RESUMEN
The N-methyl-D-aspartate receptor antagonist ketamine can improve major depressive disorder (MDD) within hours. To evaluate the putative role of glutamatergic and GABAergic systems in ketamine's antidepressant action, medial prefrontal cortical (mPFC) levels of glutamate+glutamine (Glx) and γ-aminobutyric acid (GABA) were measured before, during, and after ketamine administration using proton magnetic resonance spectroscopy. Ketamine (0.5 mg kg(-1) intravenously) was administered to 11 depressed patients with MDD. Glx and GABA mPFC responses were measured as ratios relative to unsuppressed voxel tissue water (W) successfully in 8/11 patients. Ten of 11 patients remitted (50% reduction in 24-item Hamilton Depression Rating Scale and total score ⩽10) within 230 min of commencing ketamine. mPFC Glx/W and GABA/W peaked at 37.8%±7.5% and 38.0%±9.1% above baseline in ~26 min. Mean areas under the curve for Glx/W (P=0.025) and GABA/W (P=0.005) increased and correlated (r=0.796; P=0.018). Clinical improvement correlated with 90-min norketamine concentration (df=6, r=-0.78, P=0.023), but no other measures.
Asunto(s)
Aminoácidos/metabolismo , Antidepresivos/uso terapéutico , Encéfalo/metabolismo , Trastorno Depresivo Mayor/tratamiento farmacológico , Ketamina/uso terapéutico , Neurotransmisores/metabolismo , Adulto , Antidepresivos/sangre , Encéfalo/efectos de los fármacos , Femenino , Ácido Glutámico/metabolismo , Glutamina/metabolismo , Humanos , Ketamina/sangre , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Proyectos Piloto , Espectroscopía de Protones por Resonancia Magnética , Escalas de Valoración Psiquiátrica , Tritio/metabolismo , Ácido gamma-Aminobutírico/metabolismoRESUMEN
A systematic observational procedure was used to obtain frequency counts of client and clinician initiated interchanges and clinician feedback during these interchanges. Repeated recordings were made of eight different speech pathologists interacting with two groups of four preschool children. Child responses to clinician initiated interchanges received significantly more positive feedback than child initiated verbalizations to the clinician. However, considerable variation among clinicians was found both in the frequency of spontaneous verbalizations by their clients and their reaction to this verbalization. Stepwise multiple regression analyses indicated that the type and amount of clinician feedback for client initiated verbalizations was significantly related to the frequency of these utterances to the clinician, but not to other children.