Cases That Test Your Skills

The skinny on one patient’s psychosis

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Diet pills purchased online appear to be making Ms. P paranoid, but routine urine screens are negative. What’s causing her delusional episodes?



Presentation: ‘they’re stalking me’

Ms. P, age 30, fears she is being stalked and is too terrified to be home alone. Worried, her ex-boyfriend calls police, who bring her to the emergency room

At the ER, Ms. P reports that surveillance cameras have been planted inside her house, that men often stand on her roof and watch her go to her car, and that men constantly are stalking her. She also hears voices and reports frightening peripheral visions of “outsiders.” The ER doctor consults the psychiatry service and orders laboratory tests, but all results—including urine drug screen findings—are negative.

Ms. P says she has been sleeping 3 to 4 hours nightly. She acknowledges depressed mood and decreased appetite, leading to a 10-lb weight loss over 1 month. She says she has felt depressed off and on for several years but has received no treatment for her mood symptoms. We admit her to the psychiatric unit to treat her acute-onset psychosis.

Lately, Ms. P’s life has been difficult. A college sophomore, she is failing all her classes. She was recently fired from her job as a case manager because of inappropriate behavior, such as buying gifts for the children she was managing and taking them for hair-cuts without their parents’ permission. Several months ago, she broke up with her boyfriend of 6 years. In addition to these stressors, she recently moved into an apartment and for the first time was living on her own.

Medical history. Ms. P has no major medical problems. Her mother has battled alcohol and drug dependence and depression but to Ms. P’s knowledge has never experienced psychosis. Ms. P, who admits that she binge drinks once or twice monthly, meets DSM-IV-TR criteria for alcohol abuse disorder. She denies using illicit drugs but admits that she regularly takes “energy pills” purchased over the Internet because she cannot wake up without them.

Physical exam is normal, but Ms. P’s body mass index (BMI) is 18 kg/m2, slightly below normal (height: 5 feet 8 inches; weight: 117.5 lb).

The authors’ observations

We diagnosed Ms. P as having recurrent and severe major depressive disorder with psychotic features because of her longstanding depressive symptoms. We considered substance-induced psychosis, but her urine drug screen is negative.

Treatment at this point should address both the paranoid delusions and depressive symptoms.

Treatment: starved for energy

We start haloperidol, 1 mg nightly, to treat Ms. P’s paranoid delusions, and mirtazapine, 15 mg nightly, to improve her sleep. We choose mirtazapine—which can increase appetite and lead to weight gain—because Ms. P is underweight. We also choose haloperidol because Ms. P is unemployed and cannot afford a second-generation antipsychotic.

Shortly afterward, we interview Ms. P’s ex-boyfriend. He tells us that she has been using diet pills regularly for 3 to 4 years, and that her chronic use has been escalating by the month. Lately, he says, she has been “popping the pills like candy.”

When we ask Ms. P about her diet pill use, she says she had mainly been using Xenadrine, an over-the-counter weight-loss supplement. Five months ago, she also started taking prescription phentermine, which she purchases over the Internet. She says that before her hospitalization, she was taking three phentermine tablets daily to boost her energy.

According to her ex-boyfriend, Ms. P began showing signs of psychosis 3 to 4 weeks after starting phentermine, and Ms. P notes that her initial paranoia and gustatory hallucinations have worsened. She now fears her bathroom is rigged with cameras. She showers with her swimsuit on.

We change Ms. P’s diagnosis to diet pill-induced psychosis. Because she had discarded the pill packaging before admission, we could not examine it for dosing information or ingredients.

The authors’ observations

Differentiating drug-induced psychosis from other psychoses often is difficult. Mood disorder with psychosis, schizophrenia, and substance-induced psychosis have similar characteristics (Table).

Ms. P has no personal or family history of psychosis that would suggest a thought disorder. She had good pre-morbid functioning (going to college, steady employment, long-term relationship with boyfriend) before her psychosis onset. She did, however, have a personal and family history of depression and was confronting many stressors (losing her job, failing grades at school, breaking up with her longtime boyfriend) that would suggest a primary mood disorder with psychosis.

We suspected an eating disorder and asked Ms. P more than once about her eating habits, but she insists she does not take the pills to lose weight. Also, her ex-boyfriend believes she is eating normally. Her low BMI and suspected obsession with weight loss could have signaled anorexia nervosa, but no other signs were present and her history does not support the diagnosis.

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