Based on the distinct patterns of signs and symptoms, three different clinical syndromes have been grouped together under the category of "frontotemporal dementia" (FTD):

1. Behavioral-variant frontotemporal dementia (bvFTD)
2. Semantic dementia (SD) and
3. Progressive non-fluent aphasia (PNFA).

Previously, researchers sometimes used “FTD” to refer only to bvFTD, which has also been called "frontal variant FTD" (fvFTD) or Pick’s Disease. The language variants (SD and PNFA) are sometimes grouped together under the term "primary progressive aphasia" (PPA). PPA has since been split into three subgroups: progressive non-fluent aphasia, semantic dementia and logopenic progressive aphasia (LPA). At autopsy, patients with LPA are often found to have Alzheimer’s disease, not FTLD. SD was previously referred to at times as "temporal variant FTD" (tvFTD).

A small number of people affected by FTD also develop motor neuron disease (FTD/MND), (sometimes called FTD with amyotrophic lateral sclerosis or FTD/ALS).

Corticobasal degeneration (CBD), also called corticobasal syndrome or corticobasal ganglionic degeneration, and progressive supranuclear palsy (PSP) are two related diseases that are not classified as FTD but often share some symptoms with FTD.

In trying to determine what is happening to a person, a doctor must first review the important signs and symptoms with the patient and caregivers. Determination of the neuropsychological, neurological, psychiatric, general medical and functional status of the patient is also important. People with FTD are often misdiagnosed with Alzheimer's disease, psychiatric problems, vascular dementia or Parkinson's disease. MRI can help rule out other diseases and support a diagnosis of FTD.

People with FTD typically first come to the doctor's office because of:

1. Gradual and steady changes in behavior,
2. Gradual and steady language dysfunction or
3. Gradual and steady weakness or slowing of movement

While each type of FTD produces different symptoms, all the types cause a steady decline in the ability to think and function, eventually leaving the person completely dependent on caregivers to get through the day. The disease usually first appears when someone is in their mid-40s to early-60s and lasts an average of eight years.

Unfortunately, there is no way to reverse the damage caused by FTD yet, but many medications and lifestyle changes can help relieve the symptoms. Furthermore, researchers are actively searching for new treatments and running clinical trials to test promising new medications.