We found (1) a decrease in GABA sensitivity in Dravet syndrome compared to controls, which was related to an increase in α4- relative to α1-containing GABA<sub>A</sub> receptors; (2) a shift of the GABA reversal potential toward more depolarizing values in Dravet syndrome, and a parallel increase of the chloride transporters NKCC1/KCC2 expression ratio; (3) an increase of GABA<sub>A</sub> currents induced by low doses of cannabidiol both in Dravet syndrome and tuberous sclerosis complex comparable to that induced by a classical benzodiazepine, flunitrazepam, that still persists in γ-less GABA<sub>A</sub> receptors.