... Human life is divided into four ages. The first is called adolescence, that is, the "increasing" of life. The second is called "manhood," that is to say, the age of achievement, which may give perfection . . . The third is called old age. The fourth is called decrepitude. . . .
As to the first, no one hesitates, but every sage agrees that it lasts up to the twenty-fifth year; and because up to that time our soul is chiefly intent on conferring growth and beauty on the body, whence many and great changes take place in the person, and rational part cannot come to perfect discretion; wherefore Reason lays down that before this age there are certain things a man may not do without a guardian of full age. (Dante: Convivio, IV, 24.)
In this paper we should like to report the clinical course of 3 adolescent girls who presented a complex diagnostic picture
COHEN RE, LESTER G. Limit Setting as a Corrective Ego Experience. Arch Gen Psychiatry. 1963;8(1):74–79. doi:10.1001/archpsyc.1963.01720070076009