Juvenile/Delinquent theories Juvenile delinquency occurs when a minor participates and engages in illegal activity. There are several theories of juvenile delinquency that explain the causes behind delinquent and criminal behavior. These theories go into depth about why the delinquent is acting out or behaving in such an unpleasant way. The theories also discuss where the behavior stems from whether it’s family, social or psychological circumstances. The four main categories of juvenile delinquency theories include Biological, Anomie, Psychological, or Sociological. Examine both psychological and sociological theories and how it applies to delinquent behavior.