Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Does the brain 'remember' antidepressants?

27.03.2012
Individuals with major depressive disorder (MDD) often undergo multiple courses of antidepressant treatment during their lives. This is because the disorder can recur despite treatment and because finding the right medication for a specific individual can take time.

While the relationship between prior treatment and the brain's response to subsequent treatment is unknown, a new study by UCLA researchers suggests that how the brain responds to antidepressant medication may be influenced by its remembering of past antidepressant exposure.

Interestingly, the researchers used a harmless placebo as the key to tracking the footprints of prior antidepressant use.

Aimee Hunter, the study's lead author and an assistant professor of psychiatry at UCLA's Semel Institute for Neuroscience and Human Behavior, and colleagues showed that a simple placebo pill, made to look like actual medication for depression, can "trick" the brain into responding in the same manner as the actual medication.

The report was published online March 23 in the journal European Neuropsychopharmacology.

The investigators examined changes in brain function in 89 depressed persons during eight weeks of treatment, using either an antidepressant medication or a similar-looking placebo pill. They set out to compare the two treatments — medication versus placebo — but they also added a twist: They separately examined the data for subjects who had never previously taken an antidepressant and those who had.

The researchers focused on the prefrontal cortex, an area of the brain thought to be involved in planning complex cognitive behavior, personality expression, decision-making and moderating social behavior, all things depressed people wrestle with.

Brain changes were assessed using electroencephalograph (EEG) measures developed at UCLA by study co-authors Dr. Ian Cook, UCLA's Miller Family Professor of Psychiatry, and Dr. Andrew Leuchter, a professor of psychiatry and director of the Laboratory of Brain, Behavior and Pharmacology at UCLA's Semel Institute. The EEG measure, recorded from scalp electrodes, is linked to blood flow in the cerebral cortex, which suggests the level of brain activity.

The antidepressant medication given during the study appeared to produce slight decreases in prefrontal brain activity, regardless of whether subjects had received prior antidepressant treatment during their lifetime or not. (A decrease in brain activity is not necessarily a bad thing, the researchers note; with depression, too much activity in the brain can be as bad as too little.)

However, the researchers observed striking differences in the power of placebo, depending on subjects' prior antidepressant use. Subjects who had never been treated with an antidepressant exhibited large increases in prefrontal brain activity during placebo treatment. But those who had used antidepressant medication in the past showed slight decreases in prefrontal activity — brain changes that were indistinguishable from those produced by the actual drug.

"The brain's response to the placebo pill seems to depend on what happened previously — on whether or not the brain has ever 'seen' antidepressant medication before," said Hunter, who is a member of the placebo research team at the Laboratory of Brain, Behavior and Pharmacology. "If it has seen it before, then the brain's signature 'antidepressant-exposure' response shows up."

According to Hunter, the effect looks conspicuously like a classical conditioning phenomenon, wherein prior exposure to the actual drug may have produced the specific prefrontal brain response and subsequent exposure to the cues surrounding drug administration — the relationship with the doctor or nurse, the medical treatment setting, the act of taking a prescribed pill and so forth — came to elicit a similar brain response through 'conditioning' or 'associative learning.'

While medication can have a powerful effect on our physiology, said Hunter, "the behaviors and cues in the environment that are associated with taking medication can come to elicit their own effects. One's personal treatment history is one of the many factors that influence the overall effects of treatment."

Still, she noted, there are other possible explanations, and further research is needed to tease out changes in brain function that are related to antidepressant exposure, compared with brain changes that are related to clinical improvement during treatment.

Funding for the study was provided by the National Institute of Mental Health, Eli Lilly and Company, Wyeth-Ayerst Laboratories, and Aspect Medical Systems; these funders had no further role in the study. Hunter received financial support from Covidien. For disclosures for Dr. Cook and Dr. Leuchter, please see the full paper.

The UCLA Department of Psychiatry and Biobehavioral Sciences is the home within the David Geffen School of Medicine at UCLA for faculty who are experts in the origins and treatment of disorders of complex human behavior. The department is part of the Semel Institute for Neuroscience and Human Behavior at UCLA, a world-leading interdisciplinary research and education institute devoted to the understanding of complex human behavior and the causes and consequences of neuropsychiatric disorders.

For more news, visit the UCLA Newsroom and follow us on Twitter.

Mark Wheeler | EurekAlert!
Further information:
http://www.mednet.ucla.edu

More articles from Health and Medicine:

nachricht Investigators may unlock mystery of how staph cells dodge the body's immune system
22.09.2017 | Cedars-Sinai Medical Center

nachricht Monitoring the heart's mitochondria to predict cardiac arrest?
21.09.2017 | Boston Children's Hospital

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>