Several etiologies can underlie the development of late-onset psychosis, defined by first psychotic episode after age 40 years. Late-onset psychosis is distressing to patients and caregivers, often difficult to diagnose and treat effectively, and associated with increased morbidity and mortality.

The literature was reviewed with searches in Pubmed, MEDLINE, and the Cochrane library. Search terms included “psychosis,” “delusions,” hallucinations,” “late onset,” “secondary psychoses,” “schizophrenia,” bipolar disorder,” “psychotic depression,” “delirium,” “dementia,” “Alzheimer’s,” “Lewy body,” “Parkinson’s, “vascular dementia,” and “frontotemporal dementia.” This overview covers the epidemiology, clinical features, neurobiology, and therapeutics of late-onset psychoses.

Late-onset schizophrenia, delusional disorder, and psychotic depression have unique clinical characteristics. The presentation of late-onset psychosis requires investigation for underlying etiologies of “secondary” psychosis, which include neurodegenerative, metabolic, infectious, inflammatory, nutritional, endocrine, and medication toxicity. In delirium, psychosis is common but controlled evidence is lacking to support psychotropic medication use. Delusions and hallucinations are common in Alzheimer’s disease, and hallucinations are common in Parkinson’s disease and Lewy body dementia. Psychosis in dementia is associated with increased agitation and a poor prognosis. Although commonly used, no medications are currently approved for treating psychosis in dementia patients in the USA and nonpharmacological interventions need consideration.

The plethora of possible causes of late-onset psychosis requires accurate diagnosis, estimation of prognosis, and cautious clinical management because older adults have greater susceptibility to the adverse effects of psychotropic medications, particularly antipsychotics. Research is warranted on developing and testing efficacious and safe treatments for late-onset psychotic disorders.

We present the case of a 34-year-old female patient with no prior psychiatric record who was treated in our outpatient department due to persecutory delusions of recent onset. The patient had a history of refractory temporal epilepsy since adolescence and underwent a temporal lobe resection 4 month prior to the appearance of her symptoms.

Temporal lobe resection is a well-established technique to treat refractory temporal lobe epilepsy in which psychotic symptoms are an infrequent complication; the most frequent being cognitive sequelae, visual field defects and depression. According to several sources, this symptomatology may be underdiagnosed and undereportend and there have been a number of case reports and series of cases which describe the aforementioned entity.

A case report is presented alongside a review of the relevant literature regarding cases of secondary psychosis after brain surgery.

During her treatment we administered olanzapine up to doses of 7.5mg per day because of the risk of reducing the convulsive threshold. We observed a marked improvement and the disappearance of the delusions. The dose of olanzapine has been maintained for a year with no important side-effects and without a relapse in symptoms.

Psychotic symptoms as a complication of temporal lobe resection may be more frequent than what was thought in the past. It is important to study this phenomenon more in-depth because the symptoms may remain undetected and present worse outcomes given that there are effective treatments which could ameliorate the condition.

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