Addiction Impacted by Genetics

 Alcoholism is a genetic addiction that accounts for 40-60% of the risk. Opiate and cocaine addictions also have comparable heritability rates. Addiction susceptibility is linked to large chromosomal areas, although genetic variations are unknown. Alcohol sensitivity and acute alcohol side effects are increased in some East Asian groups due to enzyme polymorphisms that metabolize alcohol. Aldehyde dehydrogenase type2 homozygotes seldom develop alcoholism. Drug misuse affects inbred mice and rats differently. Identification of mouse lines carefully bred for alcohol or drug responsiveness should illuminate addiction pathways. Due to the intricacy of addiction and the possibility of variations in distinct genes causing addiction in different lineages, identifying genes that increase addiction risk is complex. Poverty, criminality, and delinquency impact risk, but their effects are unclear. Stress and genotype can also affect an animal's sensitivity to a substance of abuse, according to animal research. Investigating how genetic variants and environmental variables interact is crucial. Genetic and ecological variables impact an individual's initial drug sensitivity and how nerve cells and circuits adapt to prolonged drug exposure, which leads to addiction. Behavioral research emphasizes quantifying behavioral endpoints with the same complexity and interassay reliability as non-behavioral variables. Genes may modify the form or function of specific brain circuits throughout development or maturity or influence neural circuits influenced by environmental inputs, making them vulnerable to addiction. Genetic techniques and particular phenotypes may help identify addiction susceptibility genes in people and animals.

Animal models are absolutely necessary for elucidating the neurological workings of the addictive process. Nevertheless, genetic changes can occasionally result in traits for which there is no obvious explanation. It is now conceivable because of the growing sophistication of genetic techniques and the predictive value of animal models, to grasp the cellular mechanisms and neuronal circuitry linking chemical events with complicated behavior. This will allow for the completion of the puzzle, which was previously impossible.

Addiction is a broad term that incorporates a variety of maladaptive behaviors. These behaviors include use disorders for substances like alcohol, nicotine, cannabis, and cocaine, all of which significantly contribute to morbidity and death. In this overview, categorization, diagnosis, heritable variation, gene-based techniques, alternative genetic variations, gene-environment interactions, and pharmacogenomics are discussed. In addition to this, it explores how these methodologies might be applied to better understand the mechanisms that are at the root of nicotine addiction and to develop novel therapies.

https://www.nature.com/articles/ng1100_277 

https://www.nature.com/articles/tp201254 

Marijuana Addiction Linked to Genetics

Researchers are finding a possible link between certain genes and marijuana dependence. These three genes are also said to have an affect on risk factors for depression, which may mean that the two are linked together. In one study, 14,000 Americans provided information on marijuana use and 18-36% of people reported to be marijuana dependent. Given this information, researchers also looked for genetics variations that were linked to this. One genetic variant was located in a gene that regulates calcium concentrations in blood. Calcium has also been shown to have an affect on opioid dependence. Another one was located in the CSMD1 gene which has also been linked to schizophrenia. While these studies suggest that these genetic variants can lead to marijuana dependence, it is not proven. Further research is needed in order to have a better understanding of the addiction so that drugs can be made to help treat people who are dependent.

I found it interesting that the CSMD1 gene was also associated with schizophrenia, because I have heard that smoking a lot of marijuana can lead to psychiatric disorders, such as schizophrenia. It is important to be cautious about these drugs because no one knows whether or not becoming marijuana dependent is in their genes, so trying it one time can lead to a lifetime of addiction and complications. I also find it interesting that calcium signaling can lead to substance-abuse disorders, because it is not what I would expect. I would like to get genetic testing done so I can see what my risk levels are for these types of disorders as well as other health problems, because a lot can be determined simply from examining your DNA.

The Influence of Genes on Addiction

An article from the University of Utah Health Sciences Department, Genes and Addiction, discusses the role that genetics play on substance addiction. Genes are responsible for making an individual more vulnerable to substance dependence.  Research performed on laboratory mice has been helpful to determine the effects of similar traits in humans. When a certain gene was found to play a role in addiction in mice, the counterpart sequence of DNA was examined in humans.

I agree with the article that an individual’s environment is a much larger factor to addiction than genetics. If inheritance causes an individual to have higher withdrawal symptoms for a substance, but their environment does not put them in a position to experiment with this substance, then the genes would have no visible effect to the individual. However, if an addict has a genetic predisposition to have harsher withdrawal symptoms, than genetics could aid in the individual remaining addicted to the abused drug.

A goal of studying the genetic basis of addiction is to improve treatment for addicts. Identifying gene sequences that play a role in addiction allows scientists to develop drugs that are more effective in controlling this gene. This can begin a new wave of treatment, with drugs tailored specifically to your genetic make-up.

University of Michigan Professors to Study Genetics of Drug Abuse on Rats

           The affects and aftermath of drug and alcohol abuse are extremely prevalent in modern day society. The media is shedding light on this issue on a large scale, especially in contrast to previous decades. Thus scientists are feeling inclined to study this phenomenon on a biochemical level to attempt to understand why drug abuse occurs, and ultimately how science can be a remedy for this terrible social blight. 

           Two University of Michigan professors were awarded approximately 1.5 million dollars as a grant to study drug addiction and abuse on a small scale with rats. Terry Robinson, the Elliot S. Valenstein Distinguished University Professor of Psychology and Neuroscience, and Shelly Flagel, assistant professor in the Department of Psychiatry, were given the five year grant. 

           This grant was awarded from the National Institute on Drug Abuse. The two scientists will conduct studies to find out the basis for reward seeking behavior on a neurological level. This is the primary model that researchers are thinking will mimic human behaviors that correlate with substance abuse. Furthermore, the duo are looking for a genetic explanation as to why some people might be more susceptible to drug addiciton than others, and why some people who are trying to recover relapse back into their old vices. Although rats have different responses to stimuli than humans, this model is the best representation of an emulation of human drug abuse.

Main article: http://www.mlive.com/news/ann-arbor/index.ssf/2014/10/15m_grant_awarded_to_u-m_profe.html

Related information: http://www.freep.com/story/news/local/michigan/2014/10/13/university-michigan-rat-study-addiction-grant/17191173/

A Recent Study Identifies Schizophrenia as Eight Distinct Genetic Disorders

In a recent study on schizophrenia, researchers at the Washington University School of Medicine analyzed DNA of 4,200 patients who had been diagnosed with the disorder, as well as 3,800 individuals with no history of the disorder.  In the past, schizophrenia was thought of as a single mental disorder.  However, the results of this study indicate that schizophrenia is actually a group of eight prominent disorders.  Scientists grouped patients based on their symptoms.  The groups included the following: difficulty in connecting emotions, thoughts, and varying types of hallucination.  In previous studies on schizophrenia, scientists have focused on analyzing gene sequences, but have had a difficult time locating specific genes where the disorder originates. Researchers created genetic profiles by matching symptoms with each individuals unique genetic features.  It is important to note that symptoms range from mild to very severe.

Based on the results, it can be concluded that certain genetic profiles make people more susceptible to developing schizophrenia.  For example, results revealed that disorganized behavior and speech patterns were linked to a group of DNA variations that yield a 100 percent risk of schizophrenia.  Senior investigator Dr. Robert Cloninger stated, "Genes don't operate by themselves.  They function in concert much like an orchestra, and to understand how they're working, you have to know not just who the members of that orchestra are, but how they interact."  People with schizophrenia are commonly diagnosed in their 20s, which is when many symptoms begin to arise.  Schizophrenia effects approximately 1 percent of the population.  The chances of developing the disorder increase to 10 percent if a relative is diagnosed making schizophrenia highly genetic.  Researchers indicate that the environment is a huge risk factor for the disorder, including stress and substance abuse.

The image above compares the brain activity in a healthy 

person to that in a person with schizophrenia 

(red is intense activity, purple is very little activity)

Ultimately, the ability to predict high risk within genetic clusters is a giant step forward.  The goal is for doctors to one day be able to offer patients a more in-depth diagnosis, in which identifying risk would allow them to assist in early prevention.  Genetic studies of this nature open up future treatment possibilities of schizophrenia, which could lead to treatment based on pathways within DNA.  More importantly, DNA-based genetic research may be useful in the future in analyzing other hereditary diseases, such as heart disease and diabetes.  This article grabbed my attention immediately, as I was surprised that schizophrenia was comprised of so many genetic disorders.  It put into perspective why many diseases and disorders are so hard to treat.  Many disorders lack a single genetic disorder to target.  Instead researchers are responsible for finding the best treatment that targets all of the genetic disorders as a whole.  I find it fascinating how researchers continue to develop new treatment methods regardless of the obstacles they are faced with.

[1] Article:http://www.newsweek.com/schizophrenia-actually-eight-distinct-genetic-disorders-according-new-study-271407

Related articles: http://www.medicalnewstoday.com/articles/282539.php

                           http://punnett.blogspot.com/2014/09/schizophrenia-is-eight-different.html
                           http://punnett.blogspot.com/2014/09/a-research-team-at-washington.html

The Science of Addiction

The number of drug users in the United States today is over 15 million according to the World Health Organization (WHO). This astonishing statistic grows daily along with the amounts of drugs that are used. The lost path of the users at one point matched the lost path of the scientists looking for answers about addiction. Within the past decade, studies have increased in finding specific genetic information in regards to drug addiction. There are currently 11 chromosomes that have connections to substance addiction. In addition, there has been a connection with addiction in certain genes as well including GABRA2, ANKK1, neurexin 1, neurexin 3, and aldehyde dehydrogenase. These chromosomes and genes that have been studied display a connection amongst more than one specific substance. For future studies, scientists hope to find more information on the genes connected to this issue as well as the nature of each of them.

The use of genetics in addiction studies could help to eliminate these upsetting statistics. In the future, scientists could use these genes connected to addiction in order to help find better treatment options. Currently, many treatment options are pharmaceuticals that are not fixing the solution as addicts are still able to manipulate these drugs. Through the isolation of these genes, hopefully more natural cures could be found as well as preventative options for those predisposed to powerful substance addictions.

http://www.sciencedaily.com/releases/2009/03/090310142912.htm