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August 05, 2014
Veterans' alcohol problems linked to stress on the home front
March 24, 2014
Brain Region Singled Out for Social Memory, Possible Therapeutic Target for Select Brain Disorders
December 18, 2013
Heavy marijuana users have abnormal brain structure and poor memory
December 05, 2013
Mental stress + heart disease: Stronger presence in women under 50
November 10, 2013
OHSU Vollum Institute research gives new insight into how antidepressants work in the brain
October 26, 2013
Alcoholism and Drug Abuse Counselors Continuing Education
June 01, 2013
Ketamine Cousin Rapidly Lifts Depression Without Side Effects
Neurons in a subsection of the adult rat hippocampus are stained with a monoclonal antibody (yellow) that enhances learning and memory. A portion of this antibody is where GLYX-13 came from. Source: Dr. Joseph Moskal, Ph.D., Northwestern University
GLYX-13, a molecular cousin to ketamine, induces similar antidepressant results without the street drug side effects, reported a study funded by the National Institute of Mental Health (NIMH) that was published last month in Neuropsychopharmacology.
Background
Major depression affects about 10 percent of the adult population and is the second leading cause of disability in U.S. adults, according to the World Health Organization. Despite the availability of several different classes of antidepressant drugs such as selective serotonin reuptake inhibitors (SSRIs), 30 to 40 percent of adults are unresponsive to these medications. Moreover, SSRIs typically take weeks to work, which increases the risk for suicide.
Enter NMDA (N-methyl-D-aspartate) receptor modulators. In the 1970s, researchers linked the receptors to learning and memory. Biotech and pharmaceutical companies in the 1980s attempted to apply chemical blockers to these receptors as a means to prevent stroke. But blocking these receptors led to the opposite effect—--the rise of cardiovascular disease. Research in the field dampened until a glutamate receptor antagonist already approved for anesthesia, and known on the streets as “Special K”, ketamine, made headlines in the early 2000s. Human clinical studies demonstrated that ketamine can ward off major and bipolar depressive symptoms within 2 hours of administration and last for several days. Ketamine is fraught with serious side effects including excessive sleepiness, hallucinations, and substance abuse behavior.
“Ketamine lit the field back up,“ said Joseph Moskal, Ph.D., a molecular neurobiologist at Northwestern University and senior study author. “Our drug, GLYX-13, is very different. It does not block the receptor ion channel, which may account for why it doesn’t have the same side effects.”
Moskal’s journey with GLYX-13 came about from his earlier days as a Senior Staff Fellow in NIMH’s Intramural Research Program. While at NIMH, he created specific molecules, monoclonal antibodies, to use as new probes to understand pathways of learning and memory. Some of the antibodies he created were for NMDA receptors. When he moved to Northwestern University, Moskal converted the antibodies to small protein molecules. Comprised of only four amino acids, GLYX-13 is one of these molecules.
Previous electrophysiological and conditioning studies had suggested that GLYX-13, unlike ketamine, enhanced memory and learning in rats, particularly in the brain’s memory hub or hippocampus. GLYX-13 also produced analgesic effects. Using several rat behavioral and molecular experiments, Moskal’s research team tested four compounds: GLYX-13, an inactive, “scrambled” version of GLYX-13 that had its amino acids rearranged, ketamine, and the SSRI fluoxetine.
Results of the Study
GLYX-13 and ketamine produced rapid acting (1 hour) and long-lasting (24 hour) antidepressant-like effects in the rats. Fluoxetine, an SSRI that typically takes from 2–4 weeks to show efficacy in humans, did not produce a rapid antidepressant effect in this study. As expected, the scrambled GLYX-13 showed no antidepressant-like effects at all. The researchers observed none of the aforementioned side effects of ketamine in the GLYX-13–treated rats.
Protein studies indicated an increase in the hippocampus of the NMDA receptor NR2B and a receptor for the chemical messenger glutamate called AMPA. Electrophysiology studies in this brain region showed that GLYX-13 and ketamine promoted long-lasting signal transmission in neurons, known as long-term potentiation/synaptic plasticity. This phenomenon is essential in learning and memory. The researchers propose how GLYX-13 works: GLYX-13 triggers NR2B receptor activation that leads to intracellular calcium influx and the expression of AMPA, which then is responsible for increased communication between neurons.
These results are consistent with data from a recent Phase 2 clinical trial, in which a single administration of GLYX-13 produced statistically significant reductions in depression scores in patients who had failed treatment with current antidepressants. The reductions were evident within 24 hours and persisted for an average of 7 days. After a single dose of GLYX-13, the drug’s antidepressant efficacy nearly doubled that seen with most conventional antidepressants after 4–6 weeks of dosing. GLYX-13 was well tolerated and it did not produce any of the schizophrenia-like effects associated with other NMDA receptor modulating agents.
Significance
NMDA receptors need a molecule each of the amino acid chemical messengers glutamate and glycine to become activated. Moskal speculates that GLYX-13 either directly binds to the glycine site on the NMDA receptor or indirectly modulates how glycine works with the receptor. Resulting activation of more NMDA and AMPA receptors leads to an increase in memory, learning—and antidepressant effects. By contrast, ketamine only blocks the NMDA receptor, but also increases the activity of the AMPA receptor. Knowledge of these mechanisms could lead to the development of more effective antidepressants.
What’s Next
GLYX-13 is now being tested in a Phase 2 repeated dose antidepressant trial, where Moskal and his colleagues at Naurex, Inc., a biotechnology company he founded, hope to find in humans the optimal dosing for the drug. They also want to see if this molecule, and others like it, regulate other NMDA receptor subtypes—there are over 20 of them—and whether it will work on other disorders, such as schizophrenia, attention-deficit hyperactivity disorder, and autism.
“One could call NMDA modulators such as GLYX-13 ‘comeback kids,’” said Moskal. “A toolkit that I developed in 1983 is now setting the stage in 2013 for the development of possible new therapeutics that may provide individuals suffering from depression with a valuable new treatment option.” Alcoholism and Drug Abuse Counselors Continuing Education Reference
Burgdorf J, Zhang X-l, Nicholson KL, Balster RL, Leander JD, Stanton PK, Gross AL, Kroes RA, Moskal JR. GLYX-13, a NMDA Receptor Glycine-Site Functional Partial Agonist, Induces Antidepressant-Like Effects Without Ketamine-Like Side Effects. Neuropsychopharmacology, April 2013. 38:729–742.
February 11, 2013
Imaging Biomarker Predicts Response to Rapid Antidepressant
October 21, 2012
Many Teens Considering Suicide Do Not Receive Specialized Mental Health Care
HomeScience NewsScience News from 2012Science Update • October 12, 2012
Many Teens Considering Suicide Do Not Receive Specialized Mental Health Care
Source: iStockPhotoMost adolescents who are considering suicide or who have attempted suicide do not receive specialized mental health services, according to an analysis published online August 15, 2012, in Psychiatric Services, a journal of the American Psychiatric Association.
Background
National survey data from the Centers for Disease Control and Prevention (CDC) notes that approximately 14 percent of high school students seriously consider suicide each year, 11 percent have a suicide plan, and 6 percent attempt suicide. Other research has suggested that less than half of teens who attempt suicide received mental health services in the year prior to their attempt.Kathleen Merikangas, Ph.D., of NIMH and colleagues analyzed data from the National Comorbidity Survey-Adolescent Supplement (NCS-A), a nationally representative, face-to-face survey of more than 10,000 teens ages 13 to 18. They asked teens whether they had any suicidal thoughts, plans, or actions (ideation) over a one-year period prior to the survey. They also completed a structured diagnostic interview regarding the full range of mental disorders including mood, anxiety, eating and anxiety disorders and whether they had received treatment for emotional or behavioral problems in the past 12 months. Respondents were asked to differentiate between receiving care from a mental health specialist such as a social worker, psychiatrist or other mental health professional, and receiving care from a general service provider, such as a primary care physician.
Results of the study
The survey revealed that, within the past year, 3.6 percent of adolescents had suicidal thoughts, but did not make a specific plan or suicide attempt. In addition, 0.6 percent reported having a plan, and 1.9 percent reported having made a suicide attempt within the past year.Suicidal behavior among youth was not only associated with major depression, but also with a range of other mental health problems including eating, anxiety, substance use and behavior disorders, as well as physical health problems. Between 50 and 75 percent of those teens who reported having suicidal ideation had recent contact with a service provider. However, most only had three or fewer visits, suggesting that treatment tends to be terminated prematurely. Moreover, most teens with suicidal ideation did not receive specialized mental health care.
Significance
The results of this study suggest that depression and other mood disorders are not the only pathways to suicide. They also highlight the importance of integrating risk assessment for suicide into routine physical and mental health care for teens. Even if adolescents are in treatment, they should continue to be monitored for suicidal ideation and behaviors, the researchers concluded.
Reference
Husky M, Olfson M, He J, Nock M, Swanson S, Merikangas K. Twelve-month suicidal symptoms and use of services among adolescents: results from the National Comorbidity Survey. Psychiatric Services in Advance, Aug 15, 2012.
Contact(s)
Colleen LabbeNIMH Press Office301-443-4536NIMHPress@nih.gov
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March 03, 2012
Antidepressant-suicide link in youths absent in new analysis
Drugs also found effective in reducing suicidal behavior in adults, elderly
In 2004, concerns about antidepressant drugs increasing suicidal thoughts and behaviors in young patients prompted the FDA to issue a rare "black box warning." Now, a new analysis of clinical trial data finds that treatment with the antidepressant fluoxetine did not increase — or decrease — suicidality in children compared to placebo treatment.
An analysis built on data from 41 trials and more than 9,000 patients also found that two different popular antidepressant drugs were effective at reducing suicidal behavior and depressive symptoms in adult and geriatric patients. The findings are published online Feb. 6 in the journal Archives of General Psychiatry Alcoholism and Drug Abuse Counselors Continuing Education
The failure to replicate the link between antidepressants and suicide should reassure doctors about prescribing these drugs to depressed patients, said first author Robert Gibbons, PhD, professor of medicine, health studies, and psychiatry at the University of Chicago Medicine.
"The key finding here, when we re-analyze all the patient-level longitudinal records in these studies, is that antidepressants neither increase nor decrease suicidal thoughts or behavior in children," Gibbons said.
The FDA decision on the black box warning was based on retrospective data from 25 clinical trials of newer antidepressant medications, including the serotonin reuptake inhibitor drug fluoxetine, marketed as Prozac or Sarafem. A meta-analysis combining adverse event data (primarily based on self reports of suicidal thoughts) from the trials revealed a small, but significant, increase in suicidal thoughts and behavior in children and young adults up to the age of 25.
For the new analysis, Gibbons and colleagues from the University of Illinois at Chicago, the University of Miami and Columbia University obtained individual-level, longitudinal clinical trial data — some of it unpublished — from pharmaceutical producers and a large National Institute of Mental Health collaborative study of fluoxetine and venlafaxine. The data included weekly screening of each trial subject for depression and suicidal thoughts, allowing researchers to compare the effect of drug or placebo over time on these measures.
In the analysis of the adult and geriatric trials testing fluoxetine or venlafaxine, both antidepressants were found effective in reducing suicide risk and depression symptoms. These two effects were also found to be statistically associated, suggesting that the drugs reduced suicidality by alleviating depression. Therefore, Gibbons said, effective treatment of major depressive disorder is important for a patient's safety.
"Basically, the results say that the mechanism by which the antidepressants affect suicide rates is by decreasing depression," Gibbons said. "It follows that if a treatment is not working for an individual, the risk for suicidal behavior and perhaps worse remains high."
To analyze the effects of antidepressants in children, the researchers used four trials of fluoxetine, which until recently was the only antidepressant approved for pediatric use. Once again, a reduction in depressive symptoms was observed in the drug-treated population compared to placebo. However, no significant change in suicide risk was detected between the two patient groups.
"I think that this paper supports the general idea that the effects of antidepressants in kids and adults are not really the same, since we don't see anything but beneficial effects of antidepressants in adults and geriatrics," Gibbons said. "In kids, we don't see a harmful effect, but we do see a disassociation between the beneficial effects on depression and the potential beneficial effect on suicide."
"This raises continued questions about what's going on in children," he continued. "Maybe children think about suicide in part because of depression, but also maybe due to other reasons not related to depression that are not affected by antidepressants."
Gibbons, who sat on the Food and Drug Administration panel that considered placing the black box warning on antidepressants, said he hoped the new results would reassure clinicians about the safety of the drugs. Previous research by his group found that the addition of the warning significantly reduced antidepressant prescriptions to both children and adults and correlated with a spike in suicide rates.
"I hope that the warnings will not prevent depressed children and adults from getting treatment for depression," Gibbons said. "The greatest cause of suicide is untreated or undiagnosed depression. It's very important that this condition be recognized and appropriately treated and not discarded because doctors are afraid to be sued."
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The paper, "Suicidal Thoughts and Behavior with Antidepressant Treatment," will be published online February 6th by Archives of General Psychiatry. In addition to Gibbons, authors include C. Hendricks Brown of the University of Miami, Kwan Hur of the University of Chicago, John M. Davis of the University of Illinois at Chicago, and J. John Mann of Columbia University. Funding for the research was provided by the National Institute of Mental Health and the Agency for Healthcare Research and Quality.
For more news from the University of Chicago Medical Center, follow us on Twitter at @UChicagoMed, or visit our Facebook page at facebook.com/UChicagoMed, our research blog at sciencelife.uchospitals.edu, or our newsroom at uchospitals.edu/news.
February 21, 2011
Preference for Moving Shapes vs. People Linked to Autism in Babies
A 1-minute video showing computer screensavers next to videos of dancing children may prove to be a simple, inexpensive screening tool for autism spectrum disorders (ASD) in toddlers. According to an NIMH-funded study, infants as young as 14 months old who had autism spent more time looking at the moving shapes than social images, in contrast to typically developing children and those who had delays but not autism. The study was published online, September 6, 2010, in the Archives of General Psychiatry. Alcoholism and Drug Abuse Counselors Continuing Education
Background
Among the hallmark signs of ASD are repetitive behaviors, which may include persistent and intense preoccupation with objects. For example, a child with ASD may fixate on moving objects or parts of objects, like the moving blade of a fan or spinning tires on a car. Whether this behavior could predict or identify ASD in very young children had not previously been studied.
About the study
To study this phenomenon, Karen Pierce, Ph.D., at the University of California San Diego School of Medicine, and colleagues enrolled 110 toddlers, ages 14-42 months. Of this group, 37 had ASD, 22 were developmentally delayed (DD) but did not have ASD, and 51 had typical development (TD).
The toddlers viewed a 1-minute video showing geometric patterns on one side—basically a computer screensaver—and children exercising, dancing, or otherwise in action on the other side. Using eye tracking technology, the researchers measured how long the toddlers looked at each type of movement and how many times they switched from looking at one type or part of an image to another.
Results
In this study, 40 percent of toddlers with ASD spent significantly more time fixating on moving geometric patterns compared with 9.9 percent in the DD group and 1.9 percent of TD children. The other 60 percent of toddlers with ASD performed similarly to their DD and TD peers, showing a preference for social movement. If a toddler spent more than 69 percent of the time fixating on geometric patterns, ASD could be predicted 100 percent of the time.
While viewing the video, DD and TD children tended to let their eyes wander, changing their focus from one part of an image to another. Among toddlers with ASD, however, those who preferred geometric patterns showed significantly less eye movement when viewing geometric patterns, gazing at only a few parts of an image for extended periods of time. These children also showed significantly more frequent eye movement than DD or TD toddlers when viewing social movement.
A subsample of 41 toddlers were re-tested an average of 8 months later. The researchers found that the toddlers' preferences generally stayed the same between the original study and the follow-up.
Significance
The results suggest that assessing infants' visual preference for geometric vs. social movement, including the amount of time they spend staring at moving geometric patterns, is an inexpensive and easy-to-conduct screening method for ASD.
"What an infant prefers to look at when given a choice between two images may turn out to be a more clearly observable indicator of autism risk than how he or she looks at a single image," Pierce said.
That most of the toddlers with ASD in this study responded in the same way as DD and TD children came as a surprise to the researchers. They suggest that differing patterns of brain activity may underlie toddlers' preference for geometric or social movement. Brain imaging studies would help to confirm whether subgroups of ASD can be distinguished by brain activity patterns.
What's Next
According to the researchers, this screening tool may also be useful in identifying babies who would benefit from further developmental evaluation or even early treatment. The findings also provide new lines of inquiry regarding the role of various brain regions involved in processing social cues and shifting attention in the development of ASD.
Sample "social" image (left) and "geometric" image (right) from Pierce's eye tracking study. Forty percent of babies later diagnosed as having autism preferred to look at the moving geometric images, in contrast to just 2 percent of typically developing babies.
Source: Karen Pierce, Ph.D., UC San Diego
Reference
Pierce K, Conant D, Hazin R, Stoner R, Desmond J. A Preference for Geometric Patterns Early in Life is a Risk Factor for Autism. Arch Gen Psychiatry. 2010 Sep 6. [Epub ahead of print]















