Age

Adolescence[edit]

South Asian Female friends joyfully sharing Lunch

A study examined over 9,000 American adolescents to determine how their engagement in problem behavior (such as stealing, fighting, truancy) was related to their friendships. Findings indicated that adolescents were less likely to engage in problem behavior when their friends did well in school, participated in school activities, avoided drinking, and had good mental health. The opposite was found regarding adolescents who did engage in more problem behavior. Whether adolescents were influenced by their friends to engage in problem behavior depended on how much they were exposed to those friends, and whether they and their friendship groups "fit in" at school (Crosnoe, R., & Needham, B., 2004).^{[full citation needed]}

A study by researchers from Purdue University found that friendships formed during post-secondary education last longer than friendships formed earlier.^[14]

Adulthood[edit]

Friendships in adulthood

Life events such as marriage, parenthood, and accelerated career development can complicate friendships in the transition from young adulthood to middle adulthood. After marriage, both women and men report having fewer friends of the opposite sex (Friendships, 2012).^{[full citation needed]}

Adults may find it particularly difficult to maintain meaningful friendships in the workplace. "The workplace can crackle with competition, so people learn to hide vulnerabilities and quirks from colleagues. Work friendships often take on a transactional feel; it is difficult to say where networking ends and real friendship begins."^[15] Most adults value the financial security of their jobs more than friendship.^[16]

The majority of adults have an average of two close friends.^[17]

Old age[edit]

As family responsibilities and vocational pressures become less, friendships become more important.^[18] Among the elderly, friendships can provide links to the larger community; especially for people who cannot go out as often, interactions with friends allow for continued societal interaction. Additionally, older adults in declining health who remain in contact with friends show improved psychological well-being.

Although older adults prefer familiar and established relationships over new ones, friendship formation can continue in old age. With age, elders report that the friends to whom they feel closest are fewer in number and live in the same community. They tend to choose friends whose age, sex, race, ethnicity, and values are like their own. Compared with younger people, fewer older people report other-sex friendships. Older women, in particular, have more secondary friends—people who are not intimates, but with whom they spend time occasionally, such as in groups that meet for lunch or bridge.