Research suggests that combinations of psychosocial and biological factors are the most likely cause of conduct disorder (Kazdin, 1987; Patterson, Reid & Dishion, 1992).

Oregon Social Learning Centre researchers have examined the relationship between variables thought to cause conduct disorder and derived a model called the Vile Weed* (named after a plant that grows rampant in Oregon) that tracks the development of antisocial conduct.

Good news and bad news about the "Antisocial Trajectory"

Bad news: Truly is a VILE WEED. Once started, needs very little to keep growing. The longer it grows, the harder it is to get rid of.

Good news: Because it grows in predictable ways, and because the major roots lie in family interaction patterns, it is possible to combat it. In fact, there is no point at which it can't be addressed.

For more information about this model, the book Antisocial Boys (Patterson, Reid & Dishion, 1992) provides an excellent review.

*From a presentation by Phil Fisher, Oregon Social Learning Centre, at Youthorizons Auckland, 2005.