Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Simrat Sarai, M.D. [2]
Overview
The differential diagnosis of delusional disorder is highly important because the occurrence of delusional thinking has many sources, mostly secondary to other conditions; cases of primary delusional disorder are uncommon. Hence a practical principle is to detect or rule out other possible, usually more common causes, before arriving at the diagnosis [4,20]. These include:
●Medical conditions (table 1)
●Medications (table 2)
●Substance-induced disorders (table 2)
●Other mental disorders, including schizophrenia and mood disorder
The clinical evaluation to rule out other causes of psychosis is described above. (See 'Assessment' above.)
Distinguishing features of delusional disorder include the absence of medical illnesses and medications causing psychosis, presence of delusions for at least one month, the absence of other positive symptoms of psychosis (except for hallucinations that are part of the delusional theme), the absence of functional impairment (except that related to the delusional theme), and the absence of overlap (or overlap of a limited duration) between mood symptoms and the delusions [1]. Schizophrenia typically presents with a broader array of positive and negative symptoms and marked functional impairment for at least six months. In bipolar disorder and major depression with psychotic features, delusional thinking is typically accompanied by mania or depression. An algorithm (algorithm 1) depicts the differential diagnosis of delusional disorder.
The differential diagnosis of psychosis is discussed in greater detail separately.
Delusional symptoms are preferentially associated with disorders involving the limbic system and basal ganglia.[4]
Fifty percent of patients with Huntington disease and individuals with idiopathic basal ganglia calcifications developed delusions at some point of their illness.[4]
Head trauma has been associated with development of delusions. Koponen et al[27] found patients with traumatic brain injury were diagnosed with delusional disorder in 5% of the cases during a 30-year follow-up (3 out of 60 assessed patients).
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| Medical Conditions
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Examples
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- Substrate deficiency
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- Hypoglycemia*
- Cerebral hypoxia* causes of cerebral hypoxia include cardiac insufficiency, pulmonary insufficiency, and severe anemia.
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- Neurodegenerative disorders
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- Alzheimer disease
- Pick disease
- Huntington disease
- Parkinson Disease
- Basal ganglia calcification (Fahr disease)
- Multiple sclerosis
- Metachromatic leukodystrophy
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- Vascular disease
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- Atherosclerotic vascular disease, especially when associated with diffuse, temporoparietal, or subcortical lesions
- Hypertensive encephalopathy
- Subarachnoid hemorrhage
- Temporal arteritis
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- Infectious disease
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- Human immunodeficiency virus/acquired immune deficiency syndrome (AIDS)
- Opportunistic infections in AIDS
- Encephalitis lethargica
- Creutzfeldt-Jakob disease
- Syphilis
- Malaria
- Acute viral encephalitis
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- Other CNS disorders
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- Brain tumors, especially temporal lobe and deep hemispheric tumors
- Epilepsy, especially complex partial seizure disorder, temporal lobe epilepsy
- Stroke*
- Brain abscess*
- CNS infection (meningitis, encephalitis)*
- Interictal psychosis
- Head trauma (subdural hematoma)*
- Anoxic brain injury
- Fat embolism
- Brain abscess*
- Landau Kleffner syndrome
- SSPE*
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- Vitamin deficiences
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- Vitamin B-12 deficiency
- Folate deficiency
- Thiamine deficiency
- Niacin deficiency
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- Metabolic disorder
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- Hypercalcemia
- Hyponatremia
- Hypoglycemia
- Uremia
- Hepatic encephalopathy
- Porphyria
- Electrolyte disturbance*Δ
- Hepatic failure*
- Postpartum psychosis*
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- Endocrinopathies
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- Addison disease
- Cushing syndrome
- Hyperthyroidism or hypothyroidism
- Panhypopituitarism
- Hashimoto thyroiditis (Hashimoto encephalopathy)
- Thyroid storm*
- Antiphospholipid syndrome
- Hashimoto thyroiditis (Hashimoto encephalopathy)
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- Medications
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- Analgesics such as meperidine, pentazocine, indomethacin
- Adrenocorticotropic hormones
- Anabolic steroids such as testosterone, methyltestosterone
- Anticholinergics such as atropine, scopolamine
- Antidepressants such as bupropion, others if triggering a manic switch
- Antiepileptics such as zonisamide, other anticonvulsants at high doses
- antimalarial such as mefloquine, chloroquine
- Anti-parkinsonian drugs such as levodopa, selegiline, amantadine, pramipexole, bromocriptine
- Antivirals such as abacavir, efavirenz, nevirapine, acyclovir
- Cardiovascular drugs such as digoxin, disopyramide, propafenone, quinidine
- Corticosteroids such as prednisone, dexamethasone, etc
- Inhalants such as toluene, butane, gasoline
- Interferons such as interferon alfa-2a/2b
- Over-the-counter (OTC) such as dextromethorphan (DXM), diphenhydramine, some decongestants
- Cimetidine
- Antibiotics (eg, cephalosporins, penicillin), disulfiram
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- Toxins
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- Carbon monoxide
- Organophosphates
- Heavy metals (eg, arsenic, manganese, mercury, thallium)
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- Substances
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- Amphetamines
- Cannabinoids such as marijuana, synthetic cannabinoids (ie, "spice"), dronabinol
- Alcohol and sedatives/hypnotics such as alcohol (intoxication or withdrawal), barbiturates and benzodiazepines (particularly withdrawal)
- Cannabis
- Stimulants such as cocaine, amphetamine/methamphetamine, methylphenidate, certain diet pills, "bath salts" (MDPV, mephedrone), MDMA/ecstasy
- Hallucinogens such as LSD, PCP (phencyclidine), ketamine, psilocybin-containing mushrooms, mescaline, synthetic "designer drugs" (eg, 2-CB, "N-Bomb" [25I-NBOMe]) , salvia divinorum
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References