Martin Ostenfeldt Trøstheim

• 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; Berey, Benjamin L.; Aston, Elizabeth R.; Gullo, Matthew J.; Hogarth, Lee & Simpson, Graham [Show all 9 contributors for this article] (2025). Assessing behavioural economic demand for morphine after an acute dose in individuals with- and without childhood trauma: a double-blind, randomised, controlled trial. Psychopharmacology. ISSN 0033-3158. doi: 10.1007/s00213-025-06977-7. Full text in Research Archive Show summary

  Abstract Background Childhood trauma is associated with positive subjective responses to acute opioids in the laboratory. Yet, its impact on behavioural economic demand for opioids remains unclear. Because demand can predict future use and misuse, we investigated whether individuals with childhood trauma also display greater demand for opioids in the laboratory. Methods This secondary analysis used data from a double-blind, randomised, controlled, counterbalanced trial. Across two sessions, individuals with ( n  = 26) and without ( n  = 21) childhood trauma received a high (0.15 mg/kg) and low (0.01 mg/kg) dose of intramuscular morphine 120 min before a hypothetical purchase task. Participants also regularly reported their subjective desire for the study drug. Area under the consumption and expenditure curves, and specific demand indices ( O max , P max , breakpoint , intensity , elasticity ), were analysed with non-parametric mixed models. Results Consumption and expenditure for low dose morphine was lower in the childhood trauma group when compared to high dose morphine in this group, and low dose morphine in the control group ( p s ≤ 0.03). Consistent results were obtained for specific demand indices O max , P max , and breakpoint , but not intensity or elasticity . Positive correlations between subjective desire and consumption and expenditure were only observed in the childhood trauma group ( Tau-c  = 0.24–0.34, p s ≤ 0.03). Conclusion Under laboratory conditions, desires to use opioids among individuals with childhood traumas may not manifest in strong intentions to acquire these drugs. Diverging results from psychometric measures of subjective and economic opioid value highlight the need for future research to explore contextual and resilience factors to understand how problematic opioid use emerges after childhood traumas.

• 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; Trøstheim, Martin Ostenfeldt & Leknes, Siri (2024). Endogenous mu-opioid modulation of social connection in humans: a systematic review and meta-analysis. Translational Psychiatry. 14(1). doi: 10.1038/s41398-024-03088-3. 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
• 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.

• 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.

• 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

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• Trøstheim, Martin Ostenfeldt (2026). Medications for Opioid Use Disorder and Their Implications for Patients’ Experiences of Pain and Reward. Universitetet i Oslo. Full text in Research Archive Show summary

  Opioid use disorder is a chronic relapsing condition that affects millions of people worldwide and that confers risk of major negative outcomes including overdose and death. Treatment of opioid use disorder often involves long-term use of medications that discourage harmful opioid use by either stimulating or blocking mu-opioid receptors. In this dissertation, the candidate reviews evidence for the proposed involvement of the mu-opioid system in human experiences of pain and reward and summarizes the current literature on these experiences in patients receiving medications for opioid use disorder. Novel direct comparisons of pain- and reward-related experiences between patients on opioid agonists and patients on extended-release naltrexone for opioid use disorder are presented based on observational data from a recent clinical trial. The findings of this dissertation indicate a state of reduced well-being in patients with opioid use disorder regardless of which medication they receive and highlight an unmet need for effective adjunct therapy.

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