A PKB (Akt) activating agent comprising a compound represented by the formula (I): wherein R1 and R2: H, a hydrocarbon group or a heterocyclic group or R1 and R2 form a ring in cooperation with the adjacent carbon atom; R3: H, a hydrocarbon group or a heterocyclic group; W: represents a group represented by the formulas: wherein ring A: an optionally substituted benzene ring; ring B: an optionally substituted 5- to 7-membered nitrogen-containing heterocycle; R4: an aliphatic hydrocarbon group substituted with an aromatic group and further optionally substituted, or an acyl group containing an aromatic group; R5: H, C1-6 alkyl or acyl; R4c: an aromatic group, an aliphatic hydrocarbon group or acyl; and X: O or S; Y: O, S or NH; and ring C: an optionally substituted benzene ring, or a salt or a prodrug thereof, and use of the activating agent in prevention or treatment of depression, anxiety, manic-depressive psychosis or PTSD are provided.