1) The case report describes a 28-year-old man with schizophrenia who developed palilalia, the involuntary repetition of words or phrases, after being prescribed 300 mg of clozapine.
2) Palilalia disappeared after lowering the clozapine dose to 150 mg, suggesting it was a dose-dependent side effect of the drug.
3) While palilalia has been associated with various neurological disorders, this appears to be a rare case of drug-induced palilalia from clozapine, via possible effects on dopaminergic and serotonergic systems in the basal ganglia.
2. Rare side-effect
(5). Palilalia has also appeared in stimulation exper- But some authors have pointed out that it is often
iments of left hemisphere sites and following stereo- linked to the production of propositional, effort-
taxic thalamotomy as well as a side effect of ful speech such as spontaneous speech, sentence
neuroleptic medication (6). formulation, picture description or naming. This sug-
The pathogenesis of palilalia is still unclear. Basal gests that palilalia can also receive input from a
ganglia and extrapyramidal system involvement has central, prearticulatory generator (cognitive hypoth-
been suggested as the cause of some cases and it esis) (4). Other pathophysiologic mechanisms impli-
has been proposed that palilalia reflects an inhibitory cated could be neuron degeneration and neurotrans-
problem originated from a failure of subcortical mitter disturbances (7).
inhibitory systems. It is hypothesised that there is Language disturbances associated with clozapine
a failure of the speech motor processing system after are rare and generally assume the form of acquired
the formation of the phonetic plan, but before the stuttering (8).
level of the muscle action (4). One possible explanation for palilalia induced
In the next section we describe a case of a patient by clozapine is the disruption of the nigrostriatal
with palilalia induced by clozapine. As we have dopaminergic pathways leading to basal ganglionic
mentioned before, palilalia has been associated with dysfunction.
various disorders, but has seldom been reported as Lesions selectively involving the medial substantia
an antipsychotic side effect. nigra producing anterior putaminal dopaminergic
dysfunction can produce palilalia without motor
symptoms in the extremities (9). Clozapine could
Clinical case produce this effect with D2 antagonism in basal
A 28-year-old Caucasian man, diagnosed as suffering ganglia.
from resistant paranoid schizophrenia, was admitted This is related with the motor hypothesis of
to acute inpatient treatment. The patient had auditory palilalia, which holds that repetitive speech phenom-
hallucinations and persecutory delusions that failed ena are the result of a malfunction at the level of
to respond initially to 160 mg of ziprazidone, and motor speech, probably resulting from a disintegra-
then to 8 mg of risperidone. For that, he was tion of subcortical–cortical interplay, whereby the
started on clozapine, and subsequently he developed basal ganglia stimulate speech activity in the cortex
palilalia when dosage reached 300 mg. His speech in an uncontrolled manner; alternatively, defective
had several repetitions of his own words or phrases execution of pre-programmed motor sequences may
at a constant rate and amplitude. There was no result in an impairment of the duration and fluency
history of illicit drug misuse. Physical examination of speech events (4).
was unremarkable as well as blood investigations. Another possible explanation for palilalia induced
An electroencephalogram (EEG) revealed unspecific by clozapine is related with the lowering of epilep-
overactivity without point wave activity and a tic threshold and the emergence of epileptic activity
cerebral magnetic resonance (CMR) showed no that can culminate in major motor seizures, one of
alterations. The dose of clozapine was reduced to clozapine side effects. This is also the explanation for
150 mg and palilalia ceased. clozapine-induced stuttering (10). Finally, as clozap-
ine shares some properties with other antipsychotics,
we may expect to see palilalia as a side effect of this
Discussion pharmacological group.
Palilalia may be a rare side effect. In this case
report, there was a dose-dependent onset of palilalia Comments
with clozapine, which ceased when the dosage was
The above case report highlights clozapine as being
reduced. As clozapine acts predominantly by block-
possibly implicated in the pathogenesis of palilalia.
ing D2 and 5-HT2 receptors, possibly dopaminergic
To our knowledge no similar cases have been
and serotonergic system may be involved in this phe-
reported. Physicians should consider palilalia as a
nomenon.
pharmacologic side effect in patients treated with
Causes of palilalia are many. The patient under-
clozapine. Further research is required to identify
went investigation including CMR, which showed
the neurophysiological and psychological basis of
no alterations and EEG, which revealed unspecific
palilalia.
alterations.
The usual explanation for palilalia is a disorder of
motor speech which may be a possible counterpart References
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