With June being Post-traumatic stress disorder (PTSD) awareness month, I wanted to take a closer look at PTSD and what is happening in the brain. What is PTSD? Who does it affect? And what is the correlation between PTSD and addiction? The National Institute of Mental Health estimates that 7.7 million Americans, 18 years and older, suffer from Post-traumatic stress disorder (PTSD). According to Science Daily, the number of self-reported PTSD cases has tripled among combat-exposed military personal since 2001. Read more →
The ability for scientists to block memories seems like the plot of a sci-fi movie. In fact, if you’ve ever seen the movie “Eternal Sunshine of the Spotless Mind” then you’ll know how the characters attempted to erase memories associated with emotional experiences. Well, new research from Western University shows how scientists were able to block memory recall that is prevalent in PTSD and addiction sufferers, often hindering treatment and increasing relapse risk. Read more →
Scientists have identified a molecule, called CGP3466B, that in a recent study blocked cocaine addiction in mice. Scientist had already been testing the molecule or compound CGP3466B on humans for the treatment of Parkinson’s disease and amyotrophic lateral sclerosis, but it was unsuccessful. Once researchers learned which brain pathway cocaine acts on, they knew CGP3466B blocked that specific pathway.
The new study tested mice by giving them a choice of visiting two room, one of which occasionally dispensed cocaine. When the mice spent all of their time in the cocaine room, they were considered addicted. Those mice then received CGP3466B. The scientists found that once they received CGP3466B, the addicted mice resumed spending equal time in both rooms, i.e., they were no longer addicted.
“What’s exciting is that this drug works at very low doses, and it also appears only to affect this specific pathway, making it unlikely to have unwanted side effects,” said researcher Dr. Risheng Xu at Johns Hopkins University. The study of CGP3466B also helped confirm the details of cocaine’s action and potential treatment options. (DrugFree.org)
Cocaine stimulates the neurotransmitter dopamine, which is a brain chemical that is responsible for controlling pleasure and seeking reward. Cocaine raises the level of dopamine in the brain and tricks the brain into thinking it was something positive that should be repeated. Chronic use of cocaine can cause down-regulation or even damage to neurotransmitter receptor sites, disrupting the brain’s natural chemistry. This leads to withdrawal symptoms, feeling of loss of control, anxiety, stress, depression, cravings, and deeper levels of addiction.
An addict’s abnormal brain biology may increase his or her risk of substance abuse relapse. Studies show that MRI-based neuroimaging research holds potential in identifying markers for this increase, as published in Alcoholism: Clinical & Experimental Research in June 2011.
At least 60 percent of individuals in recovery for alcohol abuse disorders relapse within six months of treatment. Because the reward system of the brain (BRS) has been “implicated in the development and maintenance of all forms of addictive disorders,” researchers of the neuroimaging study compared thickness, surface area and volume of neocortical components of the reward system of the brain. The study participants included three groups: light drinkers, alcohol-dependent individuals still abstinent after treatment, and those who relapsed. (Medical News Today)
The reward system of the brain (BRS) includes regions in the frontal and temporal lobes, limbic system, basal ganglia and other subcortical structures. These form a functional network which involves our experience and response to pleasure and aversion, mood regulation, higher-level cognitive abilities, such as problem-solving, reasoning, decision-making, planning and judgment, memory, as well as impulse control. It is believed that abnormal biology of the BRS may play a significant role in the development of drug and alcohol dependencies.
Researchers used magnetic resonance imaging (MRI) to examine the BRS and determine whether there were structural differences in the brain’s cortex for the three groups. The findings support the fact that neurobiological factors influence relapse. Of the two groups who suffered with alcohol dependency (abstainers and relapsers), their brain’s had significantly thinner cortices in the BRS and throughout the brain. Those who had relapsed showed showed the most substantial structural abnormalities in the BRS with lower surface area and volume than the abstainers and the control group. This may mean they have fewer brain cells and neural resources available to assist with recovery. (Medical News Today)
Another significant finding was that of those individuals who relapsed, the ones with the greater volume and surface area in several regions of the BRS had a less severe relapse.
Not only do neuroimaging techniques promote a better understanding of the neurobiological factors associated with relapse, but as this study shows, such methods can be useful in identifying addicts with the greatest degree of neurobiological abnormalities and thus the most at risk for relapse at the beginning of treatment. This can help predict who will benefit most from certain treatments and aftercare plans.
There is a definite link between genes and addiction and the level of a specific genotype can influence the severity of addiction. A study conducted at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory demonstrated that drug addicted individuals who have a certain genetic makeup have decreased gray matter density – and therefore fewer neurons – in areas of the brain that are essential for decision-making, self-control, and learning and memory. The research is reported in the March 7, 2011 issue of the Archives of General Psychiatry. Read more →
Researchers at Ohio State University believe they’ve found a genetic variant (characterized by one or both of two identified, tiny gene mutations) that is associated with a more than three times increase in susceptibility to severe cocaine abuse with the risk of fatal overdosing, compared to non-carriers of the genetic variant. (ScienceDaily)
This genetic variant was most common among white people with nearly one in five carrying the genetic variant. Among this group of people, one or both of the genetic variants were found in more than 40 percent of the autopsy brain samples from those known to abuse cocaine. This is compared to only 19 percent of those who lived drug-free and contained one or both of the genetic variants.
It was found that this genetic variant, one or both in combination, affect how dopamine functions in the brain. As we’ve discussed before, dopamine is a key neurotransmitter in the reward center of the brain, as well as numerous, regulatory functions of the central nervous system. Previous studies have shown that cocaine blocks dopamine’s reabsorption, leaving the chemical outside the brain cells and thus creates an artificial “feel-good” sensation.
This study found that in people who carry this genetic variant, the “function of a gene responsible for transmitting dopamine signals in the brain is altered” (Medical News Today). This led scientists to believe that this alteration can send neurotransmitters into a vicious cycle, including the development of cravings for an artificial substance, such as cocaine, that can maintain elevated levels of dopamine in the brain.
The study will soon be published in Neuropsychopharmacology. It has further opened the door to more questions about the involvement of the variant in initial use of the drug, level of cravings, and strength of the overall effect of the trait. It also suggests the need to explore how this variant could affect treatment for other psychiatric disorders involving dopamine.
