The term Peter Pan Syndrome has been accepted in popular psychology (i.e., is used by both laypeople and, informally, by some psychology professionals) since the publication of a book by this title (The Peter Pan Syndrome: Men Who Have Never Grown Up) written by Dr. Dan Kiley and published in 1983. (Kiley also wrote a companion book, The Wendy Dilemma, published in 1984.)

Many see this syndrome as very widespread in modern, post-industrial society.

The Peter-Pan psychological type is one characterized by immaturity or certain sorts of psychological problems. The type of male personality in question is immature and narcissistic. More completely, according to Kiley, the characteristics of a Peter-Pan man include such attributes as undependability, rebelliousness, anger, narcissism, dependency, and manipulativeness. According to Kiley, "Peter Pan" is the adult little boy who, when in a relationship or in seeking a relationship, acts out a need for mothering.

In his Peter Pan book, Kiley likened the characters of playwright J. M. Barrie's play, Peter Pan, to a dysfunctional co-dependent family.

"Wendy" is the adult little-girl role - a woman who (often unconsciously) acts in a mother role. Contributing the other half of co-dependent couple circumstance, her responses to the Peter-Pan man, according to Dr. Kiley, are such conduct s as overprotection, possessiveness, complaining, and "martyrdom".