Behavioural change

Behavioural change is a new or marked departure from a person's usual conduct, personality, activity or social functioning, noticed by the patient or, more often, by family, carers, teachers or employers. It includes withdrawal, irritability, aggression, disinhibition, apathy, odd or risky acts, changes in sleep and appetite, and loss of previous interests. It is a nonspecific symptom with a very wide range of causes, from adjustment to stress through psychiatric disorder to delirium, dementia, intracranial disease, drugs and metabolic illness.

Definitions. Personality change is a persistent alteration of enduring patterns of thinking, feeling and acting, usually from frontal or limbic disease, substances or major psychiatric illness. Delirium is acute fluctuating disturbance of attention and awareness caused by a medical condition. Behavioural and psychological symptoms of dementia include agitation, aggression, apathy, wandering, disinhibition, psychosis, and sleep reversal.

In children and adolescents, behavioural change is judged against developmental stage and includes school refusal, regression, aggression, withdrawal, and self harm.

Classification by cause

• Delirium (acute): infection, drugs, metabolic disturbance, hypoxia, pain, retention, constipation, withdrawal, postoperative state.
• Neurodegenerative and cognitive: frontotemporal dementia, Alzheimer disease, dementia with Lewy bodies, vascular cognitive impairment, Huntington disease, and Parkinson disease.
• Structural and neurological: frontal or temporal tumour, subdural haematoma, stroke, traumatic brain injury, normal pressure hydrocephalus, epilepsy (temporal lobe, postictal), encephalitis (infectious, autoimmune), multiple sclerosis, and neurosyphilis.
• Endocrine and metabolic: thyroid disease, Cushing syndrome, Addison disease, hypoglycaemia, hyponatraemia, hypercalcaemia, uraemia, hepatic encephalopathy, vitamin B12, thiamine and niacin deficiency, porphyria, and Wilson disease.
• Psychiatric: depression, bipolar disorder, psychosis, anxiety, obsessive compulsive disorder, posttraumatic stress disorder, personality disorder, eating disorder, adjustment disorder, and attention deficit hyperactivity disorder.
• Substances and drugs: alcohol, cannabis, stimulants, hallucinogens, sedatives, anabolic steroids, corticosteroids, levodopa, antiepileptics, anticholinergics, benzodiazepines, isoniazid, efavirenz, mefloquine, montelukast, and withdrawal.
• Neurodevelopmental: autism and attention deficit hyperactivity disorder (change with transitions or stress), intellectual disability (behaviour as communication of pain or distress).
• Psychosocial: bereavement, trauma, abuse, bullying, relationship breakdown, job loss, and financial stress.
• Infection and systemic: HIV associated neurocognitive disorder, neurosyphilis, tuberculous meningitis, cerebral malaria, lupus, and paraneoplastic syndromes.

Epidemiology. Behavioural change is among the commonest reasons for psychiatric and neurological assessment. Delirium affects up to 30% of hospitalised older adults. Frontotemporal dementia causes dementia in about 10% to 20% of those with onset before 65 years. Autoimmune encephalitis (anti-N-methyl-D-aspartate receptor) typically affects young women with psychiatric onset. In adolescents, behavioural change commonly marks onset of depression, substance use, psychosis or abuse.

Mechanisms. Frontal and limbic circuit dysfunction (disinhibition, apathy, executive failure), diffuse cortical failure (delirium), neurotransmitter disturbance (dopaminergic excess in psychosis and mania, serotonergic and noradrenergic dysfunction in depression), drug effects, and psychological responses to stress, trauma and loss.

Key distinctions. Acute onset over hours to days with fluctuating attention and disorientation points to delirium. Insidious change over months in a person aged 40 to 65 years with disinhibition, loss of empathy, compulsive behaviours or apathy and preserved memory points to behavioural variant frontotemporal dementia. Onset over weeks with low mood, loss of interest and sleep change points to depression.

Elevated or irritable mood with reduced sleep and increased activity points to mania. New suspicious beliefs and hearing voices point to psychosis. Young person with psychiatric symptoms, seizures, movement disorder and reduced consciousness points to autoimmune encephalitis. Change after starting a new drug points to adverse reaction.

History

• Detailed description of the change from the patient and a close informant: what changed, when it began, how fast, and what is different from baseline (personality, work, relationships, interests, hygiene, spending, sexual behaviour, driving, alcohol).
• Time course: abrupt, stepwise, gradual, fluctuating, or episodic, and relation to events (illness, head injury, new medicines, surgery, bereavement, stress, substance use).
• Core symptoms: mood, anxiety, sleep, appetite, energy, concentration, memory, orientation, perceptual disturbance, delusions, thoughts of self harm or harm to others, obsessions, and compulsions.
• Behavioural features: apathy, disinhibition, aggression, wandering, hoarding, compulsive eating (sweet craving), repetitive behaviours, inappropriate social or sexual behaviour, and loss of insight.
• Neurological symptoms: headache, seizures, vomiting, visual change, weakness, gait problems, incontinence, tremor, and movement disorder.
• Systemic symptoms: fever, weight loss, infection, pain, cough, urinary symptoms, constipation, and change in thirst or urination.
• Medical and psychiatric history, head injury, substance use, family history (dementia, psychiatric illness, Huntington disease), sexual history and HIV risk.
• Drug history including over the counter drugs and herbal products, new drugs, and recent changes.
• Social: living situation, finances, abuse, bullying, work or school performance, and safeguarding concerns.
• Child and adolescent: developmental milestones, school reports, peer relations, online activity, abuse, substance use, and family functioning.
• Safety: suicidal thoughts, aggression, wandering, fire risk, vulnerability to exploitation, driving, firearm or weapon access, and ability to care for dependants.

Examination

• Vital signs: temperature, pulse, blood pressure, respiratory rate, oxygen saturation, glucose, weight, and height.
• General: hydration, nutrition, signs of infection, thyroid, liver or kidney disease, alcohol or drug use, injuries, and neurocutaneous signs.
• Mental state: appearance and behaviour, speech, mood and affect, thought form and content, perceptual abnormalities, cognition (orientation, attention, memory), insight and judgement, and risk.
• Cognitive screening: 4AT for delirium, Montreal Cognitive Assessment (under 26 of 30 suggests impairment), frontal assessment battery, and clock drawing. Informant tools (AD8).
• Neurological: cranial nerves (smell, fundoscopy for papilloedema, visual fields), primitive reflexes (grasp, palmomental, snout), tone, tremor, gait, reflexes, plantar responses, chorea, and focal deficits.
• Systemic examination: chest, abdomen (bladder, faecal loading), skin, and joints.
• Rating tools: PHQ-9, GAD-7, Young Mania Rating Scale, Neuropsychiatric Inventory, and Strengths and Difficulties Questionnaire in children.

Red flags

• Acute onset or fluctuating consciousness (delirium) or any new confusion.
• Fever, meningism, or immunosuppression.
• Head injury, anticoagulation, or falls (subdural haematoma).
• Headache with vomiting, papilloedema, new seizures, or focal neurological signs (tumour, raised intracranial pressure).
• Rapidly progressive cognitive decline over weeks to months (Creutzfeldt-Jakob disease, autoimmune encephalitis).
• Young person with new psychosis, seizures, movement disorder or autonomic instability (autoimmune encephalitis).
• Suicidal ideation, plan or intent, or homicidal thoughts.
• Command hallucinations, severe agitation, aggression, or violence.
• Self neglect, dehydration, malnutrition, or inability to care for dependants.
• Suspected abuse, neglect, coercion or exploitation, and children at risk.
• Substance intoxication or withdrawal, or recent overdose.
• New onset behavioural change after age 40 years in someone with no psychiatric history.
• Drug started in the past weeks (corticosteroids, antiepileptics, isoniazid, efavirenz, levodopa).
• Catatonic features: mutism, posturing, negativism, or stupor.
• Behavioural change in a child with sudden regression, school refusal after trauma, or unexplained injuries.

Special groups

• Children: behaviour is a form of communication. Assess pain, hunger, vision and hearing, sleep, school, bullying, abuse, loss and family stress. Developmental regression needs urgent neurological assessment.
• Adolescents: depression, substance use, psychosis, eating disorders, trauma, gender and sexuality distress, and social media exposure. Interview the adolescent alone for part of the assessment.
• Older adults: delirium is the first diagnosis to exclude, followed by depression, drug effect, infection, constipation, pain, and dementia.
• Pregnancy and postpartum: postpartum psychosis, depression, thyroiditis, eclampsia, and anaemia.
• People with intellectual disability and autism: unexplained behavioural change often signals pain, constipation, dental disease, seizures, abuse, or change in routine.
• Chronic physical illness and cancer: steroids, hypercalcaemia, brain metastases, and depression.
• Region specific: HIV related brain disease, cerebral malaria, neurocysticercosis, tuberculous meningitis, neurosyphilis, khat and alcohol use, and traditional medicines.

Acute and reversible

• Delirium due to infection (urinary, respiratory, meningitis, sepsis), drugs, withdrawal, hypoxia, hypoglycaemia, electrolyte disturbance, uraemia, hepatic encephalopathy, pain, urinary retention, constipation, and postoperative state.
• Intoxication with alcohol or drugs, and poisoning (carbon monoxide).
• Thyrotoxicosis, myxoedema, adrenal crisis, hypercalcaemia, and porphyria.
• Nonconvulsive status epilepticus and postictal state.

Neurological and neurocognitive

• Frontotemporal dementia, Alzheimer disease, dementia with Lewy bodies, vascular cognitive impairment, and Creutzfeldt-Jakob disease.
• Brain tumour (frontal, temporal, corpus callosum), subdural haematoma, stroke, normal pressure hydrocephalus, and traumatic brain injury.
• Autoimmune encephalitis (anti-N-methyl-D-aspartate receptor, limbic), herpes simplex encephalitis, neurosyphilis, HIV encephalopathy, and neurocysticercosis.
• Huntington disease, Wilson disease, Parkinson disease, multiple sclerosis.
• Temporal lobe epilepsy.

Psychiatric

• Major depressive disorder, bipolar disorder (mania, hypomania, mixed states), and psychotic disorders (schizophrenia, delusional disorder, brief psychotic disorder).
• Anxiety disorders, obsessive compulsive disorder, posttraumatic stress disorder, adjustment disorder, grief reaction.
• Catatonia.
• Personality disorders and impulse control disorders.
• Eating disorders and substance use disorders.
• Attention deficit hyperactivity disorder and autism spectrum disorder.
• Conduct disorder, oppositional defiant disorder, and disruptive mood dysregulation disorder in children.
• Factitious and somatic symptom disorders.

Drugs and toxins

• Corticosteroids, anabolic steroids, antiepileptics (levetiracetam, perampanel, topiramate), levodopa and dopamine agonists, isoniazid, efavirenz, mefloquine, montelukast, interferon, benzodiazepines, anticholinergics, and stimulants.
• Lead, mercury, and other heavy metals.

Psychosocial

• Abuse, neglect, bullying, violence, bereavement, trauma, relationship or job loss, and cultural or migration stress.

Step 1. Exclude emergencies and assess risk. Check vital signs, glucose, oxygen saturation, level of consciousness, and signs of delirium (4AT). Assess suicide and violence risk, safeguarding, and capacity. Treat intoxication, withdrawal and life threatening illness first.

Step 2. Characterise the change. Obtain an informant history of onset, pace, pattern and baseline function. Perform a full mental state and cognitive examination, and a neurological and general examination. Review every drug.

Step 3. First line tests

• Capillary glucose, full blood count, urea, creatinine, electrolytes (sodium), calcium, magnesium, phosphate, liver tests, thyroid stimulating hormone, vitamin B12, folate, C-reactive protein, and erythrocyte sedimentation rate.
• Urinalysis and culture, chest radiograph if respiratory signs, and ECG.
• Urine drug screen and blood alcohol; paracetamol and salicylate levels if overdose is possible.
• HIV and syphilis serology.
• Pregnancy test in women of reproductive age.

Step 4. Targeted tests

• CT head (non contrast) when there is acute change, head injury, anticoagulation, focal signs, headache with red flags, seizure, or age over 60 years with new behavioural change; MRI brain with contrast for subacute and progressive change, frontotemporal pattern, encephalitis, and tumour.
• Electroencephalogram for fluctuating consciousness, suspected nonconvulsive status, or encephalitis (slowing, extreme delta brush).
• Lumbar puncture (after imaging) with cell count, protein, glucose, culture, herpes simplex virus polymerase chain reaction, cryptococcal antigen, venereal disease research laboratory test, autoimmune antibodies (serum and cerebrospinal fluid anti-N-methyl-D-aspartate receptor, anti-leucine rich glioma inactivated 1, voltage gated potassium channel complex), oligoclonal bands, and 14-3-3 protein.
• Autoantibodies (antinuclear antibodies, anti-double stranded DNA), antithyroid peroxidase antibodies, paraneoplastic panel, and imaging for malignancy (CT chest, abdomen and pelvis, pelvic ultrasound for ovarian teratoma).
• Copper, caeruloplasmin and slit lamp examination for Wilson disease in people under 50 years.
• Cortisol, parathyroid hormone, and testosterone as indicated; 24 hour urine copper; lead level.
• Neuropsychological testing, and PET or SPECT when diagnosis of dementia type is unclear.
• Genetic testing (Huntington disease, C9orf72, progranulin, microtubule associated protein tau) in familial frontotemporal dementia or movement disorder, with counselling.
• Formal developmental and autism assessment in children as indicated.

Step 5. Interpretation. Diagnose delirium by 4AT or the Confusion Assessment Method (acute onset and fluctuating course, inattention, and either disorganised thinking or altered consciousness), then find and treat causes.

A primary psychiatric diagnosis is made only after reasonable exclusion of organic causes, and organic disease is considered again when psychiatric symptoms are atypical, of late onset, treatment resistant, or accompanied by neurological features. Frontotemporal dementia is suggested by behaviour change with frontotemporal atrophy on imaging and preserved memory early in disease. Always review diagnosis at follow up.

Limits. Normal CT does not exclude encephalitis, small tumours, or frontotemporal dementia. Screening cognitive tests are affected by education, language, mood and delirium. Antibody tests can be falsely positive at low titre. Collateral history can be biased.

Immediate

• Ensure safety: a calm, low stimulation environment, de-escalation by a trained person, removal of dangerous objects, and enhanced observation when risk is present. Use the least restrictive measures. Restraint only as a last resort with senior approval and monitoring.
• Treat life threatening causes: hypoglycaemia (50 mL of 50% dextrose or 150 to 200 mL of 10% dextrose after thiamine), hypoxia, sepsis, seizures, and withdrawal.
• Delirium: treat the cause, restore sleep wake cycle, hydrate, correct electrolytes, relieve pain, treat constipation and retention, provide glasses and hearing aids, reorient, mobilise, and avoid sedatives where possible. For severe distress or danger: haloperidol 0.5 to 1 mg orally or intramuscularly (older adults) or 2 to 5 mg (younger adults), repeated after 1 hour if needed (maximum 5 mg daily in frail older adults, 12 mg in adults), after ECG; or olanzapine 2.5 to 5 mg orally. Avoid in Parkinson disease and Lewy body dementia (use quetiapine 12.5 to 25 mg), and avoid benzodiazepines except for alcohol or sedative withdrawal and seizures.
• Acute agitation with aggression in adults when de-escalation fails: lorazepam 1 to 2 mg orally or intramuscularly (maximum 4 mg in 24 hours) or olanzapine 5 to 10 mg orally (maximum 20 mg in 24 hours), or haloperidol 5 mg intramuscularly (maximum 12 mg in 24 hours) with promethazine 25 to 50 mg intramuscularly in antipsychotic naive patients. Do not give intramuscular olanzapine within 1 hour of a parenteral benzodiazepine. Monitor pulse, blood pressure, oxygen saturation and consciousness every 15 minutes for 1 hour, then hourly.
• Suicidal ideation or intent: continuous observation, remove means, and urgent psychiatric assessment.
• Catatonia: lorazepam 1 to 2 mg intravenously (lorazepam challenge), repeated after 3 hours, then 1 to 2 mg every 8 hours, titrated to response (up to 8 to 24 mg daily), with urgent psychiatric review for electroconvulsive therapy and avoidance of antipsychotics.
• Encephalitis suspected: aciclovir 10 mg/kg intravenously every 8 hours (adjusted for renal function) and ceftriaxone 2 g every 12 hours with early lumbar puncture, then immunotherapy for autoimmune encephalitis (methylprednisolone 1 g intravenously daily for 3 to 5 days, with immunoglobulin 0.4 g/kg daily for 5 days or plasma exchange) under neurology.
• Raised intracranial pressure or tumour: head up 30 degrees, dexamethasone 10 mg intravenously then 4 mg every 6 hours for vasogenic oedema, and neurosurgical referral.
• Wernicke encephalopathy suspected: thiamine 500 mg intravenously three times daily for 2 to 3 days.

Treatment by cause

• Delirium: treat underlying illness, stop deliriogenic drugs, nonpharmacological care, and delirium prevention (sleep, mobility, hydration, nutrition, orientation).
• Depression: psychological therapy and sertraline 50 mg daily (25 mg for the first week), increased to 50 to 200 mg, or escitalopram 10 mg increased to 20 mg (10 mg over 65 years). Review at 2 weeks and 4 to 6 weeks, continue for at least 6 to 12 months after remission.
• Bipolar disorder (mania): stop antidepressants and stimulants, olanzapine 10 mg daily (maximum 20 mg) or risperidone 2 mg increased to 4 to 6 mg or quetiapine 50 mg at night increased over 4 days to 400 to 800 mg or aripiprazole 15 mg (maximum 30 mg), with lithium (target level 0.6 to 1.0 mmol/L, up to 1.2 mmol/L in acute mania) or valproate 20 to 30 mg/kg daily in men and in women who cannot become pregnant.
• Psychosis: olanzapine 5 to 10 mg, risperidone 1 to 2 mg (maximum 6 mg), or aripiprazole 10 to 15 mg (maximum 30 mg), adjusting to response over 4 to 6 weeks, with early specialist care; clozapine 12.5 mg increased to 300 to 450 mg (maximum 900 mg) with blood count monitoring (weekly for 18 weeks, then fortnightly to 1 year, then monthly) for treatment resistant illness.
• Anxiety and posttraumatic stress disorder: psychological therapy and sertraline, or escitalopram 10 mg increased to 20 mg (10 mg over 65 years); prazosin 1 mg at night titrated to 3 to 15 mg (maximum 20 mg) for trauma nightmares.
• Frontotemporal dementia: environmental and behavioural management, sertraline 25 to 50 mg or trazodone 25 to 50 mg at night for disinhibition, compulsions and irritability, carer support; avoid cholinesterase inhibitors and minimise antipsychotics.
• Alzheimer disease and dementia with Lewy bodies: donepezil 5 mg daily increased to 10 mg after 4 to 6 weeks, memantine 5 mg daily increased weekly to 20 mg daily for moderate to severe disease; behavioural symptoms first by nondrug measures, risperidone 0.25 to 0.5 mg twice daily (maximum 2 mg daily) only for severe distress or danger, for the shortest time (reassess after 6 weeks) with informed consent about stroke and mortality risk.
• Epilepsy: antiepileptic drugs by seizure type, avoiding drugs causing behavioural effects when alternatives exist.
• Thyroid disease: carbimazole 15 to 40 mg daily with propranolol 10 to 40 mg three to four times daily for hyperthyroidism, levothyroxine 1.6 micrograms/kg daily for hypothyroidism.
• Drug induced change: reduce or stop the culprit (for example corticosteroids to lowest effective dose, or switch levetiracetam), with pyridoxine 10 to 50 mg daily for isoniazid.
• Substance use: brief intervention, withdrawal management, and addiction treatment.
• Neurosyphilis: benzylpenicillin 18 to 24 million units daily intravenously (3 to 4 million units every 4 hours) for 10 to 14 days. HIV: antiretroviral therapy. Neurocysticercosis: albendazole 15 mg/kg daily for 10 to 14 days with dexamethasone and antiepileptics.
• Autism and intellectual disability: look for pain and illness, adjust environment and routine, behavioural support and communication aids; avoid antipsychotics except short term for severe aggression (risperidone 0.25 to 0.5 mg, maximum 2 mg daily in children, with metabolic monitoring).
• Children and adolescents: family and school involvement, parenting programmes for conduct problems, cognitive behavioural therapy for anxiety and depression, fluoxetine 10 mg increased to 20 mg for depression (after psychological therapy), and treatment of attention deficit hyperactivity disorder as indicated. Child protection referral when abuse or neglect is suspected.
• Bereavement and adjustment: support, normalisation, brief psychological therapy; avoid routine sedatives; review if persistent beyond 6 to 12 months or if depressive features appear.

Special populations

• Pregnancy and postpartum: urgent assessment for postpartum psychosis (admission with a mother and baby unit), depression and thyroid disease; lithium and valproate need specialist advice.
• Older adults: lower doses, avoid anticholinergics and benzodiazepines, monitor for falls, and check sodium on antidepressants.
• Liver and kidney impairment: adjust doses; use lorazepam or oxazepam rather than long acting benzodiazepines.
• Capacity and legal framework: assess capacity for each decision, and use the relevant mental health or mental capacity law for compulsory care when risk is high and the patient lacks capacity or refuses necessary treatment.

Monitoring. Vital signs and consciousness, 4AT daily in delirium, behaviour charts, mental state and risk review at each contact, mood scales, sleep, nutrition and hydration, drug adverse effects (QTc with antipsychotics, metabolic parameters, sodium, lithium levels), and cognitive testing at 3 to 6 months.

Referral and escalation. Psychiatry for suicidal ideation, psychosis, mania, severe depression, catatonia and complex presentations. Neurology for seizures, suspected encephalitis, rapid decline, focal signs, and movement disorders. Old age psychiatry or memory clinic for suspected dementia. Neurosurgery for tumour or haematoma. Paediatric or adolescent mental health services for children. Social services and safeguarding teams when there is abuse, neglect or vulnerability. Substance misuse services.

Admission criteria. Delirium, suspected encephalitis or intracranial lesion, high suicide or violence risk, psychosis or mania with risk, catatonia, severe self neglect, intoxication or withdrawal needing inpatient care, unsafe environment, and failure of community management.

Discharge and follow up. Written plan and information for the patient and carers, medication with limited supply, safety plan, review within 1 week (within 48 hours for recent suicidal thoughts), then regularly. Safety net advice: return for new confusion, drowsiness, seizure, severe headache, fever, suicidal thoughts, violence, hearing voices that give commands, refusal to eat or drink, or rapid worsening.