Juvenile elinquency refers to criminal acts performed by juveniles. Most legal systems prescribe specific procedures for dealing with juveniles, such as juvenile detention centers. There are a multitude of different theories on the causes of crime, most if not all of which can be applied to the causes of youth crime. Youth crime is an aspect of crime which receives great attention from the news media and politicians. Crime committed by young people has risen since the mid-twentieth century, as have most types of crime. The level and types of youth crime can be used by commentators as an indicator of the general state of morality and law and order in a country, and consequently youth crime can be the source of ‘moral panics’ Theories on the causes of youth crime can be viewed as particularly important within criminology. This is firstly because crime is committed disproportionately by those aged between fifteen and twenty-five. Secondly, by definition any theories on the causes of crime will focus on youth crime, as adult criminals will have likely started offending when they were young. A Juvenile Delinquent is one who repeatedly commits crime, however these juvenile delinquents could most likely have mental disorders/behavioral issues such as schizophrenia, post traumatic stress disorder or bipolar disorder. It has been stipulated that the term 'Juvenile Delinquent' is actually a contradiction in terms. This idea is used early on in Robert Heinlein's science fiction novel Starship Troopers.