2022
Associations Between Cannabis Use, Polygenic Liability for Schizophrenia, and Cannabis-related Experiences in a Sample of Cannabis Users
Johnson E, Colbert S, Jeffries P, Tillman R, Bigdeli T, Karcher N, Chan G, Kuperman S, Meyers J, Nurnberger J, Plawecki M, Degenhardt L, Martin N, Kamarajan C, Schuckit M, Murray R, Dick D, Edenberg H, D’Souza D, Di Forti M, Porjesz B, Nelson E, Agrawal A. Associations Between Cannabis Use, Polygenic Liability for Schizophrenia, and Cannabis-related Experiences in a Sample of Cannabis Users. Schizophrenia Bulletin 2022, 49: 778-787. PMID: 36545904, PMCID: PMC10154717, DOI: 10.1093/schbul/sbac196.Peer-Reviewed Original ResearchConceptsCannabis useAlcohol use disorderCognitive difficultiesSchizophrenia polygenic risk scoresFirst cannabis useDaily cannabis useCannabis usersSocial withdrawalUnusual experiencesCannabis involvementPolygenic risk scoresExpected directionGenetic riskUse disordersIndependent replication sampleLike experiencesGenetic liabilityCannabisSchizophreniaPolygenic riskPolygenic liabilityReplication sampleExperienceAnalytic sampleDisorders
2019
Characterizing psychosis-relevant phenomena and cognitive function in a unique population with isolated, chronic and very heavy cannabis exposure
D'Souza DC, Ganesh S, Cortes-Briones J, Campbell MH, Emmanuel MK. Characterizing psychosis-relevant phenomena and cognitive function in a unique population with isolated, chronic and very heavy cannabis exposure. Psychological Medicine 2019, 50: 2452-2459. PMID: 31615592, DOI: 10.1017/s0033291719002721.Peer-Reviewed Original ResearchConceptsSchizotypal Personality QuestionnaireCognitive performanceCannabis exposureTests of attentionComputerized cognitive batteryVisuo-spatial processingHigher SPQ scoresSubstance use/misuseWorse cognitive performanceHeavy cannabis exposureLarge effect sizesUse/misuseCognitive flexibilityVerbal memoryCognitive batteryCognitive functioningPsychomotor speedSPQ scoresCognitive functionCognitive deficitsCannabis usersPersonality QuestionnaireCannabis useUse of cannabisEarly cannabisGrey Matter Volume Differences Associated with Extremely Low Levels of Cannabis Use in Adolescence
Orr C, Spechler P, Cao Z, Albaugh M, Chaarani B, Mackey S, D'Souza D, Allgaier N, Banaschewski T, Bokde ALW, Bromberg U, Büchel C, Quinlan E, Conrod P, Desrivières S, Flor H, Frouin V, Gowland P, Heinz A, Ittermann B, Martinot JL, Martinot MP, Nees F, Orfanos D, Paus T, Poustka L, Millenet S, Fröhner JH, Radhakrishnan R, Smolka MN, Walter H, Whelan R, Schumann G, Potter A, Garavan H. Grey Matter Volume Differences Associated with Extremely Low Levels of Cannabis Use in Adolescence. Journal Of Neuroscience 2019, 39: 1817-1827. PMID: 30643026, PMCID: PMC6407302, DOI: 10.1523/jneurosci.3375-17.2018.Peer-Reviewed Original ResearchConceptsGray matter volumeCannabis useCannabis usersPerceptual Reasoning IndexGreater gray matter volumeMedial temporal lobeBilateral posterior cingulateGeneralized anxiety symptomsBilateral medial temporal lobesInitiation of cannabisRates of cannabisLong-term neurocognitive effectsGray matter volume differencesCognitive effectsHuman adolescentsNeurocognitive effectsAnxiety symptomsVoxel-based morphometryLingual gyrusPosterior cingulateRecreational cannabis useAdolescent periodTemporal regionsHeavy patternNeural maturation
2012
Acute effects of THC on time perception in frequent and infrequent cannabis users
Sewell RA, Schnakenberg A, Elander J, Radhakrishnan R, Williams A, Skosnik PD, Pittman B, Ranganathan M, D’Souza D. Acute effects of THC on time perception in frequent and infrequent cannabis users. Psychopharmacology 2012, 226: 401-413. PMID: 23179965, PMCID: PMC3581701, DOI: 10.1007/s00213-012-2915-6.Peer-Reviewed Original ResearchConceptsCannabis smokersAcute effectsFrequent cannabis smokersPlacebo-controlled studyCannabis usersChronic cannabis smokersInfrequent cannabis usersWhole-plant cannabisChronic cannabis useResultsAll dosesVariable pharmacokineticsBlunted responseSubjects three timesHigh dosesTHC effectsFrequent cannabis usersCannabis useInternal clock speedΔ9-tetrahydrocannabinolSmall sample sizeDosesFrequent cannabisThree timesTest daySmokersThe Effect of Chronic Cannabinoids on Broadband EEG Neural Oscillations in Humans
Skosnik PD, D'Souza DC, Steinmetz AB, Edwards CR, Vollmer JM, Hetrick WP, O'Donnell BF. The Effect of Chronic Cannabinoids on Broadband EEG Neural Oscillations in Humans. Neuropsychopharmacology 2012, 37: 2184-2193. PMID: 22713908, PMCID: PMC3422484, DOI: 10.1038/npp.2012.65.Peer-Reviewed Original ResearchConceptsNeural oscillationsAuditory steady-state responseCannabis usersCannabis groupGamma rangeChronic cannabis usersCentral cannabinoid-1 receptorsCognitive processesTransient ERPsChronic cannabisChronic cannabinoidsHz powerEEG dataCurrent studyEffects of cannabinoidsCannabisPsychopharmacological effectsExogenous cannabinoidsNaïve controlsElectroencephalographySpectral powerTrial powerEarly ageX frequencyERPDose-Related Modulation of Event-Related Potentials to Novel and Target Stimuli by Intravenous Δ9-THC in Humans
D'Souza DC, Fridberg DJ, Skosnik PD, Williams A, Roach B, Singh N, Carbuto M, Elander J, Schnakenberg A, Pittman B, Sewell RA, Ranganathan M, Mathalon D. Dose-Related Modulation of Event-Related Potentials to Novel and Target Stimuli by Intravenous Δ9-THC in Humans. Neuropsychopharmacology 2012, 37: 1632-1646. PMID: 22334121, PMCID: PMC3358754, DOI: 10.1038/npp.2012.8.Peer-Reviewed Original ResearchConceptsRecent cannabis usersPerceptual alterationsERP componentsCannabis usersEvent-related potential taskSensory ERP componentsCannabis Use StatusModulation of eventsΔ9-THCProperties of cannabisContext updatingNeural correlatesP3b amplitudeTarget stimuliPsychophysiological indicesCortical processesP300b amplitudesProcessing speedCognitive deficitsPsychophysiological dataInformation processingAutomatic orientationCounterbalanced designSubjective effectsPotential tasks
2009
Cannabinoids and psychosis
Sewell RA, Ranganathan M, D'Souza DC. Cannabinoids and psychosis. International Review Of Psychiatry 2009, 21: 152-162. PMID: 19367509, DOI: 10.1080/09540260902782802.Peer-Reviewed Original ResearchConceptsGeneral populationPsychotic disordersTrigger relapseCannabis usersCognitive symptomsCross-sectional studyIndividual vulnerabilityCannabis useCannabinoid receptor functionLongitudinal studyCase seriesPsychotic illnessPsychotic symptomsCannabisHealthy individualsSchizophreniaPharmacological studiesReceptor functionAutobiographical accountsPsychosisEarly exposureSymptomsTwo-fold increaseConsiderable evidenceComponent causes