There are several individual causes of persistent aggressive or violent behaviour in children or adolescents.

Biological factors

Genetics contributes to a predisposition for aggressive behaviours even if environmental factors are excluded. Recent research demonstrates a multifactorial model with a couple of possible genes that may be involved. Studies of adopted children show an increased biological risk, but it is commonly accepted that genes plus environmental factors have the greatest influence on the later behaviour of children.

Wellknown biologically based syndromes with aggressive behaviours are:

• Conduct disorder (and/or ADHD or Oppositional Defiant Disorder) More information
• Bipolar (manic-depressive) disorder More information
• Use of drugs like alcohol, cocaine or speed More information
• Fetal alcohol syndrome (due to alcohol abuse of the mother)
• Tourette-Syndrome and related Tic-disorder More information
• Different types of seizure disorders
• Organic brain lesions (tumour, haematoma, cysts)