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Ritalin: Brain-Damage Evidence For Amphetamines

Ian at Goddard.net Ian at Goddard.net
Wed Dec 29 23:58:35 EST 1999


 
 Below is a press release from Yale University about a 
 study that found short-term low-dose amphetamine use in 
 primates caused possibly permanent cognitive impairment. 
 Researcher Stacy Castner concluded: "It may be the case 
 that even a brief period of low-dose amphetamine abuse 
 in early adolescence or early adulthood can produce 
 profound cognitive deficits that may persist for a 
 couple of years or more after amphetamine use has ended." 

 Ritalin is generally identical to amphetamines, which are 
 also prescribed to suppress the same childhood misbehaviors
 defined as "Attention Deficit Hyperactivity Disorder" (ADHD). 

 We've already seen that therapeutic doses of Ritlin can 
 induce an information-processing dysfunction in human 
 subjects that is also a classic symptom of schizophrenic 
 psychopathology (http://www.erols.com/igoddard/polyrisk.htm 
 also see: http://users.erols.com/igoddard/conyers.htm). 
 Attesting to the brain-impairing power of Ritalin, it's 
 also been shown that Ritalin "induces a psychopathology 
 that seems to mimic schizophrenic psychosis more closely 
 than that induced by amphetamines and cocaine" (Journal
 of Pharmacology and Experiment Therapeutics, 1993 267(1)). 

 A study reported in Science News (December 18 & 25, 1999) 
 found that most of the children receiving behavior therapy 
 had a reduction of ADHD symptoms sufficient to negate any 
 need for drugs. Science News states: "About two-thirds of 
 the children receiving behavioral treatment alone did well 
 enough to stay off medication throughout the study" (see:
 http://sciencenews.org/sn_arc99/12_18_99/fob1.htm). 

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http://www.yale.edu/opa/newsr/99-10-26-02.all.html 
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YALE News Release

EMBARGOED UNTIL 9:15 a.m. Eastern Time, October 27, 1999 

CONTACT: Karen N. Peart, (203) 432-1326 #92 

Yale Study of Long-Term Learning Deficits Resulting From 
Repeated Amphetamine Exposure Could Help Drug Abusers 

New Haven, Conn. -- Repeated exposure to low-dose amphetamines 
can cause deficits in cognitive performance that last for 
several years after the exposure ends, offering insight into 
potential harmful effects of chronic substance abuse in humans, 
a Yale study has found. 

"While previous studies show that acute amphetamine injections 
can impair cognition, our report is the first to demonstrate 
long lasting-over two years-and possibly permanent cognitive 
deficits induced by a brief period of intermittent low-dose 
amphetamine exposure," said Stacy Castner, a researcher on 
the study. "This research could also lead to potential 
treatment of deficits in former drug abusers as well as 
potential drug deterrents in adolescents and young adults." 

To mimic the "binge/crash" pattern of drug abuse in humans, 
Castner gave primates twice-daily injections of chronic 
amphetamine (AMPH), five days per week for six weeks. The 
AMPH dose ranged from 0.1 mg/kg to 1.0 mg/kg and was 
increased by 0.1 mg/kg every three drug days. 

The investigation assessed changes in behavior and videotaped 
the primates to record behavioral responses to each dose of 
AMPH. At six months into the amphetamine exposure, the primates 
were tested on an array of cognitive tasks ranging from 
recognition memory, visual discrimination and spatial working 
memory. Primates previously exposed to amphetamines failed to 
successfully perform the tasks even with continued testing, 
for up to one and a half years. 

"The results show the presence of profound cognitive deficits 
in the amphetamine-treated animals," said Castner, associate 
research scientist in Neurobiology. "This finding could also 
lead to further understanding of other diseases involving 
dysregulation of the brain's dopamine neurons." (more) 

The study, which will be highlighted at the Society for 
Neuroscience annual meeting in Miami, Florida from October 
23-28, is consistent with data from human research where 
commonly abused drugs such as cocaine and ecstasy have been 
found to produce long-lasting and possibly permanent 
cognitive deficits. 

"It may be the case that even a brief period of low-dose 
amphetamine abuse in early adolescence or early adulthood 
can produce profound cognitive deficits that may persist 
for a couple of years or more after amphetamine use has 
ended," said Castner. 

The investigators' ongoing research includes experiments 
involving neurotransmitters that will help explain the long-
lasting cognitive deficits in primates. They are also 
conducting experiments to reverse the AMPH-induced cognitive 
deficits in the same group of primates and they plan to 
investigate the biochemical and structural changes in the 
primate brain that could account for the behavioral deficits. 

This study was supported by the Center for Neuroscience in 
Mental Disorders from the National Institutes of Health. 
Patricia S. Goldman-Rakic, professor of neurobiology at 
Yale was principal investigator. 

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http://www.yale.edu/opa/newsr/99-10-26-02.all.html 
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GODDARD'S JOURNAL: http://www.erols.com/igoddard/journal.htm 
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