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Table of Contents    
Year : 2021  |  Volume : 69  |  Issue : 5  |  Page : 1356-1358

Idiopathic Normal Pressure Hydrocephalus Presenting as Psychosis

1 Prof and Head of Neurology, Sree Mookambika Institute of Medical Sciences, Padanilam, Kulasekharam, Tamil Nadu, India
2 Associate Professor, Psychiatrist, Anugraham Neurocare, Murinjapalam, Trivandrum, Kerala, India
3 Department of Neurology, Pushpagiri Institute of Medical Sciences, Thiruvalla, Kerala, India

Date of Submission26-Nov-2019
Date of Decision27-Nov-2019
Date of Acceptance14-Jul-2020
Date of Web Publication30-Oct-2021

Correspondence Address:
Robert Mathew
KMLRA136, Mosque Lane, Kumarapuram, Medical College P.O, Trivandrum - 695 011, Kerala
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0028-3886.329621

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 » Abstract 

Background: Normal pressure hydrocephalus (NPH) is a syndrome characterized by gait disturbance, dementia, urinary incontinence, and dilation of ventricular system with normal opening cerebrospinal fluid pressure. Idiopathic NPH (i NPH) presenting as psychosis is uncommon.
Objectives: The objective of this study is to describe idiopathic NPH presenting as Psychosis.
Subjects and Methods: Patients availing dementia care service from three tertiary care hospitals, across Kerala, with a diagnosis of psychosis were evaluated.
Results: Three patients with NPH, diagnosed as per the consensus criteria, presenting as psychosis are described. Patient 1: Fifty-five-year-old lady with psychosis was found to have iNPH. She gave history of psychosis relieved with successful shunting of the hydrocephalus. She developed recurrence of psychosis each time the hydrocephalus recurred due to shunt malfunction and was relieved with correction of hydrocephalus with shunting. Patient 2 was a 67-year-old gentleman with long history of pyschosis with paranoid ideas. Five years after onset of illness, he developed gait apraxia, and a CT scan done showed normal pressure hydrocephalus. Patient 3 had bipolar illness since age of 60 years of age. He also developed gait apraxia 5 years into the illness and was diagnosed as having iNPH following imaging.
Conclusions: All the patients had psychosis much before other features of iNPH developed. One of the patient's psychosis was temporally associated with onset and offset of hydrocephalus, thereby strongly supporting the causative nature of iNPH. iNPH though rare can be one of the causes for late onset secondary psychosis.

Keywords: Dementia, normal pressure hydrocephalus, psychosis, shunt
Key Message: Idiopathic NPH presenting as psychosis is uncommon. Improvement of psychosis with CSF shunting procedure supports causal relation between iNPH and psychosis. If diagnosed timely and treated with shunt surgery, psychosis can be cured.

How to cite this article:
Mathew R, Archana N U, Sheetal S. Idiopathic Normal Pressure Hydrocephalus Presenting as Psychosis. Neurol India 2021;69:1356-8

How to cite this URL:
Mathew R, Archana N U, Sheetal S. Idiopathic Normal Pressure Hydrocephalus Presenting as Psychosis. Neurol India [serial online] 2021 [cited 2021 Nov 30];69:1356-8. Available from:

Normal pressure hydrocephalus is a syndrome characterized by gait disturbance, dementia, urinary incontinence, and dilation of ventricular system with normal opening cerebrospinal fluid pressure.[1] A cross-sectional hospital-based study from south India has shown 59.2% of dementia patients had iNPH.[2] iNPH is considered as a common cause of potentially reversible dementia.[3],[4],[5],[6]

Many iNPH patients have psychiatric symptoms associated with the illness, predominantly apathy and depression. Psychotic syndromes and bipolar disorders were also seen.[1] The correlation between neuropsychiatric symptoms and cognitive impairment in NPH appears to arise from a common pathology in the frontal lobe.

The aim of the study was to describe clinical features of patients with iNPH presenting as psychosis.

 » Subjects and Methods Top

This was a cross-sectional prospective descriptive study. Patients attending three different tertiary care centers from 2010 to 2017 for dementia evaluation were included. Patients diagnosed as having probable or possible iNPH as per the consensus criteria were included in the study if their presenting symptoms were predominantly that of psychosis. Informed consent was taken from all patients.

 » Results Top

Three patients satisfying above-mentioned criteria were selected, and their clinical features were described in detail.


A 50-year-old lady was brought with history of psychosis, in the form of delusions and hallucination, for last 10 years, starting at the age of 45. She was diagnosed as having bipolar illness by psychiatrist and initiated on neuroleptics, with partial response. She was found to have hydrocephalus. She underwent ventriculoperitoneal shunt, with a nonprogrammable valve following which her psychotic symptoms improved and neuroleptics could be withdrawn. After 3 years, she had recurrence of psychotic symptoms. CT brain showed features of recurrence of hydrocephalus, indicating shunt malfunctioning. She underwent a repeat ventriculoperitoneal shunt with a nonprogrammable valve and had improvement in the psychotic symptoms. She subsequently developed psychotic features after 5 years and was again found to have shunt malfunction. She underwent revision of shunt on the left and had improvement of symptoms. After 2 years, she had recurrence of psychotic symptoms, and CT scan showed recurrence of hydrocephalus. The patient was not willing for any further surgical intervention, and she was initiated on neuroleptics.

Patient 2

A 67-year-old retired military officer developed paranoid ideas, suspiciousness, and agitation, since 60 years of age. By the age of 65, he developed slowness of gait. A CT scan done showed hydrocephalus, but no further investigations were done. Two years later, he was involved in a road traffic accident, sustained head injury, and was bradykinetic and mute. MRI brain showed hydrocephalus. He underwent CSF study, and the pressure was found to be 110 mm CSF and 30 ml was drained. He showed mild improvement initially; however, a repeat tap done after 3 days did not lead to any further improvement.

Patient 3

A 67-year male was under treatment for psychotic symptoms characterized by delusions and hallucinations for 5 years. Later he developed walking difficulty and was noted to have gait apraxia. MRI scan of brain showed hydrocephalus. The patient was not willing for further evaluation, and hence CSF tap test could not be done.

 » Discussion Top

All our patients qualified for diagnosis of iNPH as per the consensus criteria.[7] One patient had probable and two patients had possible iNPH. All the three patients had psychosis as the most prominent symptom in the initial few years of disease onset before development of gait abnormality. Psychosis even now lacks a unified definition; it denotes a clinical construct composed of many symptoms.[8] American Psychiatric Association and the World Health Organization define psychosis in the presence of (without insight into their pathologic nature) delusions or both hallucinations without insight and delusions.[9] All our patients had psychosis as per this definition. In one patient, temporal relation of the psychotic episodes to the onset and offset of hydrocephalus could be document.

Cases of iNPH presenting as psychosis are sparse. Alegeti S, et al. had reviewed the available case reports until May 2015 and could identify only 11 cases in literature prior to their case. One of these patients had good improvement in psychosis postsurgery and could discontinue neuroleptics.[10] Improvement of psychosis with CSF shunting procedures supports causal relation between iNPH and Psychosis. Data showing improvement of psychosis in iNPH, consequent to CSF shunt procedure, is sparse. Patient 1 is unique in that she had relief of psychosis three times with the CSF shunt procedure and worsening of psychosis three times consequent to worsening of hydrocephalus. The significant improvement of psychosis with the shunt procedure is supported by the fact that she could discontinue neuroleptics after the procedure.

In one of the recent studies on Alzheimer's dementia (AD), 1-year psychosis incidence was 10% and cumulative psychosis incidence at 5 years was 61%.[11] Psychosis in iNPH is a well-described entity. In one of the recent studies in which formal psychiatric evaluation was done in 35 patients, 71% was found to have psychiatric symptoms mostly in the form of anxiety, depression, and psychotic syndromes.[1] However, iNPH presenting as psychosis is uncommon, there being only few case reports.[12],[13]

Neurodegenerative diseases (ND) are often misdiagnosed as psychosis. Our study adds one more condition to the list of NDs presenting as psychosis. BvFTD (Behavioral variant of fronto- temporal dementia) patients received a prior psychiatric diagnosis significantly more often (52.2%) than patients with AD (23.1%), semantic dementia (24.4%), or progressive nonfluent aphasia (11.8%), and were more likely to receive diagnoses of bipolar affective disorder or schizophrenia than patients with other NDs.[14] Statistics on iNPH being misdiagnosed as psychosis is not available. It has been estimated that approximately 60% of older patients with newly incident psychosis have a secondary psychosis.[15] It is a well-accepted fact that patients with a ND often receive psychiatric diagnoses. Our observations point to the fact that this can happen in iNPH as well. However, the percentage of iNPH contributing to secondary cause of psychosis in elderly is not known. Till now, there is no postulation on biologic or structural corelated with psychosis in patients with iNPH. More cases of iNPH presenting as psychosis need to be analyzed for any structural postulations to be made.

 » Conclusion Top

This study throws light to the fact that iNPH though rare can be one of the causes for late onset secondary psychosis.

Declaration of patient consent

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

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

 » References Top

Oliveira MF, Oliveira JR, Rotta JM, Pinto FC. Psychiatric symptoms are present in most of the patients with idiopathic normal hydrocephalus. Arq Neuropsiquiatr 2014;72:435-8.  Back to cited text no. 1
Mathew R, Pavithran S. Cognition in advanced normal pressure hyrdocephalus: A pilot study from South India. Neurol India 2017;65:729-31.  Back to cited text no. 2
[PUBMED]  [Full text]  
Thomsen AM, Borgesen SE, Bruhn P, Gjerris F. Prognosis of dementia in normal-pressure hydrocephalus after a shunt operation. Ann Neurol 1986;20:304-10.  Back to cited text no. 3
Katzen H, Ravdin LD, Assuras S, Heros R, Kaplitt M, Schwartz TH, et al. Postshunt cognitive and functional improvement in idiopathic normal pressure hydrocephalus. Neurosurgery 2011;68:416-9.  Back to cited text no. 4
Duinkerke A, Williams MA, Rigamonti D, Hillis AE. Cognitive recovery in idiopathic normal hydrocephalus after shunt. Cogn Behav Neurol 2004;17:179-84.  Back to cited text no. 5
Gleichgerrcht E, Cervio A, Salvat J, Loffredo AR, Vita L, Roca M, et al. Executive function improvement in normal pressure hyrdrocephalus following shunt surgery. Behav Neurol 2009;21:181-5.  Back to cited text no. 6
Relkin N, Marmarou A, Klinge P, Bergsneider M, Black PM. Diagnosing idiopathic normal-pressure hydrocephalus. Neurosurgery 2005;57:14-6.  Back to cited text no. 7
Gaebel W, Zielasek J. Focus on psychosis. Dialogues Clin Neurosci 2015;17:9-18.  Back to cited text no. 8
Arciniegas DB. Psychosis. Continuum 2015;21:715-36.  Back to cited text no. 9
Aligeti S, Burson RR. New onset psychosis with idiopathic normal pressure hydrocephalus. J Med Allied Sci 2015;5:48-50.  Back to cited text no. 10
Weamer EA, DeMichele-Sweet MA, Cloonan YK, Lopez OL, Sweet RA. Incident psychosis in subjects with mild cognitive impairment or Alzheimer's disease. J Clin Psychiatry 2016;77:1564-9.  Back to cited text no. 11
Kwentus JA, Hart RP. Normal pressure hydrocephalus presenting as mania. J Nerv Ment Dis 1987;175:500-2.  Back to cited text no. 12
Yusim A, Anbarasan D, Bernstein C, Boksay I, Dulchim M, Lindenmayer JP, et al. Normal pressure hydrocephalus presenting as Othello syndrome: Case presentation and review of the literature. Am J Psychiatry 2008;165:1119-25.  Back to cited text no. 13
Wooley JD, Khan BK, Murthy NK, Miller BL, Rankin KP. The diagnostic challenge of psychiatric symptoms in neurodegenerative disease: Rates of and risk factors for prior psychiatric diagnosis in patients with early neurodegenerative disease. J Clin Psychiatry 2011;72:126-33.  Back to cited text no. 14
Reinhardt MM, Cohen CI. Late-life psychosis: Diagnosis and treatment. Curr Psychiatry Rep 2015;17:1.  Back to cited text no. 15


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