The ‘meth’ epidemic: Managing acute psychosis, agitation, and suicide risk
Methamphetamine-induced psychosis is difficult to differentiate from a primary thought disorder, especially in patients who
show signs of both.
- signs of psychosis, including paranoia, hallucinations, and homicidal thoughts
- neurocognitive changes, including poor attention, impaired verbal memory, and decreased executive functioning.19
Agitation is frequent, and its severity appears to correlate directly with methamphetamine blood levels.20 Violent behavior is common. In 1,016 previous users, 40% of men and 46% of women described difficulty controlling their behavior when under methamphetamine’s influence.18
In acute clinical practice, differentiating a primary thought disorder from methamphetamine-induced psychosis is challenging—especially when a patient shows signs of both.21 Methamphetamine also can contribute profoundly to depressive and anxiety disorders. Users may experience residual psychotic symptoms years after the original abuse ends, particularly when stressed. Their positive and negative symptoms are strikingly similar to those seen in schizophrenia.21
Longitudinal illness course, recent history, collateral information, and laboratory and physical data may all inform clinical presentations and comorbidity.
Emergent Evaluation
Gathering data. Police bring Mr. J, age 22, to the ED after his parents said he talked about killing himself and the mother of his 4-year-old child. Police report that Mr. J’s parents said he and his friends abuse methamphetamine, but no first-hand information is available.
Disheveled and uncooperative, Mr. J threatens to harm ED staff. His speech is pressured, and he appears to be responding to internal stimuli. Vital signs include temperature 37.8° C, pulse rate 105 bpm, blood pressure 140/85 mm Hg, and respiration rate 18 breaths per minute.
Mr. J refuses to provide blood or urine for drug screening or to provide a history to the ED physician. He attempts to walk out and is placed in restraints after he tries to punch the ED security officer.
Options for containing uncooperative and agitated patients such as Mr. J are extremely limited, and the overriding concern with violently intoxicated patients is to minimize damage to self, others, and property. Methamphetamine abusers have a propensity for impulsivity and violence;18 many are brought to the hospital by police and have criminal histories.1 In emergent evaluation, begin by searching patients and their belongings for weapons.
Because laboratory results and patient history are not immediately available, methamphetamine abuse often is not included in the initial differential diagnosis—particularly for patients with pre-existing primary affective or psychotic disorders. It is critical to remember that methamphetamine abuse might be complicating a patient’s psychiatric presentation.
Managing agitation. When agitation is prominent, secure the patient in a quiet room to reduce stimulation. Have on hand adequate staffing and benzodiazepines, antipsychotics, or both.
In theory, using an antipsychotic to control methamphetamine-induced agitation is problematic because synergy between the two agents might adversely affect cardiac function.15 On the other hand, acute treatment of agitation often leads to salutary declines in pulse rate, blood pressure, respiration rate, and body temperature.
Benzodiazepines vs neuroleptics. Evidence for acute treatment of agitation is limited,22 especially when agitation was induced by methamphetamine. A randomized, controlled comparison of lorazepam and droperidol (a neuroleptic not routinely prescribed for psychosis) suggested that droperidol could be used safely to control agitation in ED patients, with methamphetamine toxicity.23 Droperidol provided more rapid and effective sedation than lorazepam.
Droperidol use has decreased dramatically since 2001, however, when the FDA ordered a black-box warning about potential for cardiac dysrhythmias.24-25 After that warning, the American College of Emergency Physicians26 examined the evidence to identify the most effective pharmacologic treatment for agitation of unknown etiology. Its recommendation—felt to represent “moderate” clinical certainty—was monotherapy with either:
- a benzodiazepine (lorazepam or midazolam)
- or a conventional antipsychotic (droperidol or haloperidol).
The level of certainty for combining a benzodiazepine with an antipsychotic was lower. In our experience, psychiatrists tend to favor haloperidol and lorazepam over droperidol and midazolam.
Evidence on treating methamphetamine-induced agitation is limited (Box 2).22-26 Before you prescribe any medication, keep in mind its side effect profile, the patient’s age and physical condition, and the possibility that other substances might be contributing to emergent presentations.
We have repeatedly and effectively treated acutely agitated patients in the ED with haloperidol and lorazepam without observing adverse effects. Psychiatrists generally favor haloperidol and lorazepam over droperidol and midazolam. When a patient can cooperate with treatment, we recommend an ECG to rule out prolonged QTc interval, an uncommon complication. Telemetry and a cardiology consultation are indicated with a QTc interval >450 msec or >25% over previous ECGs, particularly if you plan to continue haloperidol treatment.27
Physical examination. Because methamphetamine use can cause substantial physical morbidity, we recommend a thorough physical exam aimed at identifying its stigmata (Table 2). Look especially for injuries resulting from violence, and test for sexually-transmitted diseases. Drug testing in the ED is essential to diagnosis and for planning treatment (Box 3).28,29
