Homicidal IdeationMANAGEMENT

PSYCHIATRIC PRESENTATIONS · 12 SECTIONS

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504 items

☷ Legend

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Cardiovascular Presentations71▾

Respiratory Presentations52▾

Neurological Presentations83▾

Gastrointestinal Presentations74▾

Genitourinary and Reproductive Presentations48▾

Infectious Disease Presentations148▾

Trauma Presentations89▾

Toxicologic Presentations80▾

Psychiatric Presentations26▾

Acute anxiety Acute psychosis Agitation-behavioral emergency Anorexia Nervosa (Medical Complications)Bipolar disorder Bipolar Disorder (Depressive Episode)Bipolar Disorder (Manic Episode)Bulimia Nervosa (Medical Complications)Catatonia Conversion disorder Dementia and behavioral crisis Factitious Disorder Failure to Cope (Social)Failure to Thrive Generalized Anxiety Disorder Homicidal Ideation Major Depressive Disorder Major depressive episode Malingering Neuroleptic malignant syndrome Panic Attack Post-Traumatic Stress Disorder (Acute)Schizophrenia Exacerbation Suicidal Ideation Suicidal ideation and attempt Suicide Attempt

Musculoskeletal and Rheumatologic Presentations96▾

Dermatology Presentations23▾

Environmental and Exposure Presentations27▾

Hematologic and Oncologic Presentations36▾

Pediatric-Specific Presentations19▾

Endocrine and Metabolic Presentations45▾

ENT and Maxillofacial Presentations27▾

Ophthalmologic Presentations19▾

Obstetric Presentations23▾

Systemic and Miscellaneous Presentations17▾

01Approach to the Critical Patient/attcp32

Immediate safety priorities

›Scene and patient safety

›Security personnel at bedside or immediately available

›Perform weapon search per institutional protocol before examination

›Conduct interview with door open and provider nearest to exit

›Remove potential weapons from room environment

›Threat level determination

›Specific identified target with organized plan — highest acuity

›Active psychosis with command hallucinations to harm others

›Access to firearms or other lethal means

›Concurrent high-risk suicidal ideation requiring simultaneous management

›Escalation triggers

›Escalating agitation or threatening behavior

›De-escalation techniques first-line

›Rapid tranquilization if verbal measures fail

›Active aggression toward staff or others

›Security code activation

›Physical restraint as last resort with continuous monitoring

›Inability to safely assess due to extreme agitation

›Rapid tranquilization to permit safe evaluation

Stabilization and monitoring

›Agitation monitoring

›Standardized agitation scale at triage and reassessment

›Positive Agitation Sedation Scale (PASS) or STAMP tool for escalation tracking

›Continuous observation during ED stay

›Medical stabilization

›Vital signs: tachycardia and hyperthermia suggest sympathomimetic toxidrome or excited delirium

›Blood glucose at bedside — hypoglycemia mimics psychiatric emergency

02History/hx53

Nature of ideation

›Ideation spectrum characterization

›Passive vs. active ideation

›Ego-syntonic vs. ego-dystonic quality

›Intrusive or unwanted vs. deliberate and purposeful

›Frequency, intensity, and duration of thoughts

›Escalating vs. stable pattern

Specificity of plan

›Plan and intent assessment

›Identified target — named individual or group

›Specific method or plan formulated

›Access to means: firearms, weapons, medications

›Recent acquisition of weapons or surveillance of target

›Intent to act and perceived ability to carry out plan

Triggers and context

›Precipitating factors

›Interpersonal conflict or perceived betrayal

›Paranoid delusions or persecutory beliefs

›Command auditory hallucinations directing harm

›Acute intoxication — stimulants, PCP, synthetic cannabinoids, alcohol

›Recent loss, humiliation, job loss, or relationship breakdown

›Legal problems or financial instability

›Statements of "nothing to lose" or nihilistic thinking

Prior violence history

›Historical risk indicators

›Prior assaults, homicide attempts, or arrests for violence

›Restraining orders or protective orders issued against patient

›Animal cruelty or property destruction

03Physical Exam/exam34

Safety during examination

›Pre-examination precautions

›Weapon search completed before physical contact

›Security personnel immediately available

›Provider positioned near exit

›Calm, non-confrontational approach during examination

Vital signs and general appearance

›Hemodynamic and temperature assessment

›Tachycardia — sympathomimetic intoxication, excited delirium, anxiety

›Hypertension — stimulant toxidrome, agitation

›Hyperthermia — stimulant intoxication, neuroleptic malignant syndrome, excited delirium

›Level of agitation and psychomotor activity

›Diaphoresis and tremor — withdrawal or intoxication states

Neurological examination

›Mental status and neurologic assessment

›Orientation to person, place, time, and situation

›Attention and concentration — screen for delirium

›Memory and cognitive function

›Pupil size and reactivity — miosis vs. mydriasis for toxidrome identification

›Focal neurological deficits — localization for structural pathology

›Gait abnormalities

›Abnormal movements — tardive dyskinesia, extrapyramidal signs

Psychiatric mental status examination

›Formal mental status components

›Appearance and behavior — dishevelment, guarding, agitation level

›Speech — rate, volume, pressured quality suggesting mania

›Mood and affect — dysphoric, euphoric, labile, flat

›Thought process — tangential, loosely associated, disorganized

04Differential Diagnosis/ddx38

Primary psychiatric etiologies

›Psychotic disorders

›Schizophrenia — ICD-10 F20; OR approximately 11x increased violence risk

›Schizoaffective disorder — ICD-10 F25; OR approximately 18x increased violence risk

›Brief psychotic disorder — ICD-10 F23

›Delusional disorder — ICD-10 F22; persecutory subtype highest risk

›Mood disorders

›Bipolar disorder manic or mixed episode — ICD-10 F31; grandiosity and impulsivity

›Major depressive disorder with psychotic features — ICD-10 F32.3

›Personality disorders

›Antisocial personality disorder — ICD-10 F60.2; OR approximately 24x increased violence risk

›Borderline personality disorder — ICD-10 F60.3; OR approximately 16x increased violence risk

›Paranoid personality disorder — ICD-10 F60.0; OR approximately 15x increased violence risk

Substance-related etiologies

›Intoxication states

›Stimulant intoxication: methamphetamine, cocaine — ICD-10 F15.1x

›PCP intoxication — ICD-10 F16.1x; extreme agitation and violence

›Alcohol intoxication — ICD-10 F10.1x; disinhibition mechanism

›Synthetic cannabinoid intoxication — acute psychosis and aggression

›Hallucinogen intoxication — ICD-10 F16.1x

›Withdrawal states

›Alcohol withdrawal — ICD-10 F10.3x; seizure and delirium risk

›Benzodiazepine withdrawal — ICD-10 F13.3x

Medical and neurological etiologies

›Delirium

›ICD-10 F05; must be excluded before attributing to primary psychiatric illness

›Medical, metabolic, infectious, or toxic etiologies

›Neurological conditions

05Laboratory Tests/lt36

Targeted metabolic testing

›Blood glucose

›Hypoglycemia mimics psychiatric emergency — point-of-care testing immediately

›Threshold: blood glucose less than 3.9 mmol/l requires immediate treatment

›ACEP Clinical Policy 2017 does not recommend routine labs but supports targeted testing

›Basic metabolic panel

›Sodium, potassium, chloride, bicarbonate for electrolyte abnormalities

›Creatinine and urea for renal function

›If delirium suspected: comprehensive metabolic panel with LFTs

›Thyroid function tests

›TSH if new-onset psychosis or mood symptoms without prior diagnosis

›Free T4 if TSH abnormal

Toxicology screening

›Urine drug screen

›Essential to identify substance-related etiologies of HI

›Immunoassay panels vary by institution; confirm with laboratory

›Synthetic cannabinoids and newer designer drugs may not appear on standard panels

›False positives: quinolones for opiates; decongestants for amphetamines

›Blood alcohol level

›Quantitative ethanol level — correlate with clinical presentation

›Clinical intoxication can occur at varying blood levels depending on tolerance

›Serum drug levels

›If prescribed antipsychotic or mood stabilizer: consider serum level to assess adherence

›Lithium level if prescribed — toxicity can cause CNS dysfunction and aggression

Infection and hematology screening

›Complete blood count

›Leukocytosis suggesting infection as cause of delirium

›Anemia contributing to altered mental status

06Diagnostic Tests/dt44

Scoring Systems

›Violence risk assessment tools

›Historical Clinical Risk Management-20 (HCR-20) — structured professional judgment tool

›Evaluates historical, clinical, and risk management domains

›Not validated for real-time ED use; used by forensic psychiatry

›Oxford Mental Illness and Violence (OxMIV) tool

›Validated for violence risk in severe mental illness

›Evaluates suicide and violence risk simultaneously

›Brondset Violence Checklist (BVC)

›6-item tool designed for inpatient short-term violence prediction

›Confusion, irritability, boisterousness, physical threats, verbal threats, attacking objects

›STAMP tool for agitation screening

›Staring, tone of voice, anxiety, mumbling, pacing

›Identifies pre-escalation behavioral cues for early intervention

›Columbia Suicide Severity Rating Scale (C-SSRS)

›Applied to concurrent suicidal ideation — 67-77% co-occurrence with HI

›Stratifies passive ideation vs. active ideation with plan and intent

MRI

›MRI brain indications in homicidal ideation

›New-onset psychosis without prior psychiatric history

›Structural lesion must be excluded: tumor, demyelination, encephalitis

›Focal neurological deficits on examination

›Seizure disorder on differential

›Suspected autoimmune encephalitis

›FLAIR and DWI sequences for limbic involvement

›Anti-NMDA receptor encephalitis can present with psychiatric emergency and aggression

›Suspected neurosyphilis or HIV encephalopathy

›Protocol consideration

07Disposition/dispo29

Admission indications

›Criteria for psychiatric inpatient admission

›Specific, credible threat with identified target and organized plan

›Active psychosis with command hallucinations directing harm

›Inability to contract for safety or cooperate with outpatient safety plan

›Concurrent high-risk suicidal ideation with plan or intent

›Acute intoxication with persistent HI after sobering

›No adequate outpatient support or confirmed follow-up

›Involuntary hold initiation if criteria met and patient refuses voluntary admission

Observation placement

›Criteria for ED observation

›Substance-related HI that may resolve with sobriety — reassess after 4-6 hours

›Vague or passive ideation without plan pending formal psychiatric evaluation

›Medical workup incomplete and medical etiology must be excluded

Discharge criteria

›Safe discharge requirements

›Fleeting, ego-dystonic thoughts without plan, identified target, or intent to act

›Strong protective factors: social support, active engagement in treatment, no access to means

›Reliable outpatient psychiatric follow-up confirmed within 24-72 hours

›Lethal means counseling completed and documented

›Safety planning completed with patient and support person

›Written crisis plan provided including emergency contacts and crisis hotline numbers

Transfer criteria

›Interfacility transfer indications

›No psychiatric beds available at presenting facility

›Forensic psychiatric evaluation required

›Medically complex patient requiring higher level of psychiatric care

›Transfer documentation: risk assessment, clinical reasoning, legal status, medications given

08Treatment/t67

De-escalation

›Verbal and environmental de-escalation

›First-line approach for all agitated patients before pharmacotherapy

›Low-stimulus environment: reduce noise, lighting, crowding

›Calm, non-confrontational communication with clear limits

›Offer oral medication as show of respect and to build therapeutic alliance

›Evidence: Cochrane review (Spencer 2018) supports structured de-escalation for non-psychosis-induced aggression

Rapid tranquilization — oral

›First-line oral agents

›Olanzapine oral

›Dose: 5-10 mg orally

›Onset: 15-45 minutes

›Preferred in psychosis-related agitation

›Lorazepam oral

›Dose: 1-2 mg orally

›Use with caution in elderly and brain-injured patients — paradoxical disinhibition risk

›Haloperidol oral combined with lorazepam

›Haloperidol 5 mg plus lorazepam 2 mg orally

›Alternative when olanzapine not available

Rapid tranquilization — intramuscular

›First-line IM agents

›Olanzapine IM

›Dose: 10 mg IM

›Do NOT combine with IM benzodiazepine — risk of cardiorespiratory depression

›Preferred for psychosis-related agitation

›Haloperidol IM with promethazine

›Haloperidol 5 mg IM plus promethazine 25-50 mg IM

›Promethazine reduces extrapyramidal side effects and adds sedation

›Droperidol IM

›Dose: 5-10 mg IM

›QTc prolongation risk — obtain ECG if repeated dosing

›Second-line and rescue IM agents

›Midazolam IM

›Dose: 5 mg IM

›Fastest onset of available IM agents

›Risk of respiratory depression — have resuscitation equipment available

›Ketamine IM

›Dose: 2-5 mg/kg IM for severe agitation refractory to first-line agents

›Risk of laryngospasm and emergence reactions

›Reserve for life-threatening excited delirium

Lethal means restriction

›Firearm and weapon counseling

›Assess access to firearms, weapons, and potentially lethal medications

›Counsel family on securing or removing firearms from home

›Extreme Risk Protection Orders (ERPOs) available in applicable jurisdictions

›Firearm access is an independent risk factor for completed violence

›NEJM 2024: Clinical approaches to firearm injury prevention support ED-based counseling

Treatment of underlying psychiatric condition

›Disorder-specific pharmacotherapy

›Schizophrenia or acute psychosis

›Antipsychotic initiation or restart if non-adherent

›Long-acting injectable antipsychotic consideration for adherence-related relapse

›VA/DoD CPG 2023: supports antipsychotic therapy for first-episode psychosis

›Bipolar disorder manic episode

›Mood stabilizer initiation: lithium or valproate

›Antipsychotic adjunct for acute mania with psychotic features

›VA/DoD CPG 2023 for bipolar disorder supports combined therapy

›Substance intoxication

›Supportive care and monitoring during sobering period

›Reassess HI after intoxication resolves

›Delirium

›Identify and treat underlying medical cause

›Low-dose haloperidol for agitation if required

›Personality disorder crisis

›Crisis intervention and safety planning

›Outpatient DBT or CBT referral on discharge

Physical restraints

›Restraint protocol

›Last resort only when less restrictive measures have failed

›APA 2022: continuous monitoring required during physical restraint

›Supine position with head elevated to reduce asphyxiation risk

›Reassess restraint necessity at regular intervals

›Document clinical indication and ongoing reassessment

09Special Populations/sp47

Pregnancy

›Physiologic and safety considerations

›Homicidal ideation in pregnancy requires urgent psychiatric consultation

›Perinatal mood and psychotic disorders can present with violence risk

›Avoid benzodiazepines in first trimester — teratogenic risk with prolonged exposure

›Pharmacotherapy in pregnancy

›Haloperidol — FDA category C; relatively more data in pregnancy than newer agents

›Olanzapine — associated with neonatal extrapyramidal symptoms and metabolic effects

›Lorazepam — use only if necessary; neonatal respiratory depression risk

›Valproate — avoid in pregnancy; high teratogenicity and neurodevelopmental harm

›Lithium — category D; Ebstein anomaly risk at higher doses; use with caution

›Special considerations

›Intimate partner violence screening — overlap with perinatal aggression presentations

›Psychiatric inpatient admission preferred over medication escalation when HI is significant

›Neonatology or obstetrics consultation for all pharmacological interventions near delivery

Geriatric

›Age-related risk modifications

›New-onset HI in elderly without prior psychiatric history — medical etiology until proven otherwise

›Delirium is a common cause of agitation and aggression in older adults

›Dementia with behavioral and psychological symptoms — ICD-10 F02.81

›Medication safety in elderly

›Benzodiazepines — Beers Criteria high-risk agents in elderly; paradoxical disinhibition

›Haloperidol — lower doses required; increased sensitivity to extrapyramidal effects

›Olanzapine — FDA black box warning for use in elderly patients with dementia-related psychosis

›Droperidol — QTc prolongation risk is amplified in elderly

›Modified evaluation approach

›Cognitive baseline from collateral — essential for delirium vs. dementia distinction

›Medication review for polypharmacy contributors: steroids, anticholinergics, dopamine agonists

10Background/b56

Epidemiology

›Prevalence and population data

›Homicidal ideation is a recognized psychiatric emergency presentation in EDs worldwide

›Carbone et al. 2020 (Journal of Forensic Sciences): analyzed HI using 2016 Nationwide Emergency Department Sample (NEDS)

›HI-related ED visits: predominantly male, younger patients, with substance use and psychiatric comorbidities

›67-77% of patients presenting with HI also endorse concurrent suicidal ideation

›Psychiatric disorder associations

›Whiting et al. 2021 (Lancet Psychiatry): structured review of violence risk by individual diagnosis

›Antisocial personality disorder: OR approximately 24x increased violence risk vs. general population

›Schizoaffective disorder: OR approximately 18x

›Borderline personality disorder: OR approximately 16x

›Paranoid personality disorder: OR approximately 15x

›Schizophrenia: OR approximately 11x

›Substance use disorders: single most consistent risk factor across studies

›Mortality and outcomes

›Small proportion of HI patients will act on their ideation — majority do not

›Risk is dynamic and modifiable with appropriate treatment and means restriction

›Prognosis favorable in substance-related HI if sobriety achieved

›Prognosis favorable in medication-responsive psychosis with treatment engagement

Pathophysiology

›Neurobiological mechanisms

›Prefrontal cortical dysregulation — impaired impulse control and threat appraisal

›Dopaminergic excess in mesolimbic pathways — paranoid ideation and hypervigilance

›Serotonergic dysfunction — impulsive aggression link in personality disorder populations

›Amygdala hyperreactivity — exaggerated threat response and fear-driven aggression

›Psychotic mechanisms

›Command auditory hallucinations to harm others — direct behavioral driver

›Persecutory delusions — patient believes threat is coming from target; preemptive logic

›Paranoid ideation — threat overperception with lack of insight

›Substance and pharmacological mechanisms

›Stimulants — dopamine and norepinephrine excess; paranoia and disinhibited aggression

›PCP — NMDA receptor antagonism; dissociation and marked agitation

›Alcohol — GABA potentiation with frontal disinhibition

›Paradoxical benzodiazepine reactions — particularly in elderly and brain-injured patients

›Medications contributing to HI or aggression: stimulants, corticosteroids, anticholinergics, dopamine agonists, SSRI-induced akathisia

›Developmental and social mechanisms

›Adverse childhood experiences — trauma exposure alters threat appraisal systems

›Social learning of violence — exposure to domestic violence normalizes aggression

›Biosocial theory in borderline PD — emotional dysregulation with invalidating environments

Therapeutic Considerations

›Risk stratification framework

›APA Resource Document on Violence Risk Assessment (Buchanan 2011) — structured professional judgment

›Static risk factors: history of violence (strongest predictor), male sex, younger age, prior incarcerations

›Dynamic risk factors: current substance use, medication non-adherence, active psychosis, current stressors

›Dynamic factors are modifiable and the primary targets of acute intervention

›Pharmacological agitation management evidence base

›Uribe et al. 2025 (BMC Psychiatry) — umbrella review supporting IM antipsychotics first-line for acute agitation

›Bak et al. 2019 (European Psychiatry) — systematic review supporting combined haloperidol and promethazine

›Kim et al. 2021 (Expert Opinion on Drug Safety) — safety review of rapid tranquilization agents in ED

›Stetson and Osser 2022 (Current Opinion in Psychiatry) — psychopharmacology of agitation in acute psychosis

›Duty to protect legal framework

›Tarasoff v. Regents of University of California (1976) — foundational US case

›Applies in approximately 33 jurisdictions with mandatory or permissive duty to warn provisions

›Boulos et al. 2023 (Journal of Forensic Sciences) — reviewed duty-to-warn jurisprudence variations by state

›Radley and Felthous 2025 — specificity rule in duty to protect post-Maas decision in Pennsylvania

›Means restriction evidence

›Carter and Cunningham 2024 (NEJM) — clinical approaches to prevention of firearm-related injury

›Extreme Risk Protection Orders (ERPOs) reduce firearm access in high-risk individuals

›Lethal means counseling with family is evidence-based component of violence prevention

11Patient Discharge Instructions/pdi32

copy discharge instructions

›What is homicidal ideation

›Homicidal ideation means having thoughts about harming or killing another person

›These thoughts exist on a spectrum from brief, unwanted thoughts to specific plans

›You were evaluated today and determined to be safe for discharge with a safety plan

›Your diagnosis and treatment plan

›Your doctor identified the following concern contributing to your thoughts:

›You have been given the following prescription or medication change if applicable

›It is very important to take your medications exactly as prescribed

›Alcohol and drug use significantly increase the risk of acting on violent thoughts — avoid all substances

›Your safety plan

›Keep your written safety plan with you at all times

›Your emergency contacts are listed in your safety plan

›If you feel your thoughts are getting stronger, call a trusted person before acting

›Remove or secure any firearms or weapons from your home

›Ask a family member or friend to safely store any weapons during this time

›Follow-up appointment

›You have a psychiatry or mental health appointment scheduled within 24-72 hours

›If you cannot make your appointment, call to reschedule immediately

›Do not skip follow-up — this is an important part of your treatment

›Return to emergency department immediately if

›Your thoughts of harming others become stronger or more specific

›You develop a specific plan or target

›You have access to a weapon and feel unable to resist using it

›You feel you cannot keep yourself or others safe

›You develop thoughts of harming yourself

›Your agitation, aggression, or paranoia worsens significantly

›You experience a medication side effect that concerns you

12References/r36

Guidelines and key sources

›ACEP Clinical Policy 2017

›Nazarian DJ et al. Clinical Policy: Critical Issues in the Diagnosis and Management of the Adult Psychiatric Patient in the Emergency Department. Annals of Emergency Medicine. 2017

›Supports targeted laboratory testing based on clinical presentation for psychiatric ED patients

›APA Resource Documents

›Buchanan A et al. Psychiatric Violence Risk Assessment. American Psychiatric Association. 2011

›Kapoor R et al. Resource Document on Risk-Based Gun Removal Laws. American Psychiatric Association. 2018

›APA Resource Document on Seclusion or Restraint. American Psychiatric Association. 2022

›VA/DoD Clinical Practice Guidelines

›Arias-Reynoso M et al. Management of First-Episode Psychosis and Schizophrenia (SCZ). Department of Veterans Affairs. 2023

›Abrams T et al. Management of Bipolar Disorder (BD). Department of Veterans Affairs. 2023

Epidemiology and risk assessment studies

›Violence and mental illness epidemiology

›Whiting D, Lichtenstein P, Fazel S. Violence and Mental Disorders: A Structured Review. Lancet Psychiatry. 2021

›Carbone JT et al. Homicidal Ideation and Forensic Psychopathology: Evidence From the 2016 NEDS. Journal of Forensic Sciences. 2020

›Sun CF et al. Homicidal Ideation and Psychiatric Comorbidities in Inpatient Adolescents Aged 12-17. Frontiers in Psychiatry. 2022

›Asnis GM et al. Violence and Homicidal Behaviors in Psychiatric Disorders. Psychiatric Clinics of North America. 1997

›Risk assessment tools

›Beaudry G et al. Evaluating Risk of Suicide and Violence in Severe Mental Illness: OxMIS and OxMIV. Frontiers in Psychiatry. 2022

›Välimäki M et al. Risk Assessment for Aggressive Behaviour in Schizophrenia. Cochrane Database. 2024

Pharmacological management

›Agitation treatment evidence

›Uribe ES et al. Pharmacological Management of Acute Agitation in Psychiatric Patients: Umbrella Review. BMC Psychiatry. 2025

›Bak M et al. Pharmacological Management of Agitated and Aggressive Behaviour: Systematic Review and Meta-Analysis. European Psychiatry. 2019

›Kim HK et al. Safety and Efficacy of Pharmacologic Agents for Rapid Tranquilization in the ED. Expert Opinion on Drug Safety. 2021

›Stetson SR, Osser DN. Psychopharmacology of Agitation in Acute Psychotic and Manic Episodes. Current Opinion in Psychiatry. 2022

›Maniaci MJ et al. Patients Threatening Harm to Others Evaluated Under the Florida Involuntary Hold Act. Southern Medical Journal. 2019

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Reviewed by SymptomDx Medical Team · Last reviewed August 18, 2026

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