Developmental issues continue into adulthood, where the focus is on independence and adult relationships. In the young adulthood period, between 18 and 30 years of age, the individual struggles to achieve autonomy from parents, financial independence, and independent decision making. Peer pressure diminishes and the individual identity emerges. Health issues include following a healthy diet and exercise program, avoiding illicit drugs and alcohol, developing a healthy sexuality, and handling stress. Starting a family is a major adjustment for young adults. Pregnant women experience changes in self-concept and need to be assured that the changes they are going through are normal. Statistically, young adults are at risk of dying from accidents or suicide. They are also vulnerable to sexually transmitted diseases (STDs). Young adulthood is a critical time for nurses to teach breast and testicular self-examinations.

In middle adulthood (between 30 and 55 years), lifestyle, heredity, and environment make health promotion more challenging. Psychological stress and distress cause neuro-hormonal changes that negatively affect the autonomic nervous, immune, and endocrine systems. The most common conditions affecting morbidity and mortality at this time are cardiovascular disease, cancer, and obesity. Other health hazards are automobile accidents, often caused by alcohol, exposure to environmental toxins, and an unhealthy lifestyle. Physical stamina, muscle strength, and hearing diminish in middle age. Presbyopia, the inability of the visual lens to change shape, causes far-sightedness. The hair turns gray, menopause (the absence of the menses) and skin wrinkling begin, and calcium is lost from the bones, causing osteoporosis. People who do not follow their therapeutic regimens are nonadherent for a variety of reasons, such as not being able to afford treatment or not understanding the treatment instructions.

The primary developmental task of the middle-aged revolves around the conflict of generativity, a sense that one is making a contribution to society, versus stagnation, a sense of nonmeaning in one’s life. Accepting age-related changes is integral to processing this conflict. Resolving the conflict involves creativity, guiding the next generation, establishing lasting relationships, and evaluating goals in terms of achievement. People who have the personality characteristic of hardiness have the ability to withstand stress and tend to be healthier than those who are not hardy.