chelnokova, Olga V; Laeng, Bruno; Løseth, Guro Engvig; Eikemo, Marie Helene; Willoch, Frode & Leknes, Siri (2016). The µ-Opioid System Promotes Visual Attention to Faces and Eyes. Social Cognitive & Affective Neuroscience. ISSN 1749-5016. 11(12), p. 1902–1909. doi: 10.1093/scan/nsw116. Full text in Research Archive
• Eikemo, Marie Helene; Løseth, Guro Engvig; Johnstone, Tom; Gjerstad, Johannes; Willoch, Frode & Leknes, Siri (2016). Sweet taste pleasantness is modulated by morphine and naltrexone. Psychopharmacology. ISSN 0033-3158. 233(21), p. 13711–3723. doi: 10.1007/s00213-016-4403-x. Full text in Research Archive Show summary

  Background: Rodent models highlight the key role of μ-opioid receptor (MOR) signaling in palatable food consumption. In humans, however, the effects of MOR stimulation on eating and food liking remain unclear. Objectives Here, we tested sweet pleasantness experience in humans following MOR drug manipulations. We hypothesized that behaviors regulated by the endogenous MOR system would be enhanced by MOR agonism and decreased by antagonism. In line with rodent findings, we expected the strongest drug effects for the sweetest (high-calorie) sucrose stimuli. As very sweet stimuli are considered aversive by many people (called sweet dislikers), we also assessed whether MOR manipulations affect pleasantness ratings of sucrose-water stimuli differently depending on subjective and objective value. Methods: In a bidirectional psychopharmacological cross-over study, 49 healthy men underwent a sweet taste paradigm following double-blind administration of the MOR agonist morphine, placebo, and the opioid antagonist naltrexone. Results: As hypothesized, MOR stimulation with morphine increased pleasantness of the sweetest of five sucrose solutions, without enhancing pleasantness of the lower-sucrose solutions. For opioid antagonism, an opposite pattern was observed for the sweetest drink only. The observed drug effects on pleasantness of the sweetest drink did not differ between sweet likers and dislikers. Conclusions: The bidirectional effect of agonist and antagonist treatment aligns with rodent findings showing that MOR manipulations most strongly affect the highest-calorie foods. We speculate that the MOR system promotes survival in part by increasing concordance between the objective (caloric) and subjective (hedonic) value of food stimuli, so that feeding behavior becomes more focused on the richest food available.

• Chelnokova, Olga V; Laeng, Bruno; Eikemo, Marie; Riegels, Jeppe Kjær; Løseth, Guro Engvig & Maurud, Hedda [Show all 8 contributors for this article] (2014). Rewards of beauty: the opioid system mediates social motivation in humans. Molecular Psychiatry. ISSN 1359-4184. doi: 10.1038/mp.2014.1. Full text in Research Archive
• Ellingsen, Dan Mikael; Wessberg, Johan; Eikemo, Marie Helene; Liljencrantz, Jaquette; Endestad, Tor & Olausson, Håkan [Show all 7 contributors for this article] (2013). Placebo improves pleasure and pain through opposite modulation of sensory processing. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 110(44), p. 17993–17998. doi: 10.1073/pnas.1305050110. Full text in Research Archive

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• Eikemo, Marie; Løseth, Guro Engvig & Leknes, Siri (2021). Do endogenous opioids mediate or fine-tune human pain relief? Pain. ISSN 0304-3959. 162(12), p. 2789–2791. doi: 10.1097/j.pain.0000000000002286. Full text in Research Archive
• Løseth, Guro; Eikemo, Marie & Leknes, Siri Graff (2019). Effects of opioid receptor stimulation and blockade on touch pleasantness: a double-blind randomised trial. Social Cognitive & Affective Neuroscience. ISSN 1749-5016. doi: 10.1093/scan/nsz022. Full text in Research Archive
• Chelnokova, Olga V; Laeng, Bruno; Eikemo, Marie Helene; Riegels, Jeppe; Løseth, Guro & Maurud, Hedda [Show all 8 contributors for this article] (2014). Rewards of beauty: The opioid system mediates social motivation in humans. Molecular Psychiatry. ISSN 1359-4184. 19(7), p. 746–747. doi: 10.1038/mp.2014.1. Full text in Research Archive
• Chelnokova, Olga V; Laeng, Bruno; Riegels, Jeppe; Løseth, Guro Engvig; Eikemo, Marie Helene & Leknes, Siri Graff (2013). THE HUMAN OPIOID SYSTEM MEDIATES ATTENTION TO OTHERS' EYES. Journal of Cognitive Neuroscience. ISSN 0898-929X. p. 216–216. Full text in Research Archive

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