Acute Psychosis: Comprehensive Guide for US National Paramedic Practice

Overview of Acute Psychosis

Acute psychosis is a medical emergency characterized by a break from reality, manifesting as hallucinations, delusions, disorganized thought/speech, and abnormal motor behavior, requiring immediate assessment to distinguish life-threatening secondary causes from primary psychiatric disorders 1, 2.

Psychosis affects approximately 3% of the general population during their lifetime 3. Unlike delirium, patients with psychosis typically maintain intact consciousness and awareness, though their perception of reality is severely distorted 1, 2.

Anatomy and Pathophysiology

Normal Neuroanatomy

The brain regions involved in reality testing and perception include:

Frontal cortex: Executive function, decision-making, and reality testing
Temporal lobes: Auditory processing and memory integration
Limbic system: Emotional regulation and memory
Dopaminergic pathways: Mesolimbic (reward/motivation), mesocortical (cognition), nigrostriatal (movement), and tuberoinfundibular (prolactin regulation)
Serotonergic pathways: Mood and perception regulation

Pathological Changes in Psychosis

Primary psychosis involves dysregulation of dopamine neurotransmission, particularly hyperactivity in mesolimbic pathways (causing positive symptoms like hallucinations and delusions) and hypoactivity in mesocortical pathways (causing negative symptoms like flat affect and social withdrawal) 4, 5.

Secondary psychosis results from direct brain injury or dysfunction:

Structural lesions (hemorrhage, tumor, trauma) disrupting frontal-temporal circuits 6
Metabolic derangements affecting neurotransmitter synthesis
Infectious/inflammatory processes damaging neural tissue
Toxic exposures altering receptor function 1, 2

Pertinent History and Demographics

High-Risk Demographics

Primary psychosis:

Age: Peak onset 18-25 years (males), 25-35 years (females)
Gender: Males have earlier onset and more severe course
Family history: 10-fold increased risk with first-degree relative
Substance use: Cannabis increases risk 2-4 fold, especially in adolescence

Secondary psychosis:

Older adults (≥65 years): Higher prevalence of medical causes including dementia, stroke, metabolic disorders 2
Substance users: Methamphetamine, cocaine, synthetic cannabinoids, PCP
Immunocompromised: CNS infections (HIV, syphilis, encephalitis)
Recent head trauma or seizures 7

Critical History Elements

MUST obtain from patient/family/bystanders:

Onset and timeline: Sudden (hours) suggests medical/toxic cause; gradual (days-weeks) suggests primary psychiatric disorder 7
Substance use: Recent use, withdrawal, or new medications (especially anticholinergics, corticosteroids, dopamine agonists)
Medical history: Diabetes, thyroid disease, autoimmune disorders, cancer, HIV, syphilis
Psychiatric history: Prior psychotic episodes, hospitalizations, medication adherence
Recent illness: Fever, headache, head injury, seizures, infection symptoms 7
Medication list: Current antipsychotics, mood stabilizers, or recent changes
Trauma history: Recent head injury within 3 months 7

Signs and Symptoms Paramedics Encounter

Major Presenting Features

Positive symptoms (reality distortion):

Hallucinations: Most commonly auditory ("voices"), but visual hallucinations suggest medical cause 7
Delusions: Fixed false beliefs (paranoid, grandiose, somatic, referential)
Disorganized speech: Word salad, tangential, incoherent
Bizarre behavior: Responding to internal stimuli, inappropriate affect

Negative symptoms (diminished function):

Flat affect, social withdrawal, apathy (more common in chronic psychosis)

Behavioral manifestations:

Agitation: Pacing, yelling, threatening
Aggression: Toward self or others
Catatonia: Immobility, posturing, mutism (rare but life-threatening)
Disorganization: Unable to follow commands, poor self-care

Red Flags for Secondary (Medical) Causes

Transport immediately if present 7:

Vital sign abnormalities: Fever (infection, neuroleptic malignant syndrome), tachycardia >120 (toxicity, thyrotoxicosis), severe hypertension (drug toxicity), bradycardia (increased ICP)
Visual hallucinations (more specific for organic causes than auditory)
Altered level of consciousness: Fluctuating awareness, confusion, disorientation
Acute onset (<24 hours) in patient >40 years without psychiatric history
New focal neurologic deficits: Weakness, numbness, speech difficulty, gait abnormality
Severe headache (worst ever, sudden onset)
Recent head trauma
Seizure activity (witnessed or suspected)
Signs of intoxication/withdrawal: Pupil changes, diaphoresis, tremor

Paramedic Assessment Findings

Scene Size-Up and Initial Approach

Safety first:

Request law enforcement if scene unsafe
Maintain exit route, keep distance (6-8 feet initially)
Remove weapons/dangerous objects from environment
Position crew between patient and exit
Use calm, non-threatening body language and tone

Primary Assessment (Early Findings)

ABCDE approach:

Airway: Usually patent unless catatonic or severely altered
Breathing: Rate, pattern (hyperventilation in panic/stimulant use)
Circulation: HR, BP, skin signs (diaphoresis suggests toxicity/withdrawal)
Disability: GCS, pupil response, gross motor function
Exposure: Track marks, signs of trauma, self-harm injuries

Vital signs:

Temperature (fever = infection, NMS; hypothermia = exposure)
HR (tachycardia = stimulants, anticholinergics, thyrotoxicosis)
BP (hypertension = stimulants, pheochromocytoma)
RR (tachypnea = metabolic acidosis, stimulants)
SpO2 (hypoxia can cause confusion/agitation)
Blood glucose (hypoglycemia mimics psychosis)

Secondary Assessment (Detailed Findings)

Mental status examination:

Appearance: Disheveled, bizarre clothing, poor hygiene
Behavior: Agitated, responding to internal stimuli, bizarre movements
Speech: Pressured, disorganized, tangential, mute
Mood/Affect: Flat, inappropriate, labile
Thought process: Disorganized, tangential, flight of ideas
Thought content: Delusions (paranoid, grandiose, somatic), suicidal/homicidal ideation
Perception: Hallucinations (auditory, visual, tactile)
Cognition: Orientation (person, place, time, situation), memory, attention
Insight/Judgment: Poor (denies illness, refuses help)

Neurologic examination:

Pupil size/reactivity (pinpoint = opioids; dilated = stimulants/anticholinergics)
Facial symmetry (stroke)
Grip strength symmetry (focal weakness)
Gait if safe to assess (ataxia, rigidity)
Tremor (withdrawal, Parkinson's, medication side effect)
Rigidity (neuroleptic malignant syndrome, serotonin syndrome)

Physical examination findings:

Skin: Diaphoresis (withdrawal, toxicity), flushing (anticholinergics), track marks (IV drug use), jaundice (hepatic encephalopathy)
Head: Trauma signs, Battle's sign, raccoon eyes
Neck: Stiffness (meningitis), thyromegaly (thyrotoxicosis)
Cardiovascular: Irregular rhythm (arrhythmia from QT prolongation)
Respiratory: Abnormal breath sounds (pneumonia)
Abdomen: Tenderness, distension (metabolic cause)

Late/Deteriorating Findings

Immediate transport if developing:

Decreasing GCS (<13)
New seizure activity
Respiratory depression (RR <10, SpO2 <90%)
Hemodynamic instability (SBP <90 or >180, HR >130)
Hyperthermia (>104°F) with rigidity (NMS, serotonin syndrome)
Violent escalation despite verbal de-escalation
Catatonia with autonomic instability

EMS Management and Treatment

On-Scene Management (Goal: <10 minutes on scene unless requiring prolonged de-escalation)

Step 1: Ensure safety and attempt verbal de-escalation (2-5 minutes)

Introduce yourself calmly, use patient's name
Speak slowly, use simple sentences
Acknowledge patient's distress without agreeing with delusions
Offer help: "I'm here to make sure you're safe"
Avoid arguing about hallucinations/delusions
Give space, avoid sudden movements
Remove bystanders/family if escalating situation

Step 2: Obtain vital signs and blood glucose (1-2 minutes)

Mandatory: BP, HR, RR, SpO2, temperature, blood glucose
If glucose <60 mg/dL: Administer D10W 250 mL IV or D50W 25 g IV (per protocol)
If hypoxic: Apply oxygen to maintain SpO2 >94%

Step 3: Establish IV access if cooperative (1-2 minutes)

18-20g IV in AC or hand
Draw blood if protocol allows (CBC, CMP, toxicology)

Step 4: Determine transport decision

Transport ALL patients with:

First episode of psychosis
Any red flags for medical cause (see above)
Suicidal or homicidal ideation
Inability to care for self
Request from law enforcement/family
Refusal to take prescribed medications

Consider non-transport ONLY if:

Known chronic psychosis with baseline symptoms
No acute medical concerns (normal vitals, glucose, neuro exam)
Patient has immediate access to psychiatric care
Responsible adult present who can monitor
Patient agrees to follow-up within 24 hours
Medical control physician approves
This is rare in practice; default is transport

Step 5: Pharmacologic intervention if severely agitated and dangerous (per medical control)

Indications for chemical restraint:

Imminent danger to self/crew/others
Preventing assessment/treatment of life-threatening condition
Verbal de-escalation failed after reasonable attempt (5-10 minutes)

Medication options (per protocol/medical control):

First-line for undifferentiated agitation 8:

Midazolam 5 mg IM (preferred for rapid sedation, onset 5-10 min) OR
Lorazepam 2 mg IM (onset 15-20 min, longer duration)

If known psychiatric illness:

Haloperidol 5 mg IM (onset 20-30 min) 8
Ziprasidone 20 mg IM (if available, onset 15-30 min, fewer EPS) 8

Combination therapy for severe agitation 8:

Haloperidol 5 mg IM + Lorazepam 2 mg IM (faster sedation than monotherapy)

Avoid:

Droperidol (FDA black box warning for QT prolongation, though evidence suggests safe) 8
Repeat dosing <30 minutes (risk of over-sedation)
IM medications in patients with coagulopathy or on anticoagulants

Step 6: Physical restraints if necessary

Use only when chemical restraint insufficient or unavailable
Apply per protocol (4-point soft restraints)
Never restrain prone (positional asphyxia risk)
Monitor continuously: vitals q5min, airway, circulation to extremities
Document reason, time applied, ongoing monitoring

Transport Management

Positioning:

Supine on stretcher, head elevated 30° if cooperative
Restrained patients: Supine or lateral (never prone)
Suction immediately available

Continuous monitoring:

Cardiac monitor (watch for QT prolongation if antipsychotics given)
Pulse oximetry continuous
Vitals every 5 minutes if sedated, every 15 minutes if stable
Neurologic checks: GCS, pupil response

Ongoing assessment:

Response to medications (sedation level, respiratory depression)
Emergence of new symptoms (seizure, rigidity, fever)
Reassess blood glucose if altered mental status persists

Supportive care:

Maintain IV patency
Oxygen if SpO2 <94%
Cooling measures if hyperthermic (>101°F)
Protect from self-harm

Medication administration during transport:

Repeat sedation only if patient remains dangerous AND >30 minutes since initial dose
Haloperidol 2.5-5 mg IM OR Midazolam 2.5 mg IM (per medical control)
Monitor for respiratory depression (RR <10, SpO2 <90%)

Radio Report to Receiving Facility

Structured SBAR format:

Situation: "Medic [unit] en route with [age]-year-old [gender] with acute psychosis and agitation."

Background:

Chief complaint and onset timeline
Psychiatric history (known diagnosis, medications, recent changes)
Substance use (recent use, withdrawal)
Medical history (relevant conditions)
Recent events (trauma, illness, medication changes)

Assessment:

Vital signs (initial and current)
Blood glucose
Mental status (GCS, orientation, hallucinations, delusions, behavior)
Neurologic findings (pupils, focal deficits, gait)
Physical exam findings (trauma, fever, rigidity)
Medications administered (dose, time, response)
Restraint status

Recommendation:

ETA
Request psychiatric consultation if not already arranged
Request security if patient remains agitated
Request specific room setup (seclusion room, restraints available)

Example: "Medic 5 en route with 28-year-old male with acute psychosis and agitation. Patient has known schizophrenia, stopped taking risperidone 2 weeks ago. Presenting with auditory hallucinations, paranoid delusions, and aggressive behavior toward family. Vitals: BP 145/92, HR 118, RR 22, SpO2 98% RA, temp 98.6°F, glucose 102. GCS 15, oriented to person only. Pupils equal and reactive. No focal deficits. Administered haloperidol 5 mg IM and lorazepam 2 mg IM at 1430 with partial response. Patient in soft restraints, monitored continuously. ETA 8 minutes. Request psychiatric consultation and security at bedside."

Chronic Psychotic Disorders: Maintenance Medications

Patients with chronic schizophrenia or schizoaffective disorder are typically on long-term antipsychotic medications. Knowing these medications helps paramedics understand the patient's baseline, identify medication non-adherence as a trigger, and anticipate side effects.

Common Maintenance Antipsychotics

Second-generation (atypical) antipsychotics (preferred for long-term use due to lower EPS risk) 5, 9:

Risperidone (Risperdal)

Indications: Schizophrenia, schizoaffective disorder, bipolar mania
Mechanism: D2 and 5-HT2A antagonist
Dosing: 2-6 mg/day PO; also available as long-acting injection (Risperdal Consta) q2 weeks
Pharmacokinetics: Onset 1-2 weeks, peak 1-2 hours PO, half-life 20 hours
Pharmacodynamics: Blocks dopamine (reduces positive symptoms) and serotonin (improves negative symptoms, reduces EPS)
Side effects: EPS (dose-dependent), hyperprolactinemia (gynecomastia, amenorrhea), weight gain, orthostatic hypotension
Contraindications: Hypersensitivity, dementia-related psychosis (increased mortality risk)

Olanzapine (Zyprexa)

Indications: Schizophrenia, bipolar disorder, agitation (IM formulation)
Mechanism: D2, 5-HT2A, H1, M1 antagonist
Dosing: 10-20 mg/day PO; 10 mg IM for acute agitation
Pharmacokinetics: Onset 1-2 weeks, peak 5-8 hours PO, half-life 30 hours
Pharmacodynamics: Broad receptor blockade reduces positive/negative symptoms
Side effects: Significant weight gain and metabolic syndrome (diabetes, hyperlipidemia), sedation, anticholinergic effects
Contraindications: Hypersensitivity, dementia-related psychosis
Paramedic note: Patients may be on concurrent metformin to mitigate metabolic effects 5

Quetiapine (Seroquel)

Indications: Schizophrenia, bipolar disorder, major depression (adjunct)
Mechanism: D2, 5-HT2A, H1 antagonist
Dosing: 300-800 mg/day PO (divided doses)
Pharmacokinetics: Onset 1-2 weeks, peak 1.5 hours, half-life 6 hours
Pharmacodynamics: Lower D2 affinity = fewer EPS, more sedation
Side effects: Sedation, orthostatic hypotension, weight gain, QT prolongation (high doses)
Contraindications: Hypersensitivity, dementia-related psychosis

Aripiprazole (Abilify)

Indications: Schizophrenia, bipolar disorder, major depression (adjunct)
Mechanism: D2 partial agonist, 5-HT2A antagonist
Dosing: 10-30 mg/day PO; also available as long-acting injection (Abilify Maintena) monthly
Pharmacokinetics: Onset 1-2 weeks, peak 3-5 hours, half-life 75 hours
Pharmacodynamics: Partial agonism stabilizes dopamine (not full blockade) = fewer EPS, less weight gain
Side effects: Akathisia (restlessness), insomnia, nausea, minimal weight gain
Contraindications: Hypersensitivity, dementia-related psychosis

Clozapine (Clozaril)

Indications: Treatment-resistant schizophrenia (failed ≥2 antipsychotics), high suicide risk, persistent aggression 9
Mechanism: D2, D4, 5-HT2A, M1, H1 antagonist
Dosing: 300-600 mg/day PO (requires slow titration)
Pharmacokinetics: Onset 2-4 weeks, peak 2.5 hours, half-life 12 hours
Pharmacodynamics: Most effective antipsychotic but highest risk profile
Side effects: Agranulocytosis (1-2%, requires weekly CBC monitoring), seizures (dose-dependent), myocarditis, weight gain, hypersalivation, sedation, constipation (can cause ileus)
Contraindications: History of clozapine-induced agranulocytosis, uncontrolled epilepsy, severe cardiac disease
Paramedic note: Patients on clozapine require weekly blood draws; non-adherence to monitoring can result in medication discontinuation and relapse

First-generation (typical) antipsychotics (less commonly used for maintenance due to higher EPS risk):

Haloperidol (Haldol)

Indications: Schizophrenia, acute agitation, Tourette syndrome
Mechanism: High-potency D2 antagonist
Dosing: 5-20 mg/day PO; 2-10 mg IM for acute agitation; also available as long-acting injection (Haldol Decanoate) monthly
Pharmacokinetics: Onset 3-5 days PO, 20-30 min IM, half-life 18 hours
Pharmacodynamics: Strong D2 blockade reduces positive symptoms but high EPS risk
Side effects: High EPS risk (dystonia, akathisia, parkinsonism), tardive dyskinesia (long-term), QT prolongation, neuroleptic malignant syndrome (rare)
Contraindications: Parkinson's disease, severe CNS depression, coma

Long-Acting Injectable (LAI) Antipsychotics

Why used: Improve adherence in patients with history of non-compliance 9

Common LAIs:

Risperidone (Risperdal Consta): 25-50 mg IM q2 weeks
Paliperidone (Invega Sustenna): 117-234 mg IM monthly
Aripiprazole (Abilify Maintena): 400 mg IM monthly
Haloperidol decanoate: 50-200 mg IM monthly

Paramedic note: Patients on LAIs may still experience relapse if doses missed or medication wears off before next injection.

Adjunct Medications

Benzodiazepines (for anxiety, agitation, insomnia):

Lorazepam (Ativan) 1-2 mg PO/IM BID-TID
Clonazepam (Klonopin) 0.5-2 mg PO BID

Anticholinergics (for EPS from antipsychotics):

Benztropine (Cogentin) 1-2 mg PO/IM BID
Diphenhydramine (Benadryl) 25-50 mg PO/IM TID

Mood stabilizers (for schizoaffective disorder):

Lithium 900-1200 mg/day PO
Valproic acid (Depakote) 750-2000 mg/day PO

Antidepressants (for schizoaffective disorder, depression):

SSRIs (sertraline, fluoxetine)

Metformin (to prevent metabolic syndrome from atypical antipsychotics):

500-1000 mg PO BID 5

Complications of Untreated Acute Psychosis

Immediate Complications (Hours to Days)

Self-harm and suicide:

4-10% of patients with schizophrenia die by suicide 9
Risk highest in young males, early course of illness, during acute episodes
Command hallucinations ("voices telling me to hurt myself") increase risk

Violence toward others:

Risk factors: Paranoid delusions, command hallucinations, substance use, medication non-adherence
Legal consequences (arrest, incarceration)

Accidental injury:

Disorganized behavior leading to falls, motor vehicle accidents, exposure to elements
Wandering into traffic, unsafe environments

Substance use complications:

Overdose (intentional or accidental)
Withdrawal syndromes (alcohol, benzodiazepines)
Trauma from intoxication

Medical deterioration:

Failure to recognize/report serious medical symptoms (chest pain, infection)
Dehydration, malnutrition from disorganization
Hyperthermia from agitation in hot environment

Short-Term Complications (Days to Weeks)

Neuroleptic malignant syndrome (NMS):

Mechanism: Severe D2 blockade causing autonomic instability
Presentation: Hyperthermia (>104°F), severe rigidity ("lead pipe"), altered mental status, autonomic instability (tachycardia, labile BP, diaphoresis)
Labs: Elevated CK (>1000), leukocytosis, myoglobinuria
Mortality: 10-20% if untreated
Treatment: Stop antipsychotic, supportive care (cooling, IV fluids), dantrolene, bromocriptine
Paramedic recognition: Fever + rigidity + recent antipsychotic use = NMS until proven otherwise

Serotonin syndrome:

Mechanism: Excess serotonin from drug interactions (antipsychotics + SSRIs + other serotonergic drugs)
Presentation: Hyperthermia, agitation, tremor, hyperreflexia, clonus, diarrhea
Treatment: Stop offending agents, supportive care, cyproheptadine
Paramedic recognition: Hyperreflexia and clonus distinguish from NMS

Acute dystonia:

Mechanism: D2 blockade in nigrostriatal pathway
Presentation: Sudden muscle spasms (neck, jaw, eyes, back), oculogyric crisis (eyes rolled back), torticollis, opisthotonus
Onset: Hours to days after antipsychotic initiation or dose increase
Treatment: Benztropine 1-2 mg IM or diphenhydramine 25-50 mg IM (rapid relief)
Paramedic recognition: Painful, frightening for patient; treat immediately

Akathisia:

Mechanism: D2 blockade causing subjective restlessness
Presentation: Inability to sit still, pacing, leg movements, inner sense of restlessness
Treatment: Reduce antipsychotic dose, add beta-blocker (propranolol) or benzodiazepine

QT prolongation and arrhythmia:

Mechanism: Antipsychotics block cardiac potassium channels
Risk factors: High doses, drug interactions, electrolyte abnormalities (hypokalemia, hypomagnesemia)
Presentation: Palpitations, syncope, sudden cardiac death (torsades de pointes)
Paramedic recognition: Monitor ECG if antipsychotics given; QTc >500 ms = high risk

Long-Term Complications (Months to Years)

Chronic disability:

Persistent positive symptoms (hallucinations, delusions)
Negative symptoms (social withdrawal, apathy, flat affect)
Cognitive impairment (memory, attention, executive function)
Inability to work, maintain relationships, live independently

Tardive dyskinesia (TD):

Mechanism: Chronic D2 blockade causing receptor upregulation
Presentation: Involuntary movements (tongue protrusion, lip smacking, facial grimacing, choreoathetoid limb movements)
Onset: After months to years of antipsychotic use
Risk factors: Older age, female gender, diabetes, first-generation antipsychotics
Treatment: Often irreversible; switch to clozapine or add VMAT2 inhibitor (valbenazine)

Metabolic syndrome:

Mechanism: Atypical antipsychotics (especially olanzapine, clozapine) cause weight gain, insulin resistance
Presentation: Obesity, diabetes, hyperlipidemia, hypertension
Complications: Cardiovascular disease, stroke, premature death
Prevention: Metformin, lifestyle modification, monitoring 5

Increased mortality:

Life expectancy reduced by 15-20 years 9
Causes: Suicide, cardiovascular disease, diabetes, respiratory disease, accidents
Contributing factors: Medication side effects, poor health maintenance, smoking, substance use, healthcare disparities

Social consequences:

Homelessness (20-30% of homeless have severe mental illness)
Incarceration (psychosis misinterpreted as criminal behavior)
Loss of custody of children
Social isolation, loss of support network

Key Paramedic Takeaways

Safety first: Assess scene, request law enforcement if needed, maintain exit route
Rule out medical causes: Check vitals, glucose, neurologic exam; transport if any red flags
Verbal de-escalation is first-line: Calm tone, simple language, acknowledge distress
Chemical restraint only when necessary: Midazolam or lorazepam for undifferentiated agitation; haloperidol for known psychiatric illness 8
Monitor continuously: Vitals q5min if sedated, watch for respiratory depression, NMS, dystonia
Know maintenance medications: Helps identify non-adherence as trigger and anticipate side effects
Transport is default: First episode, medical red flags, suicidal/homicidal ideation, inability to care for self
Structured radio report: SBAR format with psychiatric history, medications given, restraint status

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