Attention-deficit/hyperactivity disorder Features:

Inattention (six or more of the following in the last 6 months) careless mistakes in schoolwork or other activities Difficulty sustaining attention Often does not seem to listen when spoken to directly Difficulty organising tasks and activities Avoids, dislikes or reluctant to engage in tasks requiring sustained mental effort Often loses things necessary for tasks or activities Easily distracted by extraneous stimuli or unrelated thoughts Often forgetful in daily activities

Hyperactivity (six or more of the following in the last 6 months) Fidgets Leaves seat in situations when remaining seated is expected Runs about or climbs in inappropriate situations Unable to play or engage in leisure activities quietly Often “on the go” Often talks excessively Difficulty waiting for turn Often interrupts or intrudes on others

Prevalence: 5% of children and 2.5% of adults Usually first observed as a toddler, but symptoms difficult to distinguish from the norm

before 4 yrs old Most often identified in school aged children

Risk factors: Temperament Low birth weight 2-3x Heritability 2:1 male:female

Conduct disorder Features (3 of the following criteria in the past 12 months):

Aggression to people and animals Bullies, threatens or intimidates others Initiates physical fights Has used a weapon that can cause serious physical harm Physically cruel to people and/or animals Stolen while confronting a victim Forced someone into sexual activity

Destruction of property Arson Other deliberate methods of destruction

Deceitfulness or theft Broken into someone else’s house, building, car Often lies to obtain goods or favours Has stolen nontrivial items without confronting victim- shoplifting

Serious violations of rules Stays out at night Run away from home truancy

Subtypes: Childhood onset- male, physical aggression Adolescent onset- much less likely to display aggressive behaviours, male:female equal Unspecified onset

Prevalence: Around 4% May occur as early as preschool years, most during middle childhood through to middle

adolescence Oppositional defiance disorder is a common precursor

Risk factors: Temperament Parental rejection, neglect Physical/sexual abuse Lack of supervision Early institutional living Frequent change of caregivers Large family size Parent criminality Family history

Oppositional defiant disorder Features:

Angry/irritable mood Argumentative/defiant behaviour vindictiveness

Prevalence: 1-11% 4:1 male:female Usually onset in preschool years and often precedes conduct disorder Conveys risk of anxiety and major depressive disorder

Risk factors: Temperament Harsh, inconsistent or neglectful parenting

Intermittent explosive disorder

Features: Recurrent behavioural outbursts- verbal aggression, damage or destruction of property

and/or physical assault (animal or human) Magnitude of outburst grossly disproportionate to provocation Recurrent aggressive outbursts are not premeditated @ least 6 years old

Prevalence: Often associated with mood and anxiety disorders 2.7%, more prevalent among younger individuals Onset in late childhood or adolescence

Risk factors: Physical or emotional trauma in first 2 decades of life First-degree relatives

Intellectual disability (intellectual development disorder) Following 3 criteria:

Deficits in intellectual function (reasoning, problem solving etc) confirmed on clinical and standardised tests

Deficits in adaptive functioning which limits ADLs Onset of intellectual and adaptive deficits during developmental period

Severity based on social, conceptual, practical domains Prevalence

1% of population, varies with age Onset varies depending on aetiology and severity, from first 2 years of life to school age.

Risk factors Prenatal aetiology- genetic syndromes, brain malformations, maternal disease Perinatal causes- neonatal encephalopathy Post natal- hypoxia, TBI, infections, demyelinating disorders, seizure disorders, social

deprivation 1.2:1 male:female

Autism spectrum disorder

Persistent deficits in social communication and social interaction across multiple contexts: Deficits in social-emotional reciprocity Deficits in nonverbal communication Deficits in developing, maintaining and understanding relationships

Severity is based on social communication deficits and restricted, repetitive patterns of behaviour Features:

Stereotypy of movements Echolalia, idiosyncratic phrases Insistence on sameness, inflexible adherence to routines Ritualised patterns Highly restricted fixated interests with abnormal intensity/focus Hyper or hyporeactivity to sensory input or unusual interest in sensory aspect of

environment Risk factors:

Foetal exposure to valproate Heritability 4:1 male:female, though females more likely to have intellectual disabilities

Prevalence: 1% of population Symptoms typically from 2nd year of life Prognosis best if absence of intellectual disability and language impairment Epilepsy is an associated comorbidity