Biologically, an adult is a human or other organism that has reached sexual maturity. In human The time of puberty varies, but usually begins around 10 or 11 years old. Girls typically begin the process of puberty at age 10 or 11, and boys at.
Old age refers to ages nearing or surpassing the life expectancy of human beings , and is thus .. Another survey taken in 15 countries reported that mental disorders of adults interfered with their daily activities more than physical problems.
Gerontologist. 2002 Feb;42(1):92-9. A comparison of young, middle-aged, and older adult treatment-seeking pathological gamblers. Petry NM(1).
This is a great question. In my opinion, considering people as young adults, as a phase of development, would begin around 18 and definitely extend to 25+.