CASE Grieving, delusional
Mr. M, age 51, is brought to the emergency department (ED) because of new-onset delusions and decreased self-care over the last 2 weeks following the sudden death of his wife. He has become expansive and grandiose, with pressured speech, increased energy, and markedly reduced sleep. Mr. M is preoccupied with the idea that he is “the first to survive a human reboot process” and says that his and his wife’s bodies and brains had been “split apart.” Mr. M has limited his food and fluid intake and lost 15 lb within the past 2 to 3 weeks.
Mr. M has no history of any affective, psychotic, or other major mental disorders or treatment. He reports that he has regularly used Cannabis over the last 10 years, and a few years ago, he started occasionally using nitrous oxide (N2O). He says that in the week following his wife’s death, he used N2O almost daily and in copious amounts. In an attempt to “self-anesthetize” himself after his wife’s funeral, he isolated himself in his bedroom and used escalating amounts of Cannabis and N2O, while continually working on a book about their life together.
At first, Mr. M shows little emotion and describes his situation as “interesting and fascinating.” He mentions that he thinks he might have been “psychotic” the week after his wife’s death, but he shows no sustained insight and immediately relapses into psychotic thinking. Over several hours in the ED, he is tearful and sad about his wife’s death. Mr. M recalls a similar experience of grief after his mother died when he was a teenager, but at that time he did not abuse substances or have psychotic symptoms. He is fully alert, fully oriented, and has no significant deficits of attention or memory.
The authors’ observations
Grief was a precipitating event, but by itself grief cannot explain psychosis. Psychotic depression is a possibility, but Mr. M’s psychotic features are incongruent with his mood. Mania would be a diagnosis of exclusion. Mr. M had no prior history of major affective illness. Mr. M was abusing Cannabis, which might independently contribute to psychosis1; however, he had been using it recreationally for 10 years without psychiatric problems. N2O, however, can cause symptoms consistent with Mr. M’s presentation.
EVALUATION Laboratory tests
Mr. M’s physical examination is notable only for an elevated blood pressure of 196/120 mm Hg. Neurologic examination is normal. Toxicology is positive for cannabinoids and negative for amphetamines, cocaine, opiates, and phencyclidine. Chemistries are normal except for a potassium of 3.4 mEq/L (reference range, 3.7 to 5.2 mEq/L) and a blood urine nitrogen of 25 mg/dL (reference range, 6 to 20 mg/dL), which are consistent with reduced food and fluid intake. Mr. M shows no signs of anemia. Hematocrit is 42% and mean corpuscular volume is 90 fL. Syphilis screen is negative; a head CT scan is unremarkable.
Further workup reveals a cobalamin (vitamin B12) level of 82 pg/mL (reference range, 180 to 900 pg/mL) and a methylmalonic acid level of >5 (reference range, <0.3). Mr. M’s folate level is normal (>22 ng/mL). Because the acute onset of symptoms corresponded with a sudden increase in N2O use, further workup for other causes of vitamin B12 deficiency (Table 12) is not pursued.