Cases of water intoxication without psychotic illness have been reported, including a case of massive water intake in the context of serious diarrhea [11], excess water supple-mentation for thirst during military training [12], compulsory water drinking as a form of child abuse [13] and massive water drinking during military urine drug screening [14]. Some of these cases demonstrated prolonged hyponatremia even at 20 h or more after the discontinuation of water intake, but the involvement of secondary SIADH was not discussed in the case reports. Hyponatremia resulting from water intoxication should be limited to the short term if the free water excretion is not disturbed. Therefore, the majority of the cases cited above may have been associated with secondary SIADH, as in the present case