A 28-year-old woman is brought to the office by her husband, who is concerned about her recent behavior. For the past 6 months, she has refused to eat any food that is not prepackaged out of fear of becoming ill. The patient has also placed a lock on the cabinet where she keeps her food and refuses to eat in restaurants. Before eating, she examines the food on her plate systematically, carefully checking for any possible contaminants. The patient believes that someone has been poisoning her food; as evidence, she points to a rash on her arms and says she is more fatigued than usual. The patient worries that the rash will spread to other areas and fears that she is developing a slowly progressive illness. She has continued to work but seldom interacts with coworkers. The patient has no psychiatric history. Vital signs are stable. Examination shows a 2.27-kg (5-lb) weight loss since a prior visit 9 months ago, and small, dry, scaling, patchy areas in her elbow creases, consistent with eczema. The patient's mood is anxious and her affect is tense. Which of the following is the most likely diagnosis?
Delusional disorder | |
Clinical features |
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Treatment |
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This patient's history of persistent delusions about being poisoned, in the absence of other prominent psychotic symptoms, is consistent with delusional disorder. Her behavior unrelated to her delusion does not appear to be bizarre or odd, and she is still able to function at work. Delusional disorder may be subtyped based on delusional themes: persecutory (eg, being poisoned, harassed, plotted against), erotomanic (false belief that someone of higher status is in love with them), grandiose (eg, great talent, insights, achievements), jealous (eg, unfaithful partners), and somatic (eg, bodily functions, sensations).
Delusional disorder must be differentiated from other psychotic disorders. Patients with schizophrenia have additional psychotic symptoms (eg, hallucinations, disorganization, negative symptoms) and greater functional deterioration (Choice E).
(Choice B) Patients with illness anxiety disorder experience anxiety with excessive concern and preoccupation about having a serious medical illness, but they do not have delusions. If anxiety about being ill is related to a fixed delusional belief (eg, poisoned food), then delusional disorder is the appropriate diagnosis.
(Choice C) This patient lacks the intrusive obsessions and time-consuming compulsive rituals required for diagnosis of obsessive-compulsive disorder.
(Choices D and F) Personality disorders are characterized by lifelong patterns of behavior beginning in early adulthood; they do not involve delusional beliefs. Paranoid personality disorder involves pervasive distrust and suspiciousness of others. Patients with schizotypal personality disorder exhibit eccentric behavior, which may include suspiciousness or odd beliefs, but their beliefs are not of delusional intensity. This patient has developed delusions over the past 6 months, which represents a change from her baseline.
Educational objective:
Delusional disorder involves one or more delusions and the absence of other prominent psychotic symptoms. Apart from the impact of delusional beliefs, the individual is still able to function.