Frontotemporal dementia (formerly referred to as Pick's disease
and sometimes referred to as frontotemporal lobar degeneration)
is characterized in its early stages by changes in personality,
significant apathy, executive dysfunction, deterioration of social
skills, emotional blunting, behavioral disinhibition, and prominent
language abnormalities. Difficulties with memory, apraxia, and other
features of dementia usually follow later in the course. As the
dementia progresses, it may be accompanied by extreme agitation.
Individuals may develop such severe problems with language, attention,
or behavior that it may be difficult to assess the degree of cognitive
impairment. Early prominent changes in personality and behavior,
severe apathy, and/or early language deficits help to distinguish
this group of disorders from Alzheimer's disease. Two sets
of diagnostic criteria for frontotemporal dementia spectrum disorders
have been proposed (361, 425). The criteria
of McKhann et al. include several disorders previously considered
to be distinct: progressive supranuclear palsy, corticobasal ganglionic
degeneration, amyotrophic lateral sclerosis with dementia, and hippocampal sclerosis
(361, 426). Argyrophilic grain disease
may also be included in this group of conditions (427).
In frontotemporal dementia spectrum disorders, structural brain
imaging typically reveals prominent frontal and/or temporal
atrophy, with relative sparing of the parietal and occipital lobes.
The formal diagnosis of Pick's disease, which is only one
of the numerous neuropathological subtypes of this condition, depends
on the neuropathological finding of Pick inclusion bodies (361).
About one-third of cases are familial, and a number of specific
genetic defects have been identified (29). The disorder
most commonly manifests in patients ages 50–60 years, although
it can occur among older or younger individuals. The course is progressive
and can be more rapid than that of Alzheimer's disease,
although there is significant heterogeneity. Once thought to be
rare, these conditions have been found to be more common, and careful
assessment may reveal cases previously missed. These conditions
are important for psychiatrists because they often present with
a variety of psychiatric symptoms, including disinhibition, apathy, depression,
anxiety, personality change, substance abuse, family conflict, and
impaired work performance, that initially overshadow the cognitive
impairment, complicating and delaying the proper diagnosis.