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
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:
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
"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.
GODDARD'S JOURNAL: http://www.erols.com/igoddard/journal.htm