• Users Online: 750
  • Home
  • Print this page
  • Email this page
Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Contacts Login 

 Table of Contents  
Year : 2023  |  Volume : 43  |  Issue : 2  |  Page : 79-83

Lurasidone treatment for delusional infestation in a patient with dementia

1 Department of Psychiatry, School of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
2 Department of Psychiatry, School of Medicine, Tri-Service General Hospital, National Defense Medical Center; Student Counseling Center, National Defense Medical Center, Taipei, Taiwan

Date of Submission10-Dec-2020
Date of Decision15-Nov-2021
Date of Acceptance11-Feb-2022
Date of Web Publication25-May-2022

Correspondence Address:
Dr. Nian-Sheng Tzeng
Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, No. 325, Sec. 2, Chenggong Rd., Neihu Dist., Taipei 114
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jmedsci.jmedsci_410_20

Rights and Permissions

Delusional infestation has been described since 1894. The variety of treatments of delusional infestation has been administered in different atypical antipsychotic agents. Here, we present a case of first treatment with lurasidone on the delusional infestation in a 68-year-old female with vascular dementia, and the literature reviews of the related delusion infestation management.

Keywords: Lurasidone, delusional infestation, dementia

How to cite this article:
Her YN, Chang HA, Wan FJ, Tzeng NS. Lurasidone treatment for delusional infestation in a patient with dementia. J Med Sci 2023;43:79-83

How to cite this URL:
Her YN, Chang HA, Wan FJ, Tzeng NS. Lurasidone treatment for delusional infestation in a patient with dementia. J Med Sci [serial online] 2023 [cited 2023 Jun 9];43:79-83. Available from: https://www.jmedscindmc.com/text.asp?2023/43/2/79/346039

  Introduction Top

Psychotic symptoms such as delusions and hallucinations are frequently found in dementia.[1] The delusional infestation, which is also known as delusional parasitosis, has been described in medical literature since 1894, which was defined as a syndrome in which there is a fixed, false belief that one is infested with pathogens despite the absence of medical evidence.[2] Lurasidone is widely used in the treatment of psychotic and mood disorders.[3] However, there are no available studies for the effects of lurasidone in delusional infestations or other psychotic symptoms of patients with dementia.[4] Here, we report a case of a dementia-related delusional infestation of a snake that was successfully treated by lurasidone.

  Case Report Top

A 68-year-old female patient, without medical, personal, or family history of mental illness, except vascular dementia, was sent to the geropsychiatric outpatient department for her fixed delusional belief about “a snake that lives in my body,” and psychomotor agitation. Her first episode of the delusion of snake infestation can be traced back to 3 years ago, when she received a major operation of the left jaw osteonecrosis under general anesthesia, and experienced spontaneous remission after 3 weeks. In this case, her mood symptoms are just secondary to delusional infestation, such as worry and anxiety. There is no significant impairment in attention and not fluctuated throughout the day. In addition, physical examinations, imaging examinations, and laboratory examinations were also arranged, which revealed the case has no other active medical and surgical diseases.

Then, the delusion of snake infestation, on and off over 2 years, and which was spontaneously resolved within 2 weeks. Besides, she presented a series of episodes of declining recent memory and was diagnosed with vascular dementia 14 months before this visit in a neurology department. A structural brain computerized tomogram revealed senile changes with cortical atrophy over the bilateral frontotemporal regions and chronic periventricular white matter ischemic change. The laboratory workup, including the glucose level, renal and liver function tests, serologic tests for syphilis, vitamin B-12 and red blood cell folate levels, and thyroid function tests, only found low-level folic acid (4.2 ng/mL). At first, she was receiving treatment with piracetam 1200 mg/day and folic acid 5 mg/day for disturbance behaviors and subjective distress due to the persistent delusional infestation for 1 month in the neurology department. For the cognitive function tests, the score of Mini-Mental Status Examination (MMSE) was 16 and the Clinical Dementia Rating (CDR) scale was 1.0, which showed recently cognitive function rapid deterioration (the MMSE score decreased from 20 points to 16 points compared with 1 month ago).

She had no obvious response to persistent management among cognitive enhancer such as piracetam and folic acid supplement for 2 months. Then, she was sent to the geropsychiatric outpatient department under the circumstance of marked subjective distress due to the delusional infestation for 3 months, and additionally, she also suffered from auditory hallucinations with a voice discussing “about the snake,” persecutory delusion, and delusional of being under surveillance. Among contemporary antipsychotic drugs, lurasidone has a relatively well-tolerated side effect profile, with low propensity for sedation, cardiac arrhythmia, weight gain, and lipid-related adverse effects.[5],[6] The patient had a history of constipation for long time and had falling down several times, so we chose this lurasidone for its low side effect profile. Lurasidone 20 mg/day was initiated for the patient and titrates to 40 mg/day after 2 weeks. After 4 weeks of treatment, the delusion of the snake infestation subsided, and we increased the lurasidone dosage to 80 mg/day for the persistent auditory hallucinations. After 1 month of lurasidone treatment with 80 mg/day, the psychotic, including the auditory hallucinations symptoms of delusional infestation, became fairly controlled, but the extrapyramidal side effects (EPSE) such as rigidity was found. Therefore, we gradually tapered the lurasidone dosage to 40 mg/day, and then 20 mg/day in the following 3 months for maintenance treatment, and then the delusion of snake infestation and EPSE disappeared. The patient's drug compliance was assured by her son, the major caregiver. The follow-up outpatient clinics in the following 3 years found that although the test scores (MMSE and CDR) did not change, the patient and her family reported that the memory of the patient had slightly improved. Perhaps the improvement was not large, so the test scores did not change.

  Discussion Top

There were several researches about the delusions in the cultural or subculture milieu related to snakes.[7] However, in previous studies, patients with delusional infestation often falsely believed that they were “infested” by parasites or insects.[8] This is a rare case of the patient falsely believing that there was a snake, instead of parasites or insects, in her body. Some previous reports have shown that the patients with delusional parasitosis are concomitant with tactile hallucinations,[9],[10] but in this case, there were no tactile hallucinations, and the underlying reasons are not clear. In addition, delusional infestations are rarely seen in patients with dementia and prior studies are limited.[11],[12],[13],[14],[15] Furthermore, the patients with delusional infections might injure themselves in attempts to be rid of the “parasites,” resulting skin damages, as well as damage caused from using chemical substances and obsessive cleaning routines.[16],[17] However, there was no self-harmful behavior in this case.

In this case, we presumed that the effects of lurasidone on the delusional infestation by the temporal relationship. Previously, several case reports have suggested that delusional infestation best responds to atypical antipsychotics, such as olanzapine,[18],[19],[20] risperidone,[21] aripiprazole,[11],[16],[22],[23],[24 quetiapine,[21] blonanserin,[25] or ziprasidone,[24] as listed in [Table 1]. However, it has also been successfully treated by haloperidol, pimozide, and lurasidone may also have such an effect.
Table 1: Summary of previous studies investigating the use of atypical antipsychotics for the treatment of delusional infestations

Click here to view

Lurasidone, as a second-generation, serotonin-dopamine antagonist, has a favorable safety profile for the young patients with psychotic or mood disorders.[3] One review pointed out that lurasidone is both of reasonable safety and efficacious in the acute and maintenance treatment for the elderly patients with bipolar disorders.[26] In addition, a study found that lurasidone, in the treatment for a patient with schizophrenia, showed improvement in the Measurement and Treatment Research to Improve Cognition in Schizophrenia Consensus Cognitive Battery.[27] This finding hints that lurasidone demonstrates the potential to improve cognition, and hence, could be beneficial for the elderly patients with dementia. As in this case, 3 years of follow-up showed that her cognitive function did not decline anymore, and the memory has improved a little. The prompt relief of EPSE by the decrease of the daily dosage in our case also supports the safety of the usage of lurasidone in the elderly patients with dementia. As with other atypical neuroleptics, lurasidone should be used with caution in the elderly due to an increased risk for a stroke, transient ischemic attack, and mortality compared to placebo,[28],[29],[30] which was caused by atypical antipsychotics that are likely to cause metabolic syndrome. Recent studies on safety and tolerability have shown older adult treatment with lurasidone was associated with minimal effects on weight, lipids, and measures of glycemic control.[31],[32] Most geriatric patients used 60–80 mg/day of lurasidone, which appeared to be efficacious, well-tolerated.[33] Nonetheless, a further study is necessary for the safety profile in these older patients with dementia.

  Conclusion Top

To the best of our knowledge, this is the first case of lurasidone as a successful treatment for delusional infestation. This therapeutic experience should serve as a reminder for the clinicians who are responsible for the care of patients with delusional infestation.

Ethical approval

The Institutional Review Board of the Tri-Service General Hospital, Taipei, Taiwan, as TSGH-IRB No.: C202005108.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal her identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

This study was supported by the Taoyuan Armed Forces General Hospital (TYAFGH-A-110020). The sponsor had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Conflicts of interest

There are no conflicts of interest.

  References Top

Murray PS, Kumar S, Demichele-Sweet MA, Sweet RA. Psychosis in Alzheimer's disease. Biol Psychiatry 2014;75:542-52.  Back to cited text no. 1
Laupland KB, Valiquette L. Delusional infestation. Can J Infect Dis Med Microbiol 2016;2016:9091838.  Back to cited text no. 2
Pompili M, Verzura C, Trovini G, Buscajoni A, Falcone G, Naim S, et al. Lurasidone: Efficacy and safety in the treatment of psychotic and mood disorders. Expert Opin Drug Saf 2018;17:197-205.  Back to cited text no. 3
Tampi RR, Tampi DJ, Balachandran S, Srinivasan S. Antipsychotic use in dementia: A systematic review of benefits and risks from meta-analyses. Ther Adv Chronic Dis 2016;7:229-45.  Back to cited text no. 4
Leucht S, Cipriani A, Spineli L, Mavridis D, Orey D, Richter F, et al. Comparative efficacy and tolerability of 15 antipsychotic drugs in schizophrenia: A multiple-treatments meta-analysis. Lancet 2013;382:951-62.  Back to cited text no. 5
Pharma DS. Lurasidone Demonstrated Efficacy in Treating Patients with Schizophrenia in Pivotal Phase 3 Study”. In: Dainippon Sumitomo Pharma; August 26, 2009. [Last accessed on 2016 Oct 03].  Back to cited text no. 6
Mondal G, Nizamie SH, Mukherjee N, Tikka SK, Jaiswal B. The 'snake' man: Ophidianthropy in a case of schizophrenia, along with literature review. Asian J Psychiatr 2014;12:148-9.  Back to cited text no. 7
Freudenmann RW, Lepping P. Delusional infestation. Clin Microbiol Rev 2009;22:690-732.  Back to cited text no. 8
de Mendonça FJ, Teixeira IA, Marinho V. Ekbom syndrome associated with lewy body dementia: A case report. Dement Neuropsychol 2020;14:83-7.  Back to cited text no. 9
McKinnon AI, Dow R. Brief cognitive behavioural therapy for post-stroke 'delusional infestation' in a 71-year-old man: A single case experimental design. Behav Cogn Psychother 2020;48:717-24.  Back to cited text no. 10
Tzeng NS, Chiang CP. Delusional parasitosis in a patient with brain atrophy and renal failure treated with aripiprazole: Case report. Prog Neuropsychopharmacol Biol Psychiatry 2010;34:1148-9.  Back to cited text no. 11
Le L, Gonski PN. Delusional parasitosis mimicking cutaneous infestation in elderly patients. Med J Aust 2003;179:209-10.  Back to cited text no. 12
Nicolato R, Corrêa H, Romano-Silva MA, Teixeira AL Jr. Delusional parasitosis or Ekbom syndrome: A case series. Gen Hosp Psychiatry 2006;28:85-7.  Back to cited text no. 13
Duggal H, Singh I. Delusional parasitosis as a presenting feature of dementia. J Neuropsychiatry Clin Neurosci 2010;22:123.E11-12.  Back to cited text no. 14
Musso MW, Jones GN, Heck MC, Gouvier D. Delusional parasitosis as a presenting feature of HIV dementia: A case study. Appl Neuropsychol Adult 2013;20:66-72.  Back to cited text no. 15
Yeh TC, Lin YC, Chen LF, Chiang CP, Mao WC, Chang HA, et al. Aripiprazole treatment in a case of amphetamine-induced delusional infestation. Aust N Z J Psychiatry 2014;48:681-2.  Back to cited text no. 16
Tsai SJ, Yeh CB, Wang CW, Mao WC, Yeh TC, Tai YM, et al. Delusional infestation in a patient with posterior reversible encephalopathy syndrome. Aust N Z J Psychiatry 2016;50:1212-3.  Back to cited text no. 17
Howes CF, Sharp C. Delusional infestation in the treatment of ADHD with atomoxetine. BMJ Case Rep 2018;2018:r-226020.  Back to cited text no. 18
Narang T, Singh SM, Kavita. Delusional infestation with fungus. Indian J Dermatol Venereol Leprol 2012;78:645-6.  Back to cited text no. 19
  [Full text]  
Diaz JH, Nesbitt LT Jr. Delusional infestations: Case series, differential diagnoses, and management strategies. J La State Med Soc 2014;166:154-9.  Back to cited text no. 20
Altunay IK, Ates B, Mercan S, Demirci GT, Kayaoglu S. Variable clinical presentations of secondary delusional infestation: An experience of six cases from a psychodermatology clinic. Int J Psychiatry Med 2012;44:335-50.  Back to cited text no. 21
Ponson L, Andersson F, El-Hage W. Neural correlates of delusional infestation responding to aripiprazole monotherapy: A case report. Neuropsychiatr Dis Treat 2015;11:257-61.  Back to cited text no. 22
Rocha FL, Caramelli P, Oliveira LC. Complex visual hallucinations and delusional infestation comorbidity. Arq Neuropsiquiatr 2012;70:553-4.  Back to cited text no. 23
Freudenmann RW, Kölle M, Huwe A, Luster M, Reske SN, Huber M, et al. Delusional infestation: Neural correlates and antipsychotic therapy investigated by multimodal neuroimaging. Prog Neuropsychopharmacol Biol Psychiatry 2010;34:1215-22.  Back to cited text no. 24
Bhatia MS, Rathi A, Jhanjee A. Delusional infestation responding to blonanserin. J Neuropsychiatry Clin Neurosci 2013;25:E54.  Back to cited text no. 25
Vasudev A, Chaudhari S, Sethi R, Fu R, Sandieson RM, Forester BP. A review of the pharmacological and clinical profile of newer atypical antipsychotics as treatments for bipolar disorder: Considerations for use in older patients. Drugs Aging 2018;35:887-95.  Back to cited text no. 26
Harvey PD, Ogasa M, Cucchiaro J, Loebel A, Keefe RS. Performance and interview-based assessments of cognitive change in a randomized, double-blind comparison of lurasidone vs. ziprasidone. Schizophr Res 2011;127:188-94.  Back to cited text no. 27
Herrmann N, Mamdani M, Lanctôt KL. Atypical antipsychotics and risk of cerebrovascular accidents. Am J Psychiatry 2004;161:1113-5.  Back to cited text no. 28
Latuda: Prescribing Information Psychotherapeutic Drugs. In: Archived from the Original on June 28, 2011. [Last accessed on 2010 Dec 17].  Back to cited text no. 29
Latuda. Available from: https://Drugs.com. [Last accessed on 2010 Dec 17].  Back to cited text no. 30
Forester BP, Sajatovic M, Tsai J, Pikalov A, Cucchiaro J, Loebel A. Safety and effectiveness of long-term treatment with lurasidone in older adults with bipolar depression: Post-hoc analysis of a 6-month, open-label study. Am J Geriatr Psychiatry 2018;26:150-9.  Back to cited text no. 31
Sajatovic M, Forester BP, Tsai J, Kroger H, Pikalov A, Cucchiaro J, et al. Efficacy of lurasidone in adults aged 55 years and older with bipolar depression: Post hoc analysis of 2 double-blind, placebo-controlled studies. J Clin Psychiatry 2016;77:e1324-31.  Back to cited text no. 32
Rej S. Lurasidone: A new option for older adults with bipolar disorder? Am J Geriatr Psychiatry 2018;26:160-1.  Back to cited text no. 33


  [Table 1]


Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

  In this article
Case Report
Article Tables

 Article Access Statistics
    PDF Downloaded90    
    Comments [Add]    

Recommend this journal