Nostalgia defined:  

“A sentimental longing or wistful affection for the past, typically for a period or place with happy personal associations.”  (Dictionary.com.)  Some Examples: The smell of honeysuckle during a childhood summer, a popular song during teenage years, a old photograph of a loved one — each invoking a reflection of prior happiness.

Research suggests that reflecting on happy memories may bring “surprising psychological benefits, from boosting self-confidence to buffering against anxiety and loneliness . . . by bringing into focus the people and experiences that have mattered most to us in the past.”  (Wallace, J. B. Nostalgia’s Power to Shape the Present, The Wall Street Journal, December 9, 2017, page C3)  

A Le Moyne University Professor of Psychology, Kristine Bacho, devised a questionnaire to measure “nostalgia” as a trait. The research concluded that those who value youthful memories scored higher, and “tend to value human relationships more and to be both more resilient and psychologically healthier.”  “The power of nostalgia lies not in just honoring the past but in bringing it forward to the present to make our lives richer and more meaningful: ‘it isn’t necessarily about wanting to go back’.” (id, quoting Dr Batcho)  

Isn’t that interesting?  Some well-known writers would agree, consider:

— “Sometimes you will never know the value of a moment until it becomes a memory.”  Dr. Seuss (1904—1991)

— “Isn’t it funny how day by day nothing changes but when you look back everything is different.”  C.S. Lewis (1898—1963)

But nostalgia has had its critics. Up until the turn of the millennium, psychologists concluded that the habit of living in memory; i.e., comparing the past to the present, may be a root cause of mental illness.  In 1688, Swiss physician Johannes Hofer coined the term “nostalgia” to define a mental illness in which people could fall into deep depression, like soldiers, who left home and became crippled by the sense of longing brought about by memories of home.  (Beck, Julie, The Atlantic Magazine, August 14, 2013.)

All in all, spending some pleasant moments with nostalgia may be beneficial for one’s overall health, provided one does not stay there too long.