A review on shared clinical and molecular mechanisms between bipolar disorder and frontotemporal dementia

Abstract

Mental disorders are highly prevalent and important causes of medical burden worldwide. Cooccurrence of neurological and psychiatric symptoms are observed among mental disorders, representing a challenge for their differential diagnosis. Psychiatrists and neurologists have faced challenges in diagnosing old adults presenting behavioral changes. This is the case for early frontotemporal dementia (FTD) and bipolar disorder. In its initial stages, FTD is characterized by behavioral or language disturbances in the absence of cognitive symptoms. Consequently, patients with the behavioral subtype of FTD (bv-FTD) can be initially misdiagnosed as having a psychiatric disorder, typically major depression disorder (MDD) or bipolar disorder (BD). Bipolar disorder is associated with a higher risk of dementia in older adults and with cognitive impairment, where a subset of patients presents a neuroprogressive pattern during the disease course. No mendelian mutations were identified in BD, whereas three major genetic causes of FTD have been identified. Clinical similarities between BD and bv-FTD raise the question whether common molecular pathways might explain shared clinical symptoms. Here, we reviewed existing data on clinical and molecular similarities between BD and FTD to propose biological pathways that can be further investigated as common or specific markers of BD and FTD.

Neuropsychiatric Aspects in a Patient Diagnosed with Frontotemporal Dementia: Clinical Case of Low Incidence and Prevalence Disease in Colombia

“…Different researches [ 33 , 34 , 35 ] point out that neurobehavioral disorders such as depression and anxiety have a repercussion on the deficit of neurocognitive functioning, finding an association between the low performance in executive functions and depressive symptomatology. Likewise, it has been found that anxiety has a repercussion on the decline of operative memory; both entities (depression and anxiety) also have a negative impact on the worsening of the quality of life and self-perception of health.…”

Bipolar Disorder Among Patients Diagnosed With Frontotemporal Dementia

“…This overlap in symptoms of bipolar disorder and bvFTD suggests possible shared origins and mechanisms between these two disorders and raises the question of whether bipolar disorder precedes or leads to bvFTD (17). Indeed, a number of investigators have reported a link between the two disorders (18,19), yet the exact association is unclear.…”

Dementia associated with disorders of the basal ganglia

“…This is evidenced in individuals with frontotemporal dementia, particularly frontotemporal lobar degeneration, where atrophy in the frontal and temporal lobes of the brain leads to a profound decline in behavior and language ability (Rabinovici & Miller, ). Both frontotemporal dementia and frontotemporal lobar degeneration appear to have a shared pathological profile with certain psychiatric disorders, particularly bipolar disorder and major depressive disorder (Nascimento et al, ). This indicates that there may be a common underlying pathway driving cognitive disturbances in dementia and psychiatric disorders; the basal ganglia are highly likely to be involved as they have been shown to have abnormalities in both.…”