Behaviour/personality change
Behaviour and personality change in adults is an important red flag in clinical practice.
It may present as aggression, apathy, disinhibition, poor judgement, emotional lability, or loss of empathy.
🌟 Key principle: always consider organic/neurological causes first before attributing to primary psychiatric illness.
🔍 Clinical Assessment
- 📚 History: From patient + collateral (family, carers). Onset, progression, triggers, risk behaviours, past psychiatric history, substance use, medications.
- 👀 Examination: Full neurological exam, cognitive assessment (MoCA, ACE-III), mental state exam (MSE).
- ⚠️ Red Flags: Acute confusion, seizures, focal neurology, rapid progression, systemic illness → urgent medical/neurology referral.
🧠 Causes of Behavioural/Personality Change
| Category |
Examples |
Clinical Clues |
| Neurological |
- Frontal lobe tumours
- Dementias (esp. frontotemporal dementia)
- Head trauma
- Stroke (esp. frontal or temporal)
- Epilepsy (temporal lobe)
|
Disinhibition, apathy, impaired executive function, seizures, focal neurological signs |
| Metabolic/Medical |
- Hypoglycaemia, hypoxia, uraemia, hepatic encephalopathy
- Electrolyte imbalance (Na, Ca)
- Endocrine (thyroid, adrenal)
|
Acute delirium, fluctuating confusion, systemic illness clues |
| Infective |
- Encephalitis (HSV, HIV, syphilis)
- Meningitis
- Sepsis-related delirium
|
Fever, meningism, headache, seizures, acute onset |
| Psychoactive Substances |
- Alcohol intoxication/withdrawal
- Illicit drugs (cocaine, amphetamines, cannabis)
- Prescription drugs (steroids, levodopa, antidepressants)
|
Temporal link with substance use or new medication |
| Primary Psychiatric |
- Depression
- Bipolar disorder
- Schizophrenia
- Personality disorders
|
Subacute or chronic course, younger age, no organic features |
🧪 Investigations
- 🩸 Bloods: FBC, U&E, LFTs, TFTs, glucose, calcium, B12/folate, CRP/ESR.
- 💉 Toxicology: Alcohol/drug screen if suspected.
- 🧲 Imaging: CT/MRI brain for tumours, strokes, structural lesions.
- 🔬 CSF: If encephalitis/meningitis suspected.
- 📊 Cognitive tests: Screening for dementia or delirium.
🛠️ Management Principles
- 🏥 Stabilise first: ABCDE, treat hypoxia, hypoglycaemia, sepsis.
- 💊 Treat underlying cause:
- Antibiotics for infection
- Thiamine + detox for alcohol withdrawal
- Correct metabolic/endocrine disturbances
- Surgery/oncology for tumours
- 🧠 Psychiatric care: If primary psychiatric disorder → antipsychotics, mood stabilisers, antidepressants, psychotherapy as appropriate.
- 👨👩👧 Multidisciplinary support: Neurology, psychiatry, social work, safeguarding teams.
🚩 Red Flags
- Rapidly progressive behavioural change in middle/older age → consider frontal lobe tumour or dementia.
- Acute onset with fever/headache → think encephalitis or meningitis.
- Alcohol/drug withdrawal with agitation → risk of delirium tremens or seizures.
- Behavioural change + focal neurology → stroke or tumour.
📈 Prognosis
✅ Depends entirely on the underlying cause. Some (e.g. infection, metabolic disturbance) are reversible with treatment.
⚠️ Others (e.g. dementia, brain tumours) carry a poorer prognosis and require long-term support.
🌟 The key clinical pearl: sudden or progressive personality change in adults must never be dismissed as "just psychiatric" without ruling out organic causes.
✅ Conclusion
Behavioural and personality change in adults is a red-flag presentation.
A structured approach — history, collateral, neurological exam, and targeted investigations — is essential to differentiate organic, psychiatric, and substance-related causes.
Early recognition and management can be life-saving.
