CASC Knowledge Essentials06 · Child and adolescent psychiatry
06 · Child and adolescent psychiatry
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Written by Resident Doctor Committee · Published
6.1 Development: delay, difference and regression
Delay means acquiring a skill later than expected. Skills develop unevenly: fluent vocabulary may coexist with poor social understanding, and good non-verbal reasoning with a language disorder. One strong skill does not define developmental level.
Regression means losing an established skill. Language, social, motor or continence loss needs an explanation: hearing loss, epilepsy, neurological illness, depression, trauma and environmental disruption can alter functioning. Motor regression particularly suggests a neurological process. NICE distinguishes early social/language regression from later language regression or motor regression, which require paediatric/neurological assessment.
New silence after previously speaking comfortably everywhere is not automatically selective mutism. New inattention after severe sleep disruption is not automatically ADHD. A developmental condition can coexist with an acquired disorder.
6.2 ADHD: what the diagnosis requires
Core features
ADHD involves developmentally excessive inattention and/or hyperactivity–impulsivity, with functional impairment. ICD-11 requires a pattern lasting at least six months, significant symptoms before age 12, and evidence across situations.
Domain | Typical presentation |
|---|---|
Inattention | Loses possessions, misses detail, leaves tasks unfinished, forgets, struggles to organise |
Hyperactivity | Fidgets, leaves the seat, climbs or moves excessively; later may feel internally restless |
Impulsivity | Interrupts, blurts out, cannot wait, acts before considering danger |
These behaviours may be mistaken for laziness or deliberate non-compliance. Being absorbed in a rewarding video game neither confirms nor excludes ADHD. Developmental assessment and information across settings establish the diagnosis; Conners and other rating scales support it.
ICD-11 requires several developmentally excessive symptoms, without a fixed numerical count. ADHD and autism can be diagnosed together.
Differential, comorbidity and course
Alternative explanation | Useful distinction |
|---|---|
Anxiety or depression | Concentration changes with worry or a mood episode |
Poor sleep or hearing impairment | Physiological/sensory difficulty can look like inattention |
Intellectual disability or learning disorder | Judge demands against developmental and learning abilities |
Trauma/adversity | Timing and associated threat-related symptoms matter |
Absence seizures | Brief stereotyped interruptions rather than continuous distractibility |
Classroom-specific difficulty | Consider the educational demand, bullying or an unrecognised learning problem |
Autism, tics, oppositional/conduct problems, anxiety and learning disorders commonly coexist. Consequences include low self-esteem, family conflict, underachievement, injury and later substance misuse. Motor hyperactivity often becomes less obvious with age; executive difficulties may persist. Do not promise that a child will grow out of ADHD.
Treatment sequence
Environmental adjustments reduce demands on attention and inhibition. Parent programmes and school support make expectations manageable and consistent; their value does not imply that parenting caused ADHD. Medication response depends on the preparation, duration and tolerability.
Age/situation | NICE sequence |
|---|---|
Under five | Parent training first; medication requires a second specialist opinion, ideally from a tertiary service |
Five and over | Methylphenidate first |
Insufficient benefit after an adequate six-week methylphenidate trial | Consider lisdexamfetamine |
Stimulants not tolerated or adequate trials insufficient | Atomoxetine or guanfacine |
Some age/formulation uses are off-label: a NICE recommendation does not make every product licensed for that use.
6.3 ADHD medicines: the knowledge behind monitoring
Medicine | Mechanism | Adverse effects to retain |
|---|---|---|
Methylphenidate | Dopamine/noradrenaline reuptake inhibition | Reduced appetite, weight/growth effects, insomnia, abdominal discomfort, headache, raised pulse/BP; possible agitation, tics, psychotic/manic symptoms |
Lisdexamfetamine / dexamfetamine | Lisdexamfetamine is converted to dexamfetamine, increasing catecholamine signalling | Similar stimulant effects; consider misuse/diversion and duration |
Atomoxetine | Selective noradrenaline reuptake inhibition | Nausea, appetite change, headache, sleep disturbance, raised pulse/BP; rare serious liver injury; suicidal-thinking monitoring, particularly in children/adolescents |
Guanfacine | Alpha-2A adrenergic agonism | Somnolence, fatigue, hypotension, bradycardia, syncope; rebound BP/heart-rate increase after abrupt withdrawal |
Atomoxetine: the suicidal-behaviour trial signal concerned children/adolescents; adult trials did not show the same placebo difference. Stop for jaundice or laboratory evidence of liver injury and do not rechallenge. Guanfacine: withdraw gradually and monitor more closely during titration.
Baseline and follow-up
Record growth, appetite, sleep, pulse, BP and cardiac history. Exertional syncope, cardiac-type chest pain, a murmur, congenital heart disease or sudden death in a first-degree relative under 40 warrant further cardiovascular assessment.
Measure | NICE monitoring interval |
|---|---|
Height | Six-monthly |
Weight, age ten or younger | Three-monthly |
Weight, over ten | Three and six months after starting, then six-monthly; sooner for concerns |
Pulse/BP | Before and after dose changes, then six-monthly |
Routine ECGs and blood tests are unnecessary without an indication. Review benefit, mood, sleep, tics, adherence and diversion. Planned breaks may clarify continuing need or address growth problems; weekend omissions are not a universal rule.
6.4 Autism: the two diagnostic domains
Autism combines persistent reciprocal social communication/interaction differences with restricted, repetitive or inflexible behaviour, interests or activities. Features begin during development, sometimes becoming obvious only when social demands increase.
Area | Examples |
|---|---|
Shared attention/reciprocity | Limited pointing to share interest, unusual back-and-forth exchange, difficulty sharing enjoyment |
Communication | Differences in gesture, expression, tone, conversation or implied meaning |
Relationships/play | Difficulty adjusting to social contexts; inflexible imaginative play or unusual friendship patterns |
Repetition/inflexibility | Repetitive movement/speech, strong routines, distress with change, intense interests |
Sensory features | Hyperreactivity, hyporeactivity or sensory seeking: sounds, textures, pain or particular experiences |
Language delay and intellectual disability are not required. Fluent speech can coexist with substantial communication needs. Girls and children using learned social scripts may be recognised later. “Asperger syndrome” is a historical term, not a separate ICD-11 diagnosis.
Developmental history, observation, functioning and collateral information are combined. ADOS and ADI-R are aids, not stand-alone diagnostic tests. Hearing/language disorders, intellectual disability, social anxiety, selective mutism, ADHD and severe neglect-related difficulties can resemble or coexist with autism.
Coexisting illness and treatment
Epilepsy, ADHD, anxiety, depression, sleep disturbance, restricted eating and intellectual disability are common associations. Sudden deterioration still needs a differential: pain or constipation may appear as agitation or self-injury.
Support targets communication, functioning, sensory needs and coexisting conditions. No medication is recommended for core autism features. Antipsychotics have a specialist role in severe behaviour that challenges when other interventions are insufficient or cannot be delivered because of severity. Define the target, review at three–four weeks, and stop at six weeks without a clinically important response.
Regression and associated syndromes
Rett syndrome: early developmental slowing followed by loss of purposeful hand use and language, hand-wringing, gait difficulty and often epilepsy. It predominantly affects girls and is associated with MECP2 variants; it is not simply severe autism.
Fragile X, tuberous sclerosis and Down syndrome have increased autism associations. Dysmorphism, intellectual disability, unusual skin findings or seizures guide further investigation. Genetic tests and EEG are not routine tests “for autism”.
6.5 Conduct disorder and oppositional defiant disorder
Conduct-dissocial disorder is persistent violation of others' rights or major age-appropriate rules. Its domains are aggression to people/animals, property destruction, deceit/theft and serious rule violations. Severity reflects harm and breadth of behaviour.
Oppositional defiant disorder | Conduct-dissocial disorder | |
|---|---|---|
Core pattern | Angry/irritable, argumentative, defiant or vindictive | Serious rights violations and major antisocial behaviour |
Examples | Arguments, provocation, blaming others | Cruelty, assault, coercion, serious theft, fire-setting, major rule-breaking |
Duration in ICD-11 | Prolonged, typically six months or more | Prolonged, typically twelve months or more |
An isolated act or ordinary adolescent conflict is insufficient. ICD-11 requires an enduring pattern of dissocial behaviour. Childhood onset and limited prosocial emotions are relevant qualifiers; lack of remorse requires a sustained pattern, not one guarded interview.
Consider ADHD, learning problems, depression, trauma, family adversity, harsh/inconsistent discipline, peers and substances. Adversity does not prove parental causation.
Parent training, problem-solving and multimodal family/community interventions are the main treatments. Medication is not routine. Short-term risperidone is reserved for selected severe aggression after insufficient psychosocial benefit. Remember weight/metabolic effects, hyperprolactinaemia, movement disorders and QT effects.
6.6 Enuresis: what must be excluded
Enuresis is repeated wetting beyond the expected age/developmental stage for bladder control, generally from five. Primary enuresis has no established sustained dryness; secondary enuresis returns after at least six months dry. Separate night-time wetting from daytime urgency, frequency, incontinence or abnormal voiding.
Constipation is a common contributor, including overflow “diarrhoea”. Consider infection, diabetes, sleep problems and urinary/neurological abnormalities. Thirst, polyuria, weight loss or systemic illness increases urgency. Stress, bullying or maltreatment may precede secondary wetting, but wetting alone does not diagnose abuse.
Treatment | Knowledge to retain |
|---|---|
Alarm | Builds a sustained response to bladder filling |
Desmopressin | Reduces overnight urine production; useful for rapid dryness or when alarms are unsuitable; relapse after stopping is common |
Imipramine | Specialist later option; dangerous in overdose |
Desmopressin requires fluid restriction from one hour before to eight hours after dosing to prevent water retention and hyponatraemia. Ordinary enuresis management otherwise encourages adequate daytime fluids.
6.7 Selective mutism
Speech is possible in some settings but consistently unavailable in others where expected. This anxiety disorder requires at least one month under ICD-11, beyond the first month of school, with functional interference. Unfamiliarity with the language or a primary communication disorder must not adequately explain it.
Hearing/language difficulties can coexist. Autism requires its own developmental pattern, and dual diagnosis is possible. The older term “elective mutism” wrongly suggests choice.
Treatment reduces speaking-related anxiety through graded exposure across people and settings. Stimulus fading gradually introduces people while the child speaks with someone trusted. Shaping reinforces steps towards the intended communication. Address speech/language needs separately.
6.8 Adolescent self-harm and depression
Self-harm includes intentional poisoning or injury regardless of apparent purpose. Intent may be absent, mixed, fluctuating or substantial. Medical lethality and expected lethality are separate facts: a small overdose may involve high intent, and later help-seeking does not erase a wish to die.
Consider depression, anxiety, trauma, psychosis, substances and neurodevelopmental difficulties. Adolescent depression may appear as irritability, withdrawal and falling school performance. Persistent low mood/loss of interest, associated symptoms and impairment establish an episode; psychosis, mania and substances alter the differential.
Fluoxetine has the strongest established antidepressant role. It is not routine initial treatment for mild depression. In 12–18-year-olds with moderate–severe depression, initial fluoxetine plus psychological therapy is an option; failed therapy is not always a prerequisite. Specialist assessment and close early monitoring matter, particularly for hostility, activation, self-harm and suicidal thinking.
After self-harm, risk scores or “low/medium/high” categories should not decide discharge. General-hospital admission depends on unresolved safety/safeguarding needs or inability to participate in assessment; under sixteen does not automatically mean overnight admission. Assessment can run alongside physical treatment. Continuing safety concerns require initial aftercare within 48 hours of the psychosocial assessment.
Paracetamol poisoning
Early wellness does not exclude delayed severe liver injury. Acetylcysteine is the antidote and works best promptly. Concentration interpretation requires a reliable ingestion time; the standard nomogram is unsuitable for staggered or uncertain-time ingestion. Treatment follows current toxicology guidance.
6.9 Maltreatment and its psychiatric consequences
Maltreatment includes physical, sexual and emotional abuse, neglect, exploitation and fabricated/induced illness. Possible indicators include injuries inconsistent with development or the account, recurrent unexplained injury, genital symptoms, regression, fear of particular people, unusual sexualised behaviour and abrupt behavioural change. No single behavioural sign proves abuse.
Consequences include depression, PTSD, complex PTSD, dissociation, self-harm, sleep problems and impaired trust/attachment. PTSD involves re-experiencing in the present, avoidance and persistent threat; complex PTSD adds difficulties with emotional regulation, self-concept and relationships. Maltreatment is distinct from any one consequence.
A disclosure creates a safeguarding concern before proof is available. Clinical assessment addresses immediate needs; trained safeguarding/investigative teams establish the wider account. Repeated leading questions can compromise evidence.