Pharmaceutical compositions containing 5-methyltetrahydrofolic acid, 5-formyltetrahydrofolic acid and their pharmaceutically acceptable salts in controlled-release form active in the therapy of organic mental disturbances

In a therapeutic method for treating an elderly depressed patient diagnosed as having at least one organic mental disturbance selected from the group consisting of senile primary degenerative dementia of the Alzheimer type with depression, presenile primary degenerative dementia of the Alzheimer type with depression, and multiinfarctual dementia with depression, the improvement, as compared to orally administering folate not in controlled-release form, or to placebo, consisting essentially of the step of orally administering a therapeutically effective amount of 5-methyl-tetrahydrofolic acid or 5-formyl-tetrahydrofolic acid or a pharmaceutically acceptable salt thereof in a controlled-release form.