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Behavioural disorders: Overview


What is a behavioural disorder?

It is common for children and teens to get into trouble and be irritable or aggressive from time to time, especially during the toddler and early teen years. For instance, a young child may have a temper tantrum or a teenager may talk back or argue with you now and then.

Disordered behaviour is different from typical developmental behaviour because it happens more often than not and causes problems in more than one setting. For example, the behaviour not only affects school and home life but can make friendships and other peer relationships difficult.

There are two main types of behavioural disorder: oppositional defiant disorder and conduct disorder. Your child may have symptoms of one of these disorders​ if:

  • they have frequent outbursts, often at unexpected times (for example not just when tired or hungry)
  • have great difficulty following rules and expectations
  • their behaviour causes a lot of distress or trouble at home and school.

If you are concerned about your child or teen’s behaviour, consider if the frequency, duration and intensity of the behaviour are different than what would be expected for their particular developmental stage.

What causes behavioural disorders?

Behavioural disorders can be caused by:

  • biological factors
  • social and environmental factors
  • psychological factors.

Biological factors

Some traits seen in behavioural disorders can run in families. Children with a family history of behaviour problems, learning problems, anxiety, depression or bipolar disorder​ may be more likely to have a behaviour problem.

Social and environmental factors

Children who come from families that regularly experience a lot of stress may be more likely to show signs of a behavioural disorder. Some common family stressors might include:

  • financial difficulties
  • exposure to violence
  • family breakup
  • harsh or inconsistent parenting
  • inconsistent supervision, for example due to a parent’s mental health challenges or different styles of caregiving from a number of people.

Psychological factors

Children with behavioural disorders often have other mental health conditions (see below). How a child manages their emotions, activity level and attention may suggest vulnerability to certain behavioural disorders.

How common are behavioural disorders in children?

Behavioural disorders are common, occurring in 16 to 24 per cent of children and youth, from pre-schoolers through to teens.

When to seek help about your child’s behaviour

Consider speaking to a guidance counsellor or social worker in your child’s school about your child or teen’s behaviour if:

  • you notice sudden or unexpected behavioural changes (increased irritability or aggression with no known cause)
  • your child’s behaviour is more challenging than expected based on their developmental stage
  • your child’s behaviour continually prevents them from succeeding at school or maintaining positive relationships at home or in the community.

See a doctor if you would like to request a referral to a mental health professional such as an educational psychologist.

Do behavioural disorders occur with other conditions?

Other conditions that often occur along with behavioural disorders include:

Key points

  • Challenging behaviour becomes a concern when it is frequent and unexpected and leads to trouble at home, at school and with peers.
  • Behavioural disorders generally fall into two categories: oppositional defiant disorder and conduct disorder.
  • Behavioural disorders can be associated with a family history of challenging behaviour, family stresses and a poor ability to manage emotions and activity levels.
  • See your child’s doctor if your child’s behaviour changes suddenly or if their behaviour is more challenging than expected for their developmental stage.

Further information

For more information on behavioural disorders, please see the following pages:

Behavioural disorders: Signs and symptoms

Behavioural disorders: Treatment with psychotherapy and medications​

Behavioural disorders: How to help your child at home​​​

​Alice Charach, MD, MSc, FRCPC


Greene, R. (2014). The Explosive Child: A New Approach for Understanding and Parenting Easily Frustrated, Chronically Inflexible Children. Fifth edition. New York, NY: HarperCollins.

Phelan, T. (2014). 1-2-3 Magic: Effective Discipline for Children 2-12. Sixth edition. Naperville, IL: Sourcebooks, Inc.​