Spijkerman,R.van den Eijnden,R.J.J.M.van de Mheen,D.Bongers,I.M.B.Fekkes,D.2025-02-012025-02-012002Spijkerman, R, van den Eijnden, R J J M, van de Mheen, D, Bongers, I M B & Fekkes, D 2002, 'The impact of smoking and drinking on plasma levels of norharman', European Neuropsychopharmacology, vol. 12, no. 1, pp. 61-71. https://doi.org/10.1016/S0924-977X(01)00143-20924-977Xarno: 89393metis: 237507ORCID: /0000-0002-2885-3537/work/16086476110.1016/S0924-977X(01)00143-2https://hdl.handle.net/20.500.14602/39056The hypothesized role of the beta-carboline norharman in processes of drug dependence forms the basis for several studies on plasma levels of norharman among substance-using populations, particularly among alcoholics and smokers. However, it is not clear whether norharman is implicated in processes of dependence to both substances, or only to tobacco smoke. In the present study plasma concentrations of norharman were measured among four groups of participants regarding heavy smokers who do or do not drink alcohol excessively and nonsmokers who do or do not drink alcohol excessively. All measurements were conducted on three different days with an interval of 2 months in between and at three times during the day to account for possible circadian or seasonal variations. Results showed that elevated plasma levels of norharman appear only in heavy smokers regardless of their drinking profile. The norharman plasma levels of nonsmoking excessive drinkers showed a similar pattern to that of the control group. The findings indicate that elevated plasma levels of norharman are due to heavy smoking and not to excessive drinking.enginfo:eu-repo/semantics/closedAccessSDG 3 - Good Health and Well-beingArticleGeneral rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. - Users may download and print one copy of any publication from the public portal for the purpose of private study or research. - You may not further distribute the material or use it for any profit-making activity or commercial gain - You may freely distribute the URL identifying the publication in the public portal" Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.474743https://research.tilburguniversity.edu/en/publications/c71b8bc3-8310-4b79-a68b-973de98ebcbe(c) Universiteit van TilburgSpijkerman, R.van den Eijnden, R.J.J.M.van de Mheen, D.§0000-0002-7918-1523Bongers, I.M.B.§0000-0002-2885-3537Fekkes, D.