Posted by Sunnely on May 26, 2001, at 0:07:11
In reply to Re: Tardive Dyskinesia = Cam, Sunnely, anyone?, posted by SLS on May 25, 2001, at 22:34:43
Hi Scott,
Just responding to your post and not to any of the previous ones.
In a prospective study done by (John) Kane et. al., 1988, involving over 850 patients, assessed for TD every 3 months, the following were their findings:
1) Mean age of the patients - 29 years
2) 43% of patients were females
3) 12 months - median length of exposure to neuroleptics
4) The incidence rate (number of new cases occurring in a population during a specified time period and does not count for all currently affected patients):
a) 5% after 1 year
b) 10% after 2 years
c) 15% after 3 years
d) 19% after 4 years
e) 23% after 5 years
f) 26% after 6 years
The incidence rate increases as the duration of neuroleptic treatment increases, and there is a linear progression for the first several years.
Incidentally, John Kane, MD (from NY) is one of the psychopharmacology gurus. He led the multicenter (US) clozapine clinical trials in 1988 that led to its subsequent FDA approval.
You're right. Believe it or not, the rate of TD developing in bipolar disorder patients is higher than in schizophrenia patients.
Incidentally, the following are the risk factors for TD:
1) Age - is the most consistent risk factor. Five percent of young patients develop TD after 1 year compared to 30% in the elderly. Also, TD is more severe and persistent in older patients. The rates of remission if the neuroleptics is discontinued after TD develops is as follows: over 60 years old = 36% while younger than 60 = 83%. Caution: Not all involuntary mouth movements in the elderly is TD. Five percent of the elderly develop spontaneous oral dyskinesia in the absence of neuroleptic treatment.
2) Sex - women appear to have higher rate of developing TD than men. However, evidence suggests that this is limited to the geriatric age range. It appears that there is an increased risk for older women than younger women. The exact reason is unclear but suggested that hormonal factors may play a role (e.g., estrogen may act as protective mechanism to TD).
3) Organic brain syndromes - it appears that patients with dementia (e.g. Alzheimer's and others), mental retardation, and history of brain injury are at higher risk for TD.
4) Affective or mood disorders (e.g., depressive disorders and bipolar disorders), compared to schizophrenia, may be particularly susceptible to both an earlier onset and severity of TD. However, recovery may be more rapid than in nonmood disodered patients.
5) Type of neuroleptics - virtually all conventional neuroleptics have been reported to cause TD. The risk of TD appears to be much less with the newer (atypical) neuroleptics. Among the atypical neuroleptics, TD seems to be most likely to occur with the use of risperidone (Risperdal).
6) Dosage and duration of neuroleptic use - the higher the dose, the longer the period of treatment, the greater the risk of TD. The "intermittent (or targeted)" neuroleptic form of therapy is more likely to cause TD than the "continuous low-dose" neuroleptic form of treatment.
7) Concomitant use of anticholinergic drugs (e.g., benztropine, trihexyphenidyl, etc.) higher risk for TD.
8) Early signs of extrapyramidal symptoms (EPS) such as acute dystonia, akathisia, parkinsonism, are more likely to develop TD with continued neuroleptic treatment.
9) Smoking - appears to be associated with increase rate of TD. It was sugggested that nicotine stimulates dopamine release from the nigrostriatal neurons. On the other hand, there appears to be an inverse relationship between smoking and the rate of Parkinson's disease.
10) Alcoholism - schizophrenic patients with history of alcohol abuse appear to have a significantly higher TD scores than nonabuser schizophrenics.
11) Diabetics - on neuroleptics have higher rate of developing TD than nondiabetics on neuroleptics.
12) Ethnicity - in one study (4 continents), the lowest rate of TD was reported in Asia.
13) Unknown individual factors - possibly a genetically determined vulnerability to TD plays an essential part.
14) TD can also develop in patients taking nonneuroleptic drugs such as metoclopramide (Reglan), for stomach distress. Reglan is actually a dopamine receptor blocker belonging to the class of substituted benzamides, which also include neuroleptics such as sulpiride, amisulpiride, remoxipride, raclopride, emonapride.
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> > the rates of TD are 5-7% per year in healthy young adults (I believe that is 1 in 20). The rate is cumulative so that 25-35% of patients will develop the disorder in 5 years of treatment (not uncommon in schizophrenia or bipolar disorder). I believe that is 1 in 4 people. Among the elderly the rate of TD is 20% or more/year (Frenkel et al (1992- Pg 11). Most of these statistics are found in standard textbooks. I am glad you and others on this board have been helped by neuroleptics, I am presenting statistics that are widely published and that have permanently affected me.
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> These statistics are really scary. I may have to consider taking a Zyprexa-type drug indefinitely, so for me they are very relevant.
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> What statistics or characterizations of risk do you believe represent the incidences of tardive-dyskinesia with various antipsychotics and dosages?
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> Thanks.
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> I read something that suggested that the rate of TD is actually higher in people being treated for bipolar disorder than for schizophrenia.
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> - Scott
poster:Sunnely
thread:64133
URL: http://www.dr-bob.org/babble/20010522/msgs/64300.html