Autism and disruptive behavioural disorders

• Autism spectrum disorder (ASD) is a neurodevelopmental condition in which a person has persistent difficulty with social communication and restricted or repetitive patterns of behaviour, interest or activity, usually evident in early childhood.
• It is a spectrum: the same diagnosis covers very different levels of language, learning and daily-life support, and co-occurring conditions are common.
• Children referred with possible autism need a structured specialist assessment based on ICD-11 or DSM-5-TR criteria, not a single questionnaire; hearing and vision checks matter.
• There is no medicine for the core features of autism, but structured behavioural, developmental and educational interventions improve skills; risperidone or aripiprazole are licensed in several countries for irritability associated with autistic disorder.
• Oppositional defiant disorder and conduct disorder are disruptive behaviour disorders driven by development, context and learning; parent management training is the first-line psychosocial intervention for children, risperidone is considered only for short-term severe aggression that has not responded to psychosocial work. ^[3]
• Intermittent explosive disorder and later antisocial personality disorder share antecedents of impulsive aggression and childhood conduct problems, but they differ in age of onset, pattern and whether there is calculated harm.

By the end of this page you should be able to:

1. Recognise the two DSM-5-TR domains of ASD and the way they interact with development and co-occurring conditions.
2. Plan screening and referral for a child or young person with possible autism, including what can and cannot be ruled in or out at each step.
3. Outline the components of a specialist autism diagnostic assessment and the tests used alongside it.
4. Describe evidence-based supports and interventions for ASD and when pharmacological treatment is justified.
5. Distinguish oppositional defiant disorder, conduct disorder, intermittent explosive disorder and antisocial personality disorder by onset, behaviour and prognosis.
6. Design or select a parent management training programme and state its structure, dose and expected monitoring from NICE CG158.
7. Communicate risk, prognosis and low-resource options to families.

Two practical points follow. First, DSM-5-TR collapsed older subtypes such as autistic disorder and Asperger syndrome into one spectrum; the single label is "autism spectrum disorder". Second, severity is described by the level of support a person needs in daily life, so one diagnosis covers a wide range of outcomes. The acronym ASD is used throughout this page for autism spectrum disorder.

Disruptive behavioural disorders are conditions in which behaviour persistently violates social norms or harms others. The group covered here has four members:

• Oppositional defiant disorder (ODD): a pattern of angry, argumentative, defiant and sometimes vindictive behaviour, directed mainly at authority figures and impairing relationships.
• Conduct disorder (CD): a repetitive and persistent pattern of behaviour in which the rights of others or major age-appropriate social norms are violated, including aggression to people and animals, destruction of property, deceitfulness or theft and serious rule violations.
• Intermittent explosive disorder (IED): repeated bursts of anger or aggression that the person cannot restrain and that are far larger than the trigger warrants.
• Antisocial personality disorder (ASPD): a pervasive pattern of disregard for and violation of the rights of others, which by definition emerges in adulthood; the link with childhood conduct problems is discussed below.

Classification therefore separates conditions by age, context and intent rather than by a single score. Many children have more than one label, and autism itself can be misread as a disruptive behaviour disorder when communication difficulties are misunderstood.

ASD is common and is identified in every racial, ethnic and socioeconomic group.^[7] CDC surveillance in the United States found that about 1 in 31 (3.2%) children aged 8 years has been identified with ASD, up from about 1 in 150 in 2000.^[7] ASD is over three times more common among boys than among girls.^[7] About 1 in 6 (17%) children aged 3 to 17 years has been diagnosed with at least one developmental disability.^[7] Prevalence figures have risen over successive surveillance years, reflecting broader ascertainment, wider public awareness and changing diagnostic practice as well as any true change in incidence.^[7]

One recent global estimate put the number of autistic people at about 61.8 million in 2021 (about 788 per 100,000), with higher identified rates in males than in females.^[9] Worldwide estimates still vary because case-finding methods differ; use local surveillance as well. Girls and women are under-recognised, which means their true prevalence is higher than identified prevalence.^[2]

For disruptive behaviour disorders, no single global figure is quoted here. The conditions sit on a continuum from normative defiance in early childhood to persistent conduct problems. ODD in particular is common in preschool and early school years and often settles; conduct disorder is less common and carries a heavier burden. Intermittent explosive disorder occurs in a minority of people with serious aggression problems. Antisocial personality disorder is an adult diagnosis that develops only in a small subset of those with childhood conduct disorder.

ASD is multifactorial. There is a strong genetic contribution, reflected in high heritability and recurrence within families, but no single gene explains most cases. Identifiable genetic conditions and chromosomal disorders increase the likelihood (for example, fragile X syndrome, Down syndrome, tuberous sclerosis, neurofibromatosis).^[2] Medical risk factors include gestational age under 35 weeks, severe neonatal encephalopathy, major brain malformation and coexisting intellectual disability.^[2] Psychiatric risk factors include ADHD, which is frequently co-occurring and under-recognised when autism is diagnosed first.^[2]

Pregnancy-specific factors matter for counselling. A sibling with autism, maternal use of valproate or topiramate in pregnancy, and paternal valproate use in the three months before conception are associated with increased prevalence.^[2] Hearing and vision impairment, cerebral palsy and severe motor disorders can mask or confuse the picture.^[2]

Risk for ODD, CD and IED includes early adversity (abuse, domestic violence, insecure attachment), harsh or inconsistent discipline, poor supervision, low family income, parental substance misuse, criminality or mental illness, peer rejection, academic failure and co-occurring ADHD.^[3] ODD is best understood as an interaction between a child's temperament and a parenting environment that has drifted into coercive cycles; this is why parent management training is the core treatment rather than a punishment-based approach.^[3]

Antisocial personality disorder emerges when childhood conduct problems, especially those beginning in early childhood with callous-unemotional traits, persist into adulthood in the context of continuing adversity. Only some children with conduct disorder go on to develop ASPD; many desist.^[3]

Autism is a brain-based, early-appearing difference in development rather than a degenerative disease. The current picture is of multifactorial influences on early brain development leading to atypical neural connectivity, sensory processing and the social-communication circuitry that supports joint attention, reciprocity and flexible behaviour.^[6] Co-occurring intellectual disability, epilepsy, ADHD and anxiety are common, which tells you that the same biological influences affect several developmental systems at once. No single biological marker is used to diagnose ASD in routine practice.^[2]

For disruptive behaviour disorders, the key mechanisms are behavioural rather than structural: difficult temperament and attention problems in a child combine with inconsistent or coercive parenting and with academic or social failure, producing reinforcement of antisocial behaviour. Poor executive control, hostile attribution bias and reduced empathy amplify the cycle. The brain is not "broken"; patterns become entrenched through learning and context, which is also why they can be unlearned with structured intervention.^[3]

Presentation is heterogeneous, but most people show difficulties in two areas.

Social communication and interaction may include reduced eye contact, limited shared enjoyment, delayed or unusual language, difficulty reading faces and tone, difficulty sustaining conversation, reduced pretend play and difficulty making or keeping friends.^[6] CDC surveillance pages list delays recognised in the first one to two years, such as not responding to name by 9 months or not pointing by 18 months.^[6]

Restricted and repetitive behaviour and interests include lining up objects, repeating phrases, insisting on sameness, narrow and intense interests, repetitive motor movements and unusual sensory responses.^[6] Other common associated features are delayed motor and cognitive skills, hyperactivity and inattention, epilepsy, sleep and feeding problems, gastrointestinal problems and anxiety.^[6]

Girls and women more often camouflage social difficulty and present with internalising symptoms or eating difficulties, so ask specifically and do not rely on obvious stereotyped behaviour.^[2]

Examination. A developmental and behavioural assessment, a full general physical examination, and a mental-state assessment are part of the pathway. Look for skin stigmata of neurofibromatosis or tuberous sclerosis, dysmorphic features, congenital anomalies, macrocephaly or microcephaly, self-injury and marks of any maltreatment.^[2] Developmental level, language, adaptive behaviour, sensory profile, physical health and nutrition all belong in the assessment.^[2] Hearing and vision must be checked before conclusions are drawn.^[2]

In ODD the child argues with adults, loses temper, defies or refuses requests, deliberately annoys others, blames others for mistakes and shows spiteful or vindictive behaviour, for months rather than days.^[3] In conduct disorder the behaviours are more serious: aggression to people and animals, destruction of property, deceitfulness or theft and serious rule violations.^[3] NICE suggests that negativistic, hostile or defiant behaviour patterns are expected under about 11 years, with aggression to people and animals, property destruction, deceit or theft and serious rule violations more typical over 11 years, but both can occur at any age.^[3] Significant complicating factors (depression, PTSD, ADHD, autism, learning disability, substance misuse) should trigger a comprehensive specialist assessment.^[3]

Intermittent explosive disorder presents with discrete episodes of impulsive aggression that are disproportionate to the trigger, followed by relief and later distress or embarrassment. It must be separated from calculated, instrumental aggression; from aggression in autism driven by overload or communication difficulty; from psychosis; from substance intoxication; and from personality pathology. The typical patient is a young adult whose anger is impulsive rather than premeditated.^[3]

Red flags for serious harm. Self-injury, suicidal ideation, harm to animals, weapons or fire-setting, sexual boundary violations, severe family conflict and suspected abuse or neglect all require safeguarding action under local protocols.^[3]

The diagnosis of autism is clinical and syndromic. No blood test, brain scan or questionnaire makes or rules out the diagnosis on its own.^[1][2]

Systemic conditions such as ADHD, intellectual disability, language disorder, anxiety, depression, OCD, conduct disorder, attachment disorder and PTSD must be considered as coexisting or alternative explanations.^[2] Sensory impairments can look like social impairment and should be excluded or accounted for.^[2]

DSM-5-TR criteria are copyrighted, so this remains a summary of their structure rather than a quotation. The structure below is taken from an open review's account of DSM-5-TR.^[9] There are two required symptom domains, with onset in the early developmental period and impairment in functioning.

1. Social communication and social interaction (all three features must be present, currently or by history): ^[9]
   • reduced social-emotional reciprocity
   • reduced non-verbal communicative behaviour used for social interaction
   • impaired ability to develop, maintain and understand relationships.
2. Restricted, repetitive patterns of behaviour, interests or activities (two or more of four):
   • stereotyped or repetitive motor movements, use of objects or speech
   • insistence on sameness, inflexible routines or ritualised behaviour
   • highly restricted, fixated interests that are abnormal in intensity or focus
   • hyper- or hypo-reactivity to sensory input or unusual interest in sensory aspects of the environment.
3. Symptoms are present in the early developmental period, typically recognised in the first two years of life, although they may not become fully manifest until social demands exceed capacity or may be masked by learned strategies later. ^[9]
4. Symptoms cause clinically significant impairment in social, occupational or other important areas of functioning.
5. They are not better explained by intellectual disability or global developmental delay alone. ^[9]

In practice, the requirement that all three social-communication features be present helps avoid over-diagnosis, while the "two or more" rule for repetitive features preserves the breadth of the spectrum. Severity is then described by support needs. Co-occurring intellectual disability, language disorder, ADHD or another neurodevelopmental or mental disorder can be coded separately and changes the management plan.^[2][9]

Recognition should start at first concern rather than at final diagnosis. Parents and carers, and children and young people who can, should have their concerns taken seriously even when others do not share them.^[2] Possible autism can be under-recognised in girls, in verbally able children, in children with intellectual disability, and in children whose early signs were masked by coping or a supportive environment; it can be missed after an earlier assessment concluded "no autism" if new information becomes available.^[2] Conversations about possible autism need to be sensitive, because raising it can cause distress when no one has suspected it.^[2]

NICE CG128 sets out a structured local pathway: a multi-agency strategy group, an autism team with paediatric or child-psychiatry, speech and language therapy and psychology input, and a single point of referral.^[2] Referral points are specific: children under 3 years with regression in language or social skills; children older than 3 years with language regression; any age with motor regression, which should first go to paediatrics or paediatric neurology.^[2] After referral, a case coordinator organises the assessment, and the diagnostic assessment should start within 3 months.^[2] Every diagnostic assessment must include a developmental history, direct observation of social and communication skills, a medical history, a physical examination and a considered differential and coexisting-condition screen.^[2]

Diagnostic uncertainty is normal in children under 24 months, in children with developmental age under 18 months, in children with complex coexisting conditions and in children whose early-life information is unavailable.^[2] In those situations the right response is time, repeated observation in more than one setting and sometimes a second opinion, not a label forced too early.^[2] Assessment findings should be communicated in person and without delay, in writing, with a follow-up appointment within 6 weeks.^[2]

No medication treats the core symptoms of autism.^[8] Current treatments aim to reduce symptoms that interfere with daily functioning and quality of life, delivered across education, health, community and home settings.^[8] Evidence for benefit is strongest for behavioural approaches, particularly applied behaviour analysis (ABA) and naturalistic developmental behavioural interventions, and for developmental therapies for language and daily living skills.^[8]

Non-pharmacological supports include:

• Behavioural approaches: ABA with discrete trial training and pivotal response training, tracking progress on defined skills.^[8]
• Developmental approaches: speech and language therapy, occupational therapy, sensory integration and physical therapy; the Early Start Denver Model for children aged 12 to 48 months uses play and shared attention in natural settings.^[8]
• Educational approaches: structured teaching such as TEACCH, which builds on consistency and visual learning.^[8]
• Social-relational approaches: DIR/Floor Time, Relationship Development Intervention, Social Stories and social skills groups.^[8]
• Psychological approaches: cognitive-behavioural therapy for anxiety, depression and other co-occurring conditions.^[8]
• Communication supports: augmentative and alternative communication, sign, picture exchange and electronic devices where speech is limited.

Family involvement is central. For children with a diagnosis, further management should be needs-based: education plans, family support, coexisting-condition treatment, sleep and feeding management and transition planning. NICE CG128 expects information, support and a profile that travels with the child into education and social care.^[2]

Pharmacological treatment is justified only for co-occurring symptoms or conditions, never for the core features themselves.^[8] When a co-occurring disorder (ADHD, anxiety, depression, epilepsy, sleep disorder) is present, treat that disorder with its own evidence-based protocol, including methylphenidate or atomoxetine for ADHD within licensed indications.^[3] For severe irritability associated with autistic disorder in children and adolescents, two antipsychotics are licensed in several jurisdictions:

Both are antipsychotics and carry metabolic, endocrine, neurological and cardiovascular risks; baseline and ongoing monitoring (weight, height, glucose, lipids, prolactin, movement assessment, blood pressure) is required.^[3][4][5] Dose differs by CYP2D6 or CYP3A4 status for aripiprazole.^[5] Always weigh expected benefit against side effects and review regularly, lowering the dose when response is stable.^[4][5]

The overall plan is staged, beginning with prevention and assessment, then psychosocial intervention, then medication only for specific situations.

Assessment and care planning follow NICE CG158: involve the child or young person directly, gather information from parents and carers, school and peers, and assess core symptoms, functioning at home, at school or college and with peers, parenting quality and medical and psychiatric history.^[3] Assess for complicating factors, risks to self and others, abuse, physical health, educational needs, parental mental health and substance use.^[3] Conduct a comprehensive assessment under specialist supervision when complicating factors exist.^[3]

Psychosocial interventions. NICE CG158 recommends parent training for children aged 3 to 11 years who are at high risk of, or who have, oppositional defiant disorder or conduct disorder, or who are in contact with the criminal justice system for antisocial behaviour.^[3] The programme is based on social learning, uses modelling, rehearsal and feedback and should adhere to a manual that has been positively evaluated in a randomised controlled trial.^[3]

For young people, child-focused social and cognitive problem-solving programmes and, for conduct disorder at 11 to 17 years, multimodal interventions such as multisystemic therapy are offered.^[3] Early selective prevention at 3 to 7 years uses classroom emotional learning and problem-solving programmes of up to 30 classroom sessions over one school year.^[3]

Pharmacological management. Routine behavioural problems in ODD or CD are not treated with medication.^[3] ADHD co-occurring with ODD or CD is treated with methylphenidate or atomoxetine as in the NICE ADHD guideline.^[3] Risperidone may be considered for the short-term management of severely aggressive behaviour in young people with conduct disorder who have problems with explosive anger and severe emotional dysregulation despite psychosocial interventions, started at the lower end of the licensed range, with baseline and follow-up metabolic and movement monitoring, and reviewed after 3 to 4 weeks and stopped if there is no clinically important response by 6 weeks.^[3] This was off-label for some preparations in young people and for all preparations in children under 5 in the 2013 guideline.^[3]

Intermittent explosive disorder should be managed with anger-management and cognitive-behavioural approaches, treatment of co-occurring conditions and, where used, medication such as SSRIs or mood stabilisers under specialist care. The evidence base is smaller than for oppositional defiant disorder or conduct disorder, so practice varies by region. NICE CG158 does not provide a separate pharmacological protocol for intermittent explosive disorder, and the American Academy of Child and Adolescent Psychiatry practice parameters on disruptive behaviour disorders (2007) and on autism (2014) are commonly used in North American practice.^[3] Any prescribing should follow the local formulary, with the same metabolic and movement monitoring as for other antipsychotics.

In autism, common complications and coexisting conditions include intellectual disability, language disorder, ADHD, anxiety, depression, epilepsy, sleep and feeding disorders and gastrointestinal problems.^[2][6] Social exclusion, bullying, family stress and barriers to education and employment are frequent. Self-injurious behaviour and meltdowns may occur, usually in the context of overload, pain or communication difficulty rather than deliberate provocation.^[6][8]

In ODD and CD, complications include school exclusion, peer rejection, family breakdown, substance misuse, self-harm, violence towards others and, for CD, contact with the criminal justice system.^[3] Some young people with CD develop antisocial personality disorder, particularly when onset is early and there are callous-unemotional traits; many do not.^[3]

IED is associated with injury, relationship breakdown and, when outbursts are severe, legal consequences. Impulsive aggression can be a presenting feature of several other disorders, so recurring presentations should prompt reassessment.^[3]

Autism is a lifelong condition, but outcomes vary widely and are strongly influenced by language development, intellectual level, adaptive skills and the quality of early, needs-based support. Many people live independently, work and have relationships; others need substantial and continuing support. Early recognition and intervention improve developmental outcomes.^[1][8]

ODD often remits by adolescence, especially with effective parenting support, but it can progress to conduct disorder in some. CD has a more serious prognosis, though a substantial minority desist; persistent, early-onset CD is the group most at risk of ASPD. Positive school engagement and family support predict better outcomes.^[3]

IED tends to improve with early treatment of anger and comorbidity, but later onset and coexisting personality or substance use problems worsen the outlook. For all disruptive behaviour disorders, continuity of care through adolescence and into adult services is important.^[3]

Prevention has two strands: universal developmental monitoring and early intervention. CDC recommends surveillance at every health visit and standardised developmental screening at 9, 18 and 30 months, with autism-specific screening at 18 and 24 months and additional screening when risk is high, such as a sibling with ASD.^[1] The US Preventive Services Task Force concluded in 2016 that there was not enough evidence to recommend for or against universal screening of children aged 3 years or younger without signs or symptoms, and called for more research.^[1] Screening tools identify children who may need assessment; they do not diagnose.^[1][2]

Selective prevention for conduct problems begins in early childhood: classroom emotional learning and problem-solving programmes in schools with many at-risk children, and parent training where risk is identified.^[3] The aims are to interrupt coercive cycles, build problem-solving skills and keep children engaged in education.^[3]

Risk modification also includes avoiding valproate and topiramate in pregnancy unless there is no suitable alternative, treating parental mental illness, reducing family violence and supporting education.^[2]

Pregnancy. Maternal valproate or topiramate use in pregnancy, and paternal valproate use before conception, are associated with increased prevalence of autism.^[2] Antipsychotic safety in pregnancy follows product labelling; both risperidone and aripiprazole labels note that late third-trimester exposure may cause neonatal extrapyramidal or withdrawal symptoms.^[4][5] Pregnancy management needs obstetric and psychiatric coordination.

Children and adolescents. Most evidence and most service pathways are for children and young people. NICE CG128 covers recognition, referral and diagnosis for those under 19 years; NICE CG158 covers conduct and antisocial behaviour under 19.^[2][3] Diagnosis is most uncertain before 24 months and should be provisional, with review if needed.^[2] Autism services and conduct-disorder services overlap in adolescence, and both should plan transition to adult care.^[3]

Older adults. Autism in older adults is identified increasingly, often after a lifetime without diagnosis. Evidence-based guidance is limited. Principles are to reduce sensory overload, support communication, review medication that can worsen cognition, and avoid unnecessary antipsychotic or benzodiazepine use. For disruptive behaviour in dementia, antipsychotics are specifically not approved and carry an increased mortality warning, so their use belongs only in clearly defined circumstances.^[4][5]

• Developmental surveillance by trained primary care staff draws out most children who need help; formal tools are helpful but not essential, and a positive screen is not a diagnosis.^[1][2]
• Focus on a short, repeatable checklist of social milestones, hearing and vision checks, and observation of play; avoid tying up resources in tests that do not change care.^[2]
• Where specialist assessment is delayed, start practical support: parent coaching, school adjustments, communication routines, and management of epilepsy, sleep and gastrointestinal problems.^[8]
• For disruptive behaviour, parent management training can be delivered in groups by trained lay or community health workers following a manual.^[3]
• Antipsychotics should be reserved for severe, disabling symptoms after documented failure of psychosocial intervention, with the simplest reliable monitoring available.^[3][4]
• Link families to local education services, disability benefits and family support; continuity and clear records matter more than the number of sessions.

• ASD is a brain-based, early-onset neurodevelopmental spectrum defined by impaired social communication and restricted, repetitive behaviour.
• It is identified in around 1 in 31 children aged 8 years in the United States and is over three times more common in boys than girls.^[7]
• Diagnosis is clinical, based on ICD-11 or DSM-5-TR criteria after a structured specialist assessment; no test diagnoses or excludes ASD.^[2]
• Hearing and vision checks, a physical examination and a differential and coexisting-condition screen are required parts of assessment.^[2]
• Girls and verbally able children are often missed; under-ascertainment is a bigger problem than over-ascertainment.^[2]
• Behavioural, developmental and educational interventions have the strongest evidence; no medicine treats the core features.^[8]
• Risperidone and aripiprazole are licensed for irritability in autistic disorder in children and adolescents, with weight-based (risperidone) or fixed-range (aripiprazole) dosing, and need metabolic and movement monitoring.^[4][5]
• ODD, CD, IED and ASPD differ by age, intent, pattern of aggression and prognosis; ODD often remits and CD can progress.
• Parent management training, based on social learning, is the first-line psychosocial intervention for ODD and CD in children aged 3 to 11 years.^[3]
• Risperidone is considered only for severe aggressive behaviour in conduct disorder with explosive anger and dysregulation after psychosocial interventions have failed.^[3]
• Antipsychotics in dementia carry an increased mortality warning; their use in older adults requires clear justification.^[4][5]
• Early recognition and needs-based support improve outcomes across the autism spectrum.^[1]

Autism spectrum disorder in adults; attention deficit hyperactivity disorder; intellectual disability; anxiety disorders in children; disruptive sleep and feeding problems; antisocial personality disorder; psychopharmacology in children and adolescents; developmental delay; epilepsy; genetic counselling.

Throughout this page the word "disruptive behaviour disorder" refers to a behavioural presentation, not to an inference about the child or family. Neurodivergent people can present with distress-driven behaviour that is mistaken for wilful disruption, and that distinction should guide assessment.