Frontotemporal Dementia Presenting With Psychotic Symptoms

Mr. A, a 43-year-old white man, was brought to the emergency department by the police after he pulled out an unloaded gun and “fired” it at a neighbor after a brief altercation. When admitted to the psychiatric unit, the patient chuckled that it was a “joke” and tried to underplay the incident. He was not forthcoming during his initial psychiatric evaluation and more information was obtained from his wife. According to her, Mr. A was fired from his job a couple of years ago following an altercation with a colleague. He was noted to get irritable easily and had also become reclusive. He would spend hours sitting in the dark and listening to rock music and would do nothing around the house. Mr. A was also expelled from his golf club after he made sexual overtures toward a woman. He explained this behavior was a “practical joke” and endorsed that people sometimes would not appreciate his sense of humor. Over the last 2 years, he also developed some psychotic symptoms. He felt that people were staring at him and he would in turn stare back at them. While watching TV, he felt that the characters were “looking” at him. He also believed that his family was plotting against him. On the inpatient unit, he was observed to be hyperphagic with a predilection for ice cream.

On mental status examination, Mr. A was disheveled, appeared disinterested in the interview, and had an air of indifference about him. He would chuckle and sometimes would laugh out loud for no apparent reason. Although he endorsed a depressed mood, he was unable to elaborate any more symptoms of depression. His speech was interspersed with the stock phrase “no problem,” but mostly he displayed a poverty of content of speech. He elaborated referential and persecutory delusions as mentioned above and had grandiose ideas of becoming a rock star. He denied any hallucinations and had no insight into his illness. The patient had no family history of psychiatric or neurologic illness. There was no history of drug and alcohol use. His blood work, including electrolytes, liver/renal function tests, thyroid-stimulating hormone (TSH), rapid plasma reagin, B ₁₂, folic acid, and blood counts were noncontributory. His head CT, done as a part of first-episode psychosis work up, showed prominent bifrontal atrophy and minimal bilateral anterior temporal lobe atrophy. His EEG was normal. Mr. A scored 29/30 on Montreal Cognitive Assessment (he lost a point on abstraction). 3 On the Frontal Assessment Battery, he scored 15/17, losing a point again on abstraction and lexical fluency. 4 Neurologic examination was unremarkable. Based on the typical clinical presentation meeting the consensus criteria for frontotemporal dementia, 5 neuroimaging finding and cognitive testing, Mr. A was diagnosed with frontotemporal dementia. Although a single photon emission computerized tomography (SPECT) study was planned, the patient refused further testing. He was treated with quetiapine, 400 mg b.i.d, and divalproex sodium extended release, 1000 mg b.i.d, (valproate level 79 mg/liter). His psychotic symptoms remitted completely on this combination, but he continued to display the facetious affect, indifference, and lack of insight.

The patient in the index case met the core diagnostic features of the consensus guidelines for frontotemporal dementia. 5 These include insidious onset and gradual progression, early decline in social interpersonal conduct, early impairment in regulation of personal conduct, early emotional blunting, and early loss of insight. Some of these qualifiers also apply to schizophrenia, and if psychotic features along with negative symptoms dominate the presenting picture, frontotemporal dementia is likely to be misdiagnosed as schizophrenia. Indeed, the literature is dotted with reports of frontotemporal dementia being misdiagnosed as schizophrenia or schizophrenia-like psychosis in the early years of its presentation. 2, 6 – 8 In most of these cases, frontotemporal dementia was not diagnosed until several years after the initial diagnosis of a psychotic disorder. In addition to schizophrenia, the social disinhibition and facile euphoria of frontotemporal dementia can also be misconstrued for bipolar disorder. 6 Thus, a clinician needs to have a high index of suspicion for diagnosing frontotemporal dementia. Frontotemporal dementia usually presents in the age range of 35–75 years old, and its earlier age of onset, compared to other types of dementia such as Alzheimer’s dementia, may preclude a clinician from exploring the possibility of frontotemporal dementia in relatively younger patients. 9 Moreover, sociopathic behavior (as in the index case) among patients with frontotemporal dementia is well-documented, 10 and when occurring in the setting of other symptoms of frontal lobe damage, should prompt further investigation into this disorder. Neuroimaging, especially functional neuroimaging, increases the sensitivity of diagnosing frontotemporal dementia, 1 but this may not be available everywhere. Hence, there is a need to develop more neurocognitive tools which can capture this diagnosis.