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/esketamine
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 Research
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 levels
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