2024
Efficacy and Safety of Ketamine/Esketamine in Bipolar Depression in a Clinical Setting.
Santucci M, Ansari M, Nikayin S, Radhakrishnan R, Rhee T, Wilkinson S. Efficacy and Safety of Ketamine/Esketamine in Bipolar Depression in a Clinical Setting. The Journal Of Clinical Psychiatry 2024, 85 PMID: 39361411, DOI: 10.4088/jcp.24m15376.Peer-Reviewed Original ResearchConceptsBipolar depressionAcute seriesRisk of affective switchDiagnosis of bipolar depressionRefractory bipolar depressionAcute phaseMADRS scoreAffective switchIntranasal esketamineManic episodesBipolar disorderCohort of patientsAttending psychiatristsSource of morbidityEsketamineSample of patientsIV ketamineMaintenance treatmentDepressionClinical responseHeightened riskClinical outcomesMania/hypomaniaKetamineKetamine/esketamineIn Vivo Synaptic Density in Early Schizophrenia: Are There No Differences or Are They Too Small to Detect?
Radhakrishnan R. In Vivo Synaptic Density in Early Schizophrenia: Are There No Differences or Are They Too Small to Detect? Biological Psychiatry 2024, 95: 605-607. PMID: 38479976, DOI: 10.1016/j.biopsych.2024.01.016.Peer-Reviewed Original ResearchConceptsSynaptic density
2023
Substance Use Disorder and Health Outcomes in COVID-19—The Need for a Better Research Method to Determine Substance Use Exposure
Christian N, Zhou X, Radhakrishnan R. Substance Use Disorder and Health Outcomes in COVID-19—The Need for a Better Research Method to Determine Substance Use Exposure. JAMA Psychiatry 2023, 80: 968-968. PMID: 37405794, DOI: 10.1001/jamapsychiatry.2023.2113.Peer-Reviewed Original ResearchImpact of personal beliefs about medical cannabis on physician recommendation practices: Results of an international survey
Syed S, Singh J, Elkholy H, Rojnić Palavra I, Tomicevic M, Eric A, Pinto da Costa M, Guloksuz S, Radhakrishnan R. Impact of personal beliefs about medical cannabis on physician recommendation practices: Results of an international survey. Asian Journal Of Psychiatry 2023, 85: 103634. PMID: 37257363, DOI: 10.1016/j.ajp.2023.103634.Peer-Reviewed Original ResearchRole of Psychedelics in Treatment-Resistant Depression
Kamal S, Jha M, Radhakrishnan R. Role of Psychedelics in Treatment-Resistant Depression. Psychiatric Clinics Of North America 2023, 46: 291-305. PMID: 37149346, DOI: 10.1016/j.psc.2023.02.004.Peer-Reviewed Original Research
2022
Age, gender and body-mass-index relationships with in vivo CB1 receptor availability in healthy humans measured with [11C]OMAR PET
Radhakrishnan R, Worhunsky PD, Zheng MQ, Najafzadeh S, Gallezot JD, Planeta B, Henry S, Nabulsi N, Ranganathan M, Skosnik PD, Pittman B, Cyril D'Souza D, Carson RE, Huang Y, Potenza MN, Matuskey D. Age, gender and body-mass-index relationships with in vivo CB1 receptor availability in healthy humans measured with [11C]OMAR PET. NeuroImage 2022, 264: 119674. PMID: 36243269, DOI: 10.1016/j.neuroimage.2022.119674.Peer-Reviewed Original ResearchBidirectional relationships between cannabis use, anxiety and depressive symptoms in the mediation of the association with psychotic experience: further support for an affective pathway to psychosis
Radhakrishnan R, Pries LK, Erzin G, Have M, de Graaf R, van Dorsselaer S, Gunther N, Bak M, Rutten BPF, van Os J, Guloksuz S. Bidirectional relationships between cannabis use, anxiety and depressive symptoms in the mediation of the association with psychotic experience: further support for an affective pathway to psychosis. Psychological Medicine 2022, 53: 5551-5557. PMID: 36093677, PMCID: PMC10482707, DOI: 10.1017/s0033291722002756.Peer-Reviewed Original ResearchConceptsAnxiety/depressive symptomsDepressive symptomsCannabis usePE incidencePsychotic experiencesFirst longitudinal cohort studyNetherlands Mental Health SurveyLongitudinal cohort studyMental Health SurveyRole of cannabisBidirectional relationshipCohort studyHealth SurveyIncidence studyAffective symptomsSymptomsCannabisEducation statusLongitudinal studyPsychosisIncidenceAnxietyTemporal relationshipMediation analysisFurther supportThe association between cannabis use and facial emotion recognition in schizophrenia, siblings, and healthy controls: Results from the EUGEI study
Fusar-Poli L, Pries LK, van Os J, Radhakrishnan R, Pençe AY, Erzin G, Delespaul P, Kenis G, Luykx JJ, Lin BD, Akdede B, Binbay T, Altınyazar V, Yalınçetin B, Gümüş-Akay G, Cihan B, Soygür H, Ulaş H, Cankurtaran EŞ, Kaymak SU, Mihaljevic MM, Andric-Petrovic S, Mirjanic T, Bernardo M, Mezquida G, Amoretti S, Bobes J, Saiz PA, García-Portilla MP, Sanjuan J, Aguilar EJ, Santos JL, Jiménez-López E, Arrojo M, Carracedo A, López G, González-Peñas J, Parellada M, Maric NP, Atbaşoğlu C, Üçok A, Alptekin K, Saka MC, investigators G, Aguglia E, Arango C, Rutten BP, Guloksuz S. The association between cannabis use and facial emotion recognition in schizophrenia, siblings, and healthy controls: Results from the EUGEI study. European Neuropsychopharmacology 2022, 63: 47-59. PMID: 36055075, DOI: 10.1016/j.euroneuro.2022.08.003.Peer-Reviewed Original ResearchConceptsHealthy controlsCannabis useDegraded Facial Affect Recognition TaskPresent cross-sectional studyCross-sectional studyHigh genetic riskProgression of schizophreniaRegular cannabis useCognitive disturbancesRegular cannabisPsychosis riskPatientsSchizophreniaFacial emotion recognition performanceGenetic riskCannabisCurrent cannabisEUGEI studyLongitudinal studyAgeSiblingsAssociationRiskOnsetEffect relationshipImpact of Cannabis Use, Substance Use Disorders, and Psychiatric Diagnoses on COVID-19 Outcomes: A Retrospective Cohort Study.
Ramakrishnan D, Sureshanand S, Pittman B, Radhakrishnan R. Impact of Cannabis Use, Substance Use Disorders, and Psychiatric Diagnoses on COVID-19 Outcomes: A Retrospective Cohort Study. The Journal Of Clinical Psychiatry 2022, 83 PMID: 36044600, DOI: 10.4088/jcp.21m14332.Peer-Reviewed Original ResearchConceptsCOVID-19 outcomesSubstance use disordersOpioid use disorderCOVID-19 patientsAlcohol use disorderRetrospective cohort studyVentilatory supportICU admissionUse disordersHospital admissionPsychiatric diagnosisCohort studyIntensive care unit admissionCOVID-19 positive patientsCare unit admissionLength of hospitalizationLarge health care systemMultivariable logistic regressionHigh-risk groupNumber of hospitalizationsBenzodiazepine use disorderCannabis use disorderUrine toxicology reportsElectronic medical recordsCocaine use disorder
2021
Dopamine D1R Receptor Stimulation as a Mechanistic Pro-cognitive Target for Schizophrenia
Abi-Dargham A, Javitch JA, Slifstein M, Anticevic A, Calkins ME, Cho YT, Fonteneau C, Gil R, Girgis R, Gur RE, Gur RC, Grinband J, Kantrowitz J, Kohler C, Krystal J, Murray J, Ranganathan M, Santamauro N, Van Snellenberg J, Tamayo Z, Wolf D, D’Souza D, Srihari V, Gueorguieva R, Patel P, Forselius-Bielen K, Lu J, Butler A, Fram G, Afriyie-Agyemang Y, Selloni A, Cadavid L, Gomez-Luna S, Gupta A, Radhakrishnan R, Rashid A, Aker R, Abrahim P, Nia A, Surti T, Kegeles L, Carlson M, Goldberg T, Gangwisch J, Benedict E, Govil P, Brazis S, Mayer M, de la Garrigue N, Fallon N, Baumvoll T, Abeykoon S, Perlman G, Bobchin K, Elliott M, Schmidt L, Rush S, Port A, Heffernan Z, Laney N, Kantor J, Hohing T, Gray D, Lieberman J. Dopamine D1R Receptor Stimulation as a Mechanistic Pro-cognitive Target for Schizophrenia. Schizophrenia Bulletin 2021, 48: 199-210. PMID: 34423843, PMCID: PMC8781338, DOI: 10.1093/schbul/sbab095.Peer-Reviewed Original ResearchConceptsCortical dopamine neurotransmissionPositive allosteric modulationImportant therapeutic targetPF-06412562Dopaminergic receptorsD1R stimulationDA levelsTolerable dosesLevel of stimulationDopamine neurotransmissionReceptor stimulationTherapeutic targetPartial agonistCognitive deficitsBiased agonismFull agonismTarget engagementAllosteric modulationNew drugsStimulationPoor bioavailabilitySchizophreniaOptimal stimulationDrugsExpression levelsIn vivo evidence of lower synaptic vesicle density in schizophrenia
Radhakrishnan R, Skosnik PD, Ranganathan M, Naganawa M, Toyonaga T, Finnema S, Hillmer AT, Esterlis I, Huang Y, Nabulsi N, Carson RE, D’Souza D. In vivo evidence of lower synaptic vesicle density in schizophrenia. Molecular Psychiatry 2021, 26: 7690-7698. PMID: 34135473, DOI: 10.1038/s41380-021-01184-0.Peer-Reviewed Original ResearchConceptsSynaptic vesicle densityHealthy controlsVesicle densityHigh-resolution research tomographySynaptic densitySCZ patientsVivo measuresNovel positron emission tomography (PET) ligandGender-matched healthy controlsCumulative antipsychotic exposurePositron emission tomography (PET) ligandSynaptic spine densityPsychosis symptom severityGray matter volumeJ bindingAntipsychotic exposureSpine densityDisease progressionFrontal cortexOccipital cortexTomography ligandTemporal cortexAnterior cingulateVivo findingsParietal cortex
2019
In vivo 5-HT6 and 5-HT2A receptor availability in antipsychotic treated schizophrenia patients vs. unmedicated healthy humans measured with [11C]GSK215083 PET
Radhakrishnan R, Matuskey D, Nabulsi N, Gaiser E, Gallezot JD, Henry S, Planeta B, Lin SF, Ropchan J, Huang Y, Carson RE, D'Souza DC. In vivo 5-HT6 and 5-HT2A receptor availability in antipsychotic treated schizophrenia patients vs. unmedicated healthy humans measured with [11C]GSK215083 PET. Psychiatry Research Neuroimaging 2019, 295: 111007. PMID: 31760336, DOI: 10.1016/j.pscychresns.2019.111007.Peer-Reviewed Original ResearchConceptsHealthy male controlsPositron emission tomographyMultilinear analysis 1Antipsychotic treatmentLower BPFrontal cortexReceptor availabilityAge-matched healthy male controlsDifferent second-generation antipsychoticsSteady-state troughPeak serum levelsSecond-generation antipsychoticsPotential therapeutic targetMale patientsSerum levelsHealthy humansTherapeutic targetSchizophrenia patientsTime-activity curvesMale controlsCognitive impairmentEmission tomographyVentral striatumPatientsSchizophrenia
2018
Efficacy and safety of a fatty acid amide hydrolase inhibitor (PF-04457845) in the treatment of cannabis withdrawal and dependence in men: a double-blind, placebo-controlled, parallel group, phase 2a single-site randomised controlled trial
D'Souza DC, Cortes-Briones J, Creatura G, Bluez G, Thurnauer H, Deaso E, Bielen K, Surti T, Radhakrishnan R, Gupta A, Gupta S, Cahill J, Sherif MA, Makriyannis A, Morgan PT, Ranganathan M, Skosnik PD. Efficacy and safety of a fatty acid amide hydrolase inhibitor (PF-04457845) in the treatment of cannabis withdrawal and dependence in men: a double-blind, placebo-controlled, parallel group, phase 2a single-site randomised controlled trial. The Lancet Psychiatry 2018, 6: 35-45. PMID: 30528676, DOI: 10.1016/s2215-0366(18)30427-9.Peer-Reviewed Original ResearchConceptsPF-04457845Cannabis withdrawal symptomsFatty acid amide hydrolaseCannabis withdrawalPlacebo groupAdverse eventsCannabis useWithdrawal symptomsFatty acid amide hydrolase inhibitorSerious adverse eventsPhase 2a trialWeeks of treatmentTreatment of cannabisCannabis use disorderSelf-reported cannabis useDSM-IV criteriaTreatment-related differencesTHC-COOH concentrationsAnandamide concentrationsTreat populationPrimary endpointPill countHospital admissionNovel FAAH inhibitorsSelf-reported cannabisInteraction between environmental and familial affective risk impacts psychosis admixture in states of affective dysregulation
Radhakrishnan R, Guloksuz S, Have M, de Graaf R, van Dorsselaer S, Gunther N, Rauschenberg C, Reininghaus U, Pries LK, Bak M, van Os J. Interaction between environmental and familial affective risk impacts psychosis admixture in states of affective dysregulation. Psychological Medicine 2018, 49: 1879-1889. PMID: 30284529, DOI: 10.1017/s0033291718002635.Peer-Reviewed Original Research
2015
GABA Deficits Enhance the Psychotomimetic Effects of Δ9-THC
Radhakrishnan R, Skosnik PD, Cortes-Briones J, Sewell RA, Carbuto M, Schnakenberg A, Cahill J, Bois F, Gunduz-Bruce H, Pittman B, Ranganathan M, D'Souza DC. GABA Deficits Enhance the Psychotomimetic Effects of Δ9-THC. Neuropsychopharmacology 2015, 40: 2047-2056. PMID: 25728472, PMCID: PMC4839528, DOI: 10.1038/npp.2015.58.Peer-Reviewed Original Research
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 daySmokersFeasibility, Safety, and Efficacy of the Combination of D-Serine and Computerized Cognitive Retraining in Schizophrenia: An International Collaborative Pilot Study
D'Souza DC, Radhakrishnan R, Perry E, Bhakta S, Singh NM, Yadav R, Abi-Saab D, Pittman B, Chaturvedi SK, Sharma MP, Bell M, Andrade C. Feasibility, Safety, and Efficacy of the Combination of D-Serine and Computerized Cognitive Retraining in Schizophrenia: An International Collaborative Pilot Study. Neuropsychopharmacology 2012, 38: 492-503. PMID: 23093223, PMCID: PMC3547200, DOI: 10.1038/npp.2012.208.Peer-Reviewed Original ResearchConceptsCognitive retrainingCognitive deficitsVerbal Working MemoryCognitive remediation strategiesAttention/vigilanceBasic information processingIndividual test performanceGlobal cognitive indexWorking memoryD-serineCognitive indicesCombination of pharmacotherapyTest performanceInformation processingMulticenter international clinical trialParallel group designSchizophrenia subjectsCollaborative pilot studyInternational clinical trialsUS samplePreliminary findingsCombination pharmacotherapySchizophreniaClinical trialsOutcome measures