Defining Aggression


Anger is often an emotion, individuals experience in response to a real or perceived loss of a possession, space, self-esteem, value or sense of entitlement. Whilst, in the early stages of normal development an individual may react by being physically aggressive as a reaction. Most individuals outgrow this kind of behaviour as they emotionally mature and develop more sophisticated language and problem solving skills, individuals with persistent aggression or with a diagnosis of Conduct Disorder (CD) do not.

The Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-5) [American Psychiatric Publishing (APA), 2013], is a handbook that is used by professionals around the world to diagnose mental disorders. The DSM–5 describes CD as a persistent and long term (chronic) pattern of very problematic behaviour in which there are serious violations of social norms and rules. The behaviour problems are associated with physical aggression directed towards people and/or animals, destruction of property, deceitfulness, or theft and/or serious violation of rules. In other words the individuals frequently and persistently aggressive in situations where others of the same age would not respond aggressively. Unless it’s solved with Positive Behavior Support Strategies, this disturbance in behaviour causes clinically significant impairment in social, academic, or occupational functioning (APA, 2013).

DSM-5 (APA, 2013) describes the three subtypes of CD:

Childhood onset (i.e. the child showed at least one symptom characteristic of CD before the age of 10 years).

Adolescent onset (i.e. the child showed no symptom characteristic of CD before the age of 10 years).

Unspecified onset (i.e. unable to determine at what age the onset of the first symptom was).


There is no single cause, rather a number of risk factors that may contribute to the development of persistent aggression. They include::

Hereditary factors- Certain personality traits inherited from family members can make the child vulnerable.

Temperamental factors – The child has a difficult temperament or is aggressive from an early age that is difficult to manage.

Environmental factors –The influence of the family is a strong risk factor for many individuals. Some of the family level risk factors include:

  • Parental lack of supervision
  • Parental rejection and neglect
  • Parental discipline is too harsh or too relaxed or inconsistent
  • Parental inconsistent child rearing practices
  • Parental criminality
  • Parental disharmony
  • Lack of parental monitoring
  • Parents with a mental health problem
  • Parents with a substance abuse problems
  • Parents involved in criminal behaviour
  • Individual has been physically or sexually abused,
  • Individual living in institutionalised care
  • Individual has frequent changes of caregivers
  • Individual is part of a large family

Associated Emotional and Behavioural Difficulties

Emotional and behavioural difficulties may include some or all of the following:

Aggression towards people and animals

  • Often bullying, threatening, or intimidating others.
  • Often initiating physical fights.
  • Use weapons that can cause serious physical harm to others (e.g. a bat, brick, broken bottle, knife and guns).
  • Being physically cruel to people.
  • Being physically cruel to animals.
  • Stealing while confronting a victim (e.g., mugging, purse snatching, extortion, armed robbery).
  • Forcing others into sexual activity.

Destruction of property

  • Deliberately engaging in fire setting with the intention of causing serious damage.
  • Deliberately destroying others’ property (other than by fire setting).

Deceitfulness or theft

  • Breaking into someone else’s house, building, or car.
  • Often lying to obtain goods or favours or to avoid obligations (i.e. “cons” others).
  • Stealing items of non-trivial value without confronting a victim (e.g. shoplifting, but without breaking and entering; forgery).

Serious violations of rules

  • Often staying out at night despite parental prohibitions
  • Running away from home overnight at least twice while living in parental or parental surrogate home (or once without returning for a lengthy period).
  • Truancy from school

To learn how to support individuals or Students with Aggressive Behaviour or with a diagnosis of Conduct Disorder please refer to: Bhargava, D. (2018). Positive Behaviour Support Strategies for Students with Aggressive Behaviour: A Step by Step Guide to Assessing – Managing-Preventing Emotional and Behavioural Difficulties. Perth, WA: Behaviour Zen Pty Ltd.


American Psychiatric Association. (2013).  Diagnostic and Statistical Manual of Mental Disorders (5th Ed.).  Arlington, VA: American Psychiatric Publishing.