Schizophrenia and Dopamine Hypothesis

Schizophrenia and Dopamine Hypothesis

Yale Alexia Abnormal Psychology 2013FA-PSY-241-1 Tuesday/Thursday 9a. m. 10/9/13 Schizophrenia And the Dopamine Hypothesis INTRO “Men will always be mad and those who think the can cure them are the maddest of all. ” (Volaire, 1759) Schizophrenia, aka the cancer of psychology, has become a vast mystery for psychologist. It accounts for 80% of long-term hospital stays. Even with the conveniences of modern technology we still have yet to be able to discover the true cure for the disorder.

There are several unique biological, environmental, and developmental factors that help influence the likelihood of obtaining Schizophrenia. One major influence making its way into spotlight is Dopamine. Multiple studies have shown that an abnormal level of the neurotransmitter Dopamine can indeed be related back to a significant increase in one’s likelihood of being diagnosed with Schizophrenia (Creese, Burt, Snyder, 1976). Thus creating the dopamine hypothesis. There are numerous facts that help support the dopamine hypothesis as a significant cause to being diagnosed with Schizophrenia.

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The main supporting factors for the dopamine hypothesis include evidence from illicit drug use, neuroimaging, and a roup of drugs called phenothiazines. DEFINED Schizophrenia is a mental disorder in which your personal, social, and occupational lives deteriorate as a result from its characteristics that lead to a breakdown of cognitive, emotional, and motor responses. Symptoms of Schizophrenia usually begin to appear during young childhood. The most common symptoms are delusions, hallucinations, disorganized thinking/speech, social withdrawal, and loss of motivation and Judgment.

There are three different categories that symptoms can be classified into: positive symptoms – symptoms that appear to be in excess of ehavior, emotion, and/or bizarre additions to normal thoughts; negative symptoms – symptoms that are in deficit when compared to normal thoughts, behaviors, and emotions; and lastly psychomotor symptoms – symptoms dealing with unusual movements or gesturers. Both positive and negative symptoms are typically common, however, one or the other types will typically dominate patients (Keefe & Eesley, 2012).

ETIOLOGY The etiology of Schizophrenia is commonly attributed to genetics, but environmental factors such as, developmental complications and drug use, that also influence the occurrence rate. Finding an individual’s main cause of the disorder can often prove challenging because of the difficulty in telling the separation between the effects of genetics and the environment (Picchioni, Murray, 2007). Having a first- degree relative will set you at a 6. 5% chance of being diagnosed with the disorder. It is thought that there is most likely numerous genes that go into play when it comes to Schizophrenia.

There are no known major affecting genes that cause this disorder, but more likely a number of genes with their own small effect and unknown expression. This creates much difficulty when trying to pinpoint the specific related enes (McLaren, Silins, and Hutchingson, 2010). It is believed that people with Schizophrenia are more likely to be born during the winter or spring, if they live in the northern hemisphere. This is thought to be because, while pregnant, Mother’s are put at an increased risk of viral exposure to the womb, by things such as infections and hypoxia.

Stress and malnutrition can also lead to a slight increase in the risk of the development of Schizophrenia later on in life. As either a child or an adult living in an urban environment, especially when living in poverty, has been found to largely increase your chances of being diagnosed ith this disorder. Having a positive social life and living with supportive parents has been shown to increase the overall well being of the patient (Picchioni, Murray, 2007). The last major factor that influences the diagnosis of Schizophrenia is drug use. Around half of the people who are diagnosed with Schizophrenia also use and abuse drugs and or alcohol.

Amphetamines, cocaine, and marijuana are thought to be the major contributors (Picchioni, Murray, 2007; McLaren, Silins, and Hutchingson, 2010). These drugs especially, are associated with the dopamine hypothesis, which will be iscussed later on in greater depth. Other drugs, such as alcohol, may possibly be used as Just a way to cope with the depression, boredom, and loneliness that often follow along with the disorder. RATE/INCIDENCE Approximately 1% of the world’s population is affected by this disorder. That means over 24 million people worldwide have had Schizophrenia at some point in their lives (Van Os J & Kapur S, 2009).

However, this rate can vary up to threefold according to geographical location. It is 1. 4 times more likely to occur in males than females and usually appears earlier in life for men. People who have biological elatives are at a heightened risk of obtaining Schizophrenia (Coon & Mitterer, 2007). Having an identical twin or being the child of two parents with the disorder puts you at an 46%/48% chance of developing the disorder. DIANOSIS Observing one’s behavior, as well as listening to the patient’s past reported experiences, is the most common method of diagnosis.

According to the DSM-Vto be diagnosed with Schizophrenia, over a one-month period, you have to experience at least two separate symptoms long enough to become abnormal. At least one of these symptoms has to be delusions, hallucinations, or disorganized speec h. In the evelopment of Schizophrenia there are three different stages: acute, residual, and prodromal stage (Barnett, 2009). The first stage of Schizophrenia is the prodromal stage. This stage refers to the year before the illness appears in which people start showing signs of the disorder.

Often they start to isolate themselves from friends and family and have decreased motivation or bunted emotions. The second stage is the acute stage. In this stage someone will start experiencing psychotic symptoms such as hallucinations, delusions, or overly disorganized behavior. This stage shows that the person has fully development the disorder. The third and final stage is the residual stage. This stage is very similar to the prodromal stage. People who are in this stage do not appear psychotic but they may still have strange beliefs and or other negative symptoms such as low energy or lack of emotions (American Medical Network, 2009).

TREATMENT To help manage Schizophrenia patients are most often prescribed antipsychotic medications, usually along with psychological help and social support groups (Van Os J, Kapur S, 2009). Since the 1950’s, when deinstitutionalization came about, long hospital stays have largely become a thing of the past, although sometimes they do till occur; which depending on the severity of the disorder, can be either voluntary or involuntary. Most antipsychotics reduce the positive symptoms in around 1-2 weeks. So that will get rid, or at least help control, all of the extra crazy sights and sounds.

However, there is no significant improvement when it comes to the negative symptoms as well as most of the cognitive dysfunctions (Tandon, Keshavan, Nasrallah, 2008). As long as the patient stays on the medication they should have a largely decreased chance of relapse. Beyond 2-3 years research shows that the antipsychotics may become inconsistent with the significance of the benefits. Based on the costs, benefits, and risks of the medication, a person diagnosed with Schizophrenia would be prescribed with one of two different classes of antipsychotics; either typical, or atypical antipsychotics.

Both classes have an equal dropout and relapse rate so it is very debatable as to which class is better than the other. As with many major medications there are separate negative side effects that are associated with the two classes. Antipsychotics in the typical class, such as Haldol, Thorazine, and Prolizin, often have a high rate of extrapyramidal side effects; he major one being tardive dyskinesia (TD)- causing involuntary movements most often affecting the facial region. Patients may not even notice these movements.

The newer medications in the atypical class, such as Abilify, Risperdal, and Seroquel, have a much lower risk of TD, but patients will often have a significant increase in body weight gain. Also, if given at too high of a dosage, patients may experience social withdrawal as well as have body tremors/movements that get very close to resembling Parkinson’s disease (National Institute Of Mental Health, 2006). PREVENTION Schizophrenia is a disorder with no reliable distinctions for the development of the disease (Cannon, Comblatt, Mcgorry, 2007).

This creates an issue for early detection and prevention. There is indecisive evidence as to the effectiveness of early interventions to prevent Schizophrenia (Marshall, Rathbone, 2006). While still in the prodromal phase, it is uncertain that attempting to prevent Schizophrenia is of any benefit and therefore as of 2009 is not recommended. After a year, cognitive behavioral therapy is able to decrease the chance of psychosis in those patients that re of high risk of obtaining the disorder (Stafford MR, Jackson H, Mayo-Wilson E, Morrison AP, Kendall T, 2013).

Another preventive measure, that is widely accepted, is staying away from drugs that are thought to be able to cause the disorder, such as meth, coke, and marijuana. This preventive method is also known as the “Hugs Not Drugs” method (Hugsnotdrugs. com, 2013). PROGNOSIS Schizophrenia can become extremely disabling. Being ranked as the 3rd highest disabling condition in the world, placing Schizophrenia higher up on the list than blindness and paraplegia (Ustun, 1999). Studies have shown that people who are iagnosed more at risk to commit suicide. However, this higher risk of suicide is not significant being as low as only 4. % most likely; most commonly occurring at the beginning of facilitation when they are undergoing extreme stress (Hor k, Taylor M, 2010). Although life expectancy has increased in recent decades, people with Schizophrenia on average have a 12-15 year decrease in life expectancy compared to the normal population. There are three major factors that contribute to the lower life expectancy: a lazy/low activity life style, obesity, and smoking cigarettes (Van Os J, Kapur, 2009). Of people diagnosed with Schizophrenia, about % have a continuing disability and problems with relapses.

About 17 million people in the world are living with a moderate or severe disability from the disorder. However there are patients that do recover completely and many others are still able to function well in everyday society. Very often people with Schizophrenia are also heavy smokers. Anywhere from 80-90% of Schizophrenic people smoke cigarettes. This is very significant compared to the 20% of people who smoke from the general population. When Schizophrenic people smoke, they tend to smoke very heavy and hard as well as ypically only smoking cigarettes with high nicotine content (APA, 2002, pg. 304).

Excess tobacco smoking will of course lead to a higher health risk that contributes to the lower life expectancy. There has yet to be an exact solid answer as to why Schizophrenic people more commonly smoke cigarettes. DOPAMINE & D2 The Dopamine hypothesis is a model that states that certain factors, which of whom have been known to create abnormally excessive levels of the neurotransmitter dopamine, have been linked to a significantly increased risk of being diagnosed with Schizophrenia. These abnormal levels of dopamine result from eurons firing too often that make use of dopamine as a neurotransmitter.

This causes an uneven shift in the two-way communication within the brain, and sends too many messages at once, in turn producing symptoms that are common to Schizophrenia (Grace, Abi-Dargham, 2011). As more and more studies are being completed, this hypothesis is continuing to provide an evolving basis to help psychologists understand as to how this disorder originates, and how to create better treatments for patients. This theory however, does not solely hold excessive dopamine levels as an absolute and complete explanation for Schizophrenia.

The ver activation of the D2 receptors seem to also be a widespread effect of abnormal chemical synapsis. This theory obtained further support during the mid-1970’s when Creese made the connection that antipsychotic drugs had a significant ability to block dopamine D2 receptors (creese, Burt, snyder, 1976). METHAMPHETAMINES In recent decades Amphetamines, especially crystal meth, have become widely popular with the more deviant of our societies. There are of course many negative repercussions that affect one’s health with the abuse of methamphetamines.

The worst of which, is methamphetamine’s highly addictive properties. When dministered Methamphetamine at significant dosages, the drug becomes neurotoxic specifically to dopamine neurons (Cruickshank, Dyer, 2009). The connection wasn’t made until 1966 when Rossum proposed that the hyperactivity of dopamine transmission could responsible for the disorder of Schizophrenia (Rossum, 1966). Rossum also looked back a few years and used Carlsson and Lindqvist’s research on mice, finding that dopamine plays an important role in the functioning of the extrapyramidal motor system (Carlsson, Lindqvist, 1963).

In a study that reviewed hospital records of patients, that were diagnosed with drug dependence/abuse, and dmitted between 1990-2000, they found that people who were hospitalized for methamphetamines had 1. 5-3x more likely chance of being diagnosed at the end of the study with Schizophrenia (Wood, 2011). This statistic of diagnosis being up to 3x more likely to occur with meth use should alone be able to make the effects very noticeable. Since methamphetamines create an influx of dopamine levels, you can easily make the connection that dopamine and Schizophrenia are closely related.

During an interview in 2004, Dr. Heather Keizer, a psychiatrist, referred to methamphetamine as the “on switch” for Schizophrenia (Cudworth, 2005). She also described how even after they (the clinicians) could get the patient cleaned up, and eliminate the drugs from their system but theyd still be psychotic. Often within the year she would diagnose them with Schizophrenia. Again this provides substantial evidence that methamphetamines effect on dopamine is responsible for numerous diagnosis of Schizophrenia.

CANNABIS Cannabis has a similar affect on dopamine levels, in turn making it plausible to relate the use of the drug to Schizophrenia. The percentage of people who have been diagnosed Schizophrenia and make use of cannabis is higher than that of the eneral population (Lynch, Rabin, and George, 2012). A whopping 25% of patients with Schizophrenia can be diagnosed with either cannabis abuse or dependence. Information from several cohort studies provided addition evidence of dopamine’s link to Schizophrenia. Their findings showed that when compared to nonusers, people who used cannabis had a 40% more likely chance of psychosis.

This risk was also dose-related, showing that psychotic symptoms had up to a 200% increased chance of appearing in users who made use of cannabis on the regular (Lynch, Rabin, and George, 2012). Again this goes to show that drugs affecting dopamine levels have a significantly obvious relation to an increase in diagnosis of Schizophrenia. If we look at the classical study, started in 1969 of a little more than 50,000 Swedish conscripts, we can have a glimpse at some of the more extreme links cannabis has to Schizophrenia.

They found that if you used cannabis more than 50 times, you were nearly SEVEN times more likely to eventually develop Schizophrenia (Andreasson, Allebeck, and Rydberg, 1987). This statistic shows how even a small cannabis consumption can have adverse effects and has more than enough power to shock ny associate of mine that regularly uses cannabis; as well as making them prone to question thetr sanity. PHENOTHIAZINES Phenothiazines are the largest of the five 5 major classes of neuroleptic antipsychotic drugs. Theyre known for their antipsychotic properties and are often associated with severe side effects.

These antipsychotics have been found to antagonize dopamine binding, specifically at the D2 dopamine receptors (Creese, Burt, and Snyder, 1976). This effect causes a reduction in the positive psychotic symptoms that people with Schizophrenia experience. So yet again you have a substance influencing Schizophrenia by affecting the brain’s dopamine receptors. These findings lead to the eventual usage of other antipsychotic classes that included drugs such as Haloperidol. Patients with Schizophrenia are almost always treated with a prescription of antipsychotics, and why is that?

Because they work; and the reason they have been proven effective at combating the symptoms of Schizophrenia is because they influence and block dopamine receptors. Which of course helps support the legitimacy of the dopamine hypothesis. NEUROIMAGING Neuroimaging is used as a research tool to measure certain aspects of the brain nd specific mental functions. This comes in use when observing the effects of drugs on the brain. This method came about in the early 1980’s and made many improvements on our knowledge of how substances affect our body.

This came in use in providing evidence for the dopamine hypothesis, when it was used during a study done in 1986. By comparing neuroimages of a normalized control group to that of people diagnosed with Schizophrenia, they were able to indicate to effects of amphetamines on the brain. They found that people diagnosed with Schizophrenia had increased levels of dopamine, especially in the striatum, when compared to non- sychotic individuals Oacobs, Silverstone, 1986). These images prove that over activity of dopamine is directly linked to being diagnosed with Schizophrenia.

CONCLUSION Schizophrenia is an extremely damaging disorder, in which psychologists still have much to learn about the etiology and treatments. In the United States alone, the disorder cost the country nearly $63 billion in 2002 (Wu Eq, 2002). In recent decades studies have conclusively shown that excessive activity in D2 receptors is definitely associated with the onset of Schizophrenia. Support for the dopamine hypothesis is idely shown and proved by studies done on illicit drug use, and the class of drugs called phenothiazines, as well as the development of neuroimaging help provide substantial evidence.

With this vast amount of factual information, it is hard to argue against the legitimacy of the dopamine hypothesis. Lastly, the reoccurring motif that you should take home if you want to avoid becoming Schizophrenic is: Don’t do drugs. WORKS CITED Cudworth, Laura. “Crystal Meth and Schizophrenia. ” Schizophrenia. com. Schizophrenia Daily News Blog, 6 July 2005. Web. 27 Oct. 2013. Wood, Janice. “Heavvy Meth Use May Up Risk of Schizophrenia I Psych Central News. Psych Central. com. PsychCentral, 9 Nov. 2011. Web. 27 Oct. 2013. Freeman, David. “Methamphetamine Tied to Schizophrenia. ” Cbsnews. com. CBS News, 8 Nov. 011. Web. 27 Oct. 2013. Comer, Ronald J. Fundamentals of Abnormal Psychology. New York: Worth, 2014. Print. Keefe & Eesly, 2012, Neurocognitive Impairments. J. A. Lieberman, T. S. Stroup, & D. O. Perkins, Essentials of Schizophrenia. Arlington, VA: American Psychiatric Publishing. Diagnostic and Statistical Manual of Mental Disorders: DSM-5. 5th ed. Washington, D. C. : American Psychiatric Association, 2013. Print. Van Os, J. , and S. Kapur. “Schizophrenia. ” NCBI. U. S. National Library of Medicine, 22 Aug. 2009. Web. 27 Oct. 2013. “Voltaire. ” Goodreads. com. Goodreads, n. d. Web. 28 Oct. 2013. Coon, D. Mitterer, 1. 0. (2007). Introduction to Psychology: Gateways to Mind and Behavior (1 lth ed. ). Belmont, CA: Wadsworth. “Stages of Schizophrenia. ” Health. am. American Medical Network, 11 May 2009. Web. 25 Oct. 2013. Cannon TD, Cornblatt B, McGorry P. The empirical status of the ultra high-risk (prodromal) research paradigm. Schizophrenia Bulletin. 2007 Marshall M, Rathbone J. Early intervention for psychosis. Cochrane Database of Systematic Reviews. 2006 Stafford MR, Jackson H, Mayo-Wilson E, Morrison AP, Kendall T. Early interventions to prevent psychosis: systematic review and meta-analysis.

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National Center for Biotechnology Information. U. S. National Library of Medicine, 29 Apr. 2009. Web. 02 Nov. 2013. Carlsson A, Lindqvist M. Effect Of Chlorpromazine Or Haloperidol On Formation of 3Methoxytyramine and Normetanephrine In Mouse Brain. Acta Pharmacol Toxicol (Copenh) . 1963 Jan 1. Nov. 14. 2013. Rossum. “Significance of Dopamine-receptor Blockade for the Mechanism of Action of Neuroleptic Drugs. ” PubMed. gov. U. S. National Library of Medicine, Apr. 1966. Web. 13 Nov. 2013. Abi-Dargham, and Grace. “20. Dopamine and Schizophrenia. ” Onlinelibrarywiley. com. Wiley Online Library, 8 Mar. 2011.

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