Frontotemporal dementia !

A dementia that starts earlier than Alzheimer disease and first changes behaviour, personality or language, with memory spared at the beginning.

Updated 2026-11-01

Structures involved

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Why it happens

What it is

A group of neurodegenerative disorders with progressive atrophy of the frontal and/or anterior temporal lobes (frontotemporal lobar degeneration). It presents with changes in behaviour and personality or with progressive loss of language, usually before age 65.

Who gets it

It is one of the most common causes of dementia in people younger than 65, with onset usually between 45 and 64 and equal frequency in men and women. In Latin America it is often first seen in psychiatry because the early picture looks like depression, mania or a personality disorder, which delays diagnosis.

Causes

Abnormal accumulation of tau protein (including Pick bodies) or TDP-43 in frontal and temporal neurons
Familial forms in a substantial minority, mainly variants in MAPT, GRN or C9orf72
C9orf72 expansions link it with amyotrophic lateral sclerosis in the same patient or family

Risk factors

Family history of dementia, early psychiatric illness or motor neuron disease
Age between 45 and 65

Pathophysiology

Abnormal tau or TDP-43 aggregates cause neuronal loss and gliosis in the frontal lobes, anterior temporal lobes, insula and anterior cingulate gyrus, regions that control social behaviour, empathy, judgement and language. Atrophy is often asymmetric: left-sided disease affects language, right-sided disease affects behaviour and recognition of people. The hippocampus and memory circuits are relatively spared early, unlike in Alzheimer disease.

Classification

Behavioural variant (most common): disinhibition, apathy, loss of empathy, compulsive behaviours and hyperorality
Semantic variant primary progressive aphasia: fluent speech but loss of word meaning and object knowledge (anterior temporal lobe)
Non-fluent/agrammatic variant primary progressive aphasia: effortful, halting speech with grammar errors (left inferior frontal lobe and insula)
Overlap syndromes: with motor neuron disease, progressive supranuclear palsy or corticobasal syndrome

Symptoms and signs

Socially inappropriate behaviour, impulsivity and loss of manners
Apathy and loss of interest, often mistaken for depression
Loss of empathy and concern for others
Repetitive or compulsive behaviours and rigid routines
Overeating, sweet cravings or putting objects in the mouth
Poor judgement and planning, with little insight
Progressive difficulty finding or understanding words
Memory and orientation relatively preserved early

Diagnosis

Clinical: Clinical diagnosis based on progressive behavioural or language decline, with collateral history from family. Neuropsychological testing shows executive dysfunction or language deficits with relatively preserved memory and visuospatial skills.
Tests: Blood tests exclude reversible causes (vitamin B12, thyroid function, syphilis and HIV serology). Cerebrospinal fluid biomarkers may help exclude Alzheimer disease. Genetic testing is considered when there is a family history.
Imaging: MRI shows frontal and/or anterior temporal atrophy, often asymmetric ("knife-edge" atrophy). FDG-PET or SPECT shows frontal and temporal hypometabolism or hypoperfusion when MRI is not conclusive.

Differential diagnosis

Alzheimer disease (including its frontal variant)
Major depressive disorder, bipolar disorder or late-onset psychosis
Dementia with Lewy bodies and vascular dementia
Prion disease (Creutzfeldt-Jakob disease)
Frontal lobe tumours or normal-pressure hydrocephalus
Neurosyphilis and HIV-associated neurocognitive disorder

Goal of treatment

There is no disease-modifying treatment; care aims to control behaviour, keep the person and others safe, support language and communication, and support and train caregivers.

Treatment

Medical: Selective serotonin reuptake inhibitors (or trazodone) for disinhibition, compulsions and food cravings; antipsychotics only for severe agitation, with caution. Cholinesterase inhibitors are not effective and can worsen behaviour.
Conservative: Structured routines, supervision, removal of access to money, car keys or dangerous objects, and behavioural strategies for caregivers.
Rehabilitation: Speech and language therapy to maintain communication in the language variants; occupational therapy.
Follow-up: Regular review of behaviour, weight, swallowing, motor signs (motor neuron disease) and caregiver burden; early advance care planning while the person can still take part.

Complications

Loss of independence and need for full-time care
Financial, legal and social problems from impulsive behaviour
Aspiration pneumonia and weight changes
Caregiver burnout

Prognosis

Progressive; survival is usually about 6 to 11 years from symptom onset, and shorter when associated with motor neuron disease.

Test yourself

Think of the answer, then tap the question to see it.

Which brain regions are atrophied in frontotemporal dementia?

The frontal and anterior temporal lobes, often asymmetrically, with relative sparing of the hippocampus early.

What inclusions are characteristic of Pick disease?

Pick bodies: round intracellular aggregates of tau protein.

How does early frontotemporal dementia differ from Alzheimer disease clinically?

It starts earlier and presents with behaviour, personality or language changes while memory is relatively preserved.

Which motor disease is linked with frontotemporal dementia through C9orf72 expansions?

Amyotrophic lateral sclerosis.

Which drug class is used for disinhibition and compulsive behaviours in frontotemporal dementia?

Selective serotonin reuptake inhibitors; cholinesterase inhibitors are not helpful.

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Educational information, not medical advice. For any symptom, see a health professional.

Sources: Frontotemporal dementia: MedlinePlus Medical Encyclopedia (MedlinePlus (U.S. National Library of Medicine), 2026).

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Representative model, for educational purposes only.

Frontal lobe highlighted on the Durgical 3D model