Abstract
Objectives: Epidemiological and experimental evidence suggests that the endocannabinoid system plays a pathophysiological role in schizophrenia. This is reflected by elevated cerebrospinal levels of the endocannabinoid anandamide in schizophrenia and its initial prodromal states.
Methods: We analyzed plasma concentrations of anandamide, 2-arachidonoyl-sn-glycerol, palmitoylethanolamide and oleoylethanolamide from 25 twin pairs discordant for schizophrenia, six discordant for bipolar disorder and eight healthy twin pairs to determine hereditary traits.
Results: Twin pairs discordant for schizophrenia or bipolar disorder had significantly higher levels of anandamide and palmitoylethanolamide compared to healthy twins (both P < 0.002). Non-affected twins discordant for schizophrenia, who developed a psychotic disorder within 5 years follow-up showed lower anandamide (P = 0.042) and 2-arachidonoyl-sn-glycerol levels (P = 0.049) than twins who remained healthy.
Conclusions: We suggest that the protective upregulation of endocannabinoid signalling reflects either a hereditary trait or mirrors a modulating response to genetically influenced cerebral function involving, e.g., other neurotransmitters or energy metabolism.
Acknowledgements
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Statement of interest
All authors declare that they have no conflicts of interest. AML discloses speaker and/or advisor or authorship fees from Astra Zeneca, Servier, Bristol-Myers Squibb GmbH & Co.KGaA, Desitin Arzneimittel GmbH, Defined Health, F. Hoffmann-La Roche Ltd., Lilly Deutschland GmbH, Gerson Lehrmann Group (GLG), Pricespective, Elsevier, Alexza Pharmaceuticals Inc., Outcome Sciences Inc., Pfizer Pharma GmbH, Janssen-Cilag EMEA. FML discloses speaker and/or advisor or authorship fees from Astra Zeneca, Bristol-Myers Squibb GmbH & Co. KGaA, Essex Pharma GmbH, Exafield, Future Science Group, Lilly Research Laboratories, Lundbeck GmbH, Medical Tribune, Neuro Depesche. He is a shareholder of Curantis UG (Ltd.). All other authors have nothing to declare.