A 19-year-old man is brought to the emergency department by his mother due to behavioral changes. She says that he has been acting strangely for the past 2 months, spending significantly less time with his friends and more time on the computer. Over the past few nights, the mother has observed the patient shouting at the computer. She became alarmed when he suddenly disconnected all electronic devices in the house and warned his family that encrypted messages were being sent over the Internet to control his brain. The patient's grades at the local community college have recently declined, and he stopped attending classes after he became convinced that other students were laughing at him behind his back. Medical history is noncontributory. The patient does not use tobacco or alcohol but smokes marijuana daily. He has also used cocaine on several occasions. Family history is significant for schizophrenia in a maternal uncle. Vital signs and physical examination are normal. The patient is cooperative, guarded, and anxious during the interview. Blood work and a CT scan of the head are normal. Urine toxicology is positive for tetrahydrocannabinol. The mother asks if her son is going to be okay. After consent is obtained from the patient to speak with his mother, which of the following is the most appropriate response to her at this time?
Acute-onset psychosis in children & adolescents | |
Cause | Examples |
CNS insults |
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Metabolic/electrolyte |
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Autoimmune |
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Substance use |
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| NMDA = N-methyl-D-aspartate; THC = δ-9-tetrahydrocannabinol. | |
This patient's 2-month history of paranoia, delusions of reference, and social withdrawal is consistent with a psychotic disorder. The possibility of a substance-induced psychotic disorder versus a primary psychotic disorder (eg, schizophreniform disorder, schizophrenia) must always be considered, especially in this patient with daily marijuana and occasional cocaine use.
The relationship between substance use and psychosis is bidirectional, and those with susceptibility to developing a primary psychotic disorder may also have a predisposition toward using substances, accelerating the presentation. Cocaine intoxication and withdrawal can present with acute psychotic symptoms; in addition, daily use of high-potency cannabis (>10% delta-9-tetrahydrocannabinol [THC]) carries a risk for new-onset psychosis with a dose-response relationship. Conversion from cannabis-induced psychotic disorder to a primary psychotic disorder occurs in about 40% of cases, with adolescents and young adults using daily, high-potency cannabis at especially high risk.
Although some features point toward substance-induced psychosis, only prolonged periods of abstinence determine substance-induced psychosis alone versus a primary psychotic disorder (Choice D). Therefore, a diagnosis of primary psychotic disorder should not be made prematurely (Choices A and B). The most appropriate response to this mother is to acknowledge the seriousness of the patient's psychotic symptoms but avoid making a premature definitive diagnosis, given the potential for resolution if this patient has a substance-induced psychosis.
(Choice C) Although this patient's severe presenting symptoms should be managed with an antipsychotic regardless of whether the etiology is substance induced or a primary psychotic disorder, declaring that he has schizophrenia at this point is premature. Patients with concerns of substance-induced psychosis should be stabilized with antipsychotics, when necessary and then gradually tapered off of the medication if possible and under close supervision.
Educational objective:
Active substance use, particularly high-potency, high-frequency cannabis use in adolescents and young adults, obscures the diagnosis in new-onset psychosis. Because symptoms could resolve with abstinence or convert to a primary psychotic disorder (eg, schizophreniform disorder, schizophrenia), physicians should inform the patient and family of the diagnostic possibilities and avoid premature diagnosis or false reassurance.