Substance Use and Abuse - Essay Example

Substance Use and Abuse s Introduction People experiment with drugs for varied reasons. People may try out drugs for the first time for recreation, out of curiosity, peer pressure, to enhance athletic performance, or solve a problem, like depression or stress. However, the use often does not result in addiction, yet addiction only comes about due to repetitive use. The risk factors for addiction are biological, social, and environmental. World Health Organization estimates that about 37% of persons aged 16-59 use illicit drugs, with the highest number being reported young adults aged below 25 years. An estimated 2 billion people use alcohol and other substances. An estimated 500 million are addicted to drugs and alcohol. Addiction is a condition that comes about as a result of a person ingesting substances such as alcohol, nicotine, morphine, and cocaine among others or being a participant in an activity that is pleasurable to the extent that it becomes compulsive, and interferes with a person’s ordinary life roles and responsibilities. However, some individuals are able to use substances and not incur the negative effects or even be addicted. As for the many others, substance use and abuse results in problems at school, work, and homes, as well as in relationships. Therefore, drawing on a variety of sources the paper will discuss the reward circuits thought to underpin substance use and abuse. Furthermore, the research paper will evaluate the factors that lead to addiction and eventually give a conclusive summary on which factor appears more responsible for addiction. Discussion Even though all drugs have various psychological and physical effects, all abused substances have one thing in common; continual use alters the manner in which the brain functions. If one takes recreational drug, it causes an increase in the dopamine levels triggering a feeling of pleasure (Malenka, Nestler, & Hyman, 2009). The brain remembers this feeling and wants them again. The same effect is demonstrated when one uses illicit drugs (Pickens & Svikis, 2009). The uncontrollable craving grows because the brain is used to being triggered by ingestion of certain substances. Therefore, one starts experiencing problems because of the changes in the functioning of the brain interfere with one’s ability to think, control their behaviour, perform good judgement, and a normal feeling without drugs. Addiction can be understood purely within biological terms based on the reward system. According to Kendler et al. (2012), a reward is usually an appetitive stimulus that is given to living organisms, especially humans and animals with an aim of changing their behaviour. Volkow (2004) adds that a reward enhances the probability of behaviour. In the reward circuits, the drugs of abuse often target the pleasure centre of the brain as shown in the figure 1 below. The brain structures that are responsible for enabling one to have that feeling of pleasure after taking drugs include the: anterior cingulated cortex, prefrontal cortex, ventral tegmental area, dorsal striatum, ventral striatum, insular cortex, hypothalamus, hippocampus, and amygdala (Grall-Bronnec & Sauvaget, 2014). Figure 1: Brain’s pleasure centre (Kendler, et al., 2012). The core of the reward system is the basal ganglia circuit, with specific focus to the mesolimbic pathway (Abraham & Bear, 2006). In the same way, there are other brain components as well as circuits that exist, including anterior cingulated cortex together with midbrain dopamine pathways, respectively (Spooner & Hetherington, 2011). The cerebellum is also responsible for drug abuse (Holstege, et al., 2011). In the brain, the key neurochemical pathway is the mesocorticolimbic pathway that comprises of mesocortical along with mesolimbic pathways (Di Chiara et al., 2010). These pathways produce dopamine that is responsible for addiction. The source of the dopamine pathways in the brain is the ventral tegmental area and connects to the nucleus accumbens (Bonci & Malenka, 2009). Peter Milner and James Old taught rats of the manner in which to run mazes and solve problems by stimulating particular areas of the brain. The stimulation was found to give the animas pleasure. They attempted a similar thing to humans and the results were the same. The researchers concluded that dopamine assisted in the neuro signalling of the barin regions to create pleasure (Pierce & Kumaresan, 2006). The ventral tegmental area is made up of dopaminergic and glutamatergic neurons (Brebner et al., 2005). The ventral tegmental area communicates with the nucleus accumbens by means of the medial forebrain bundle (McFarland, Lapish, & Kalivas, 2011). The nucleus accumbens is made of medium spiny neurons, and it is located in the ventral striatum. It is further categorised into motor and limbic sub-regions (Ping et al., 2008; Maze et al., 2011). As cited by Zhang, Maldve, and Morrisett (2006), the medium spiny neurons get signals from the dopaminergic neurons of the ventral tegmental area as well as the glutamatergic neurons of the medial prefrontal cortex, amygdala, and hippocampus. These inputs activate the medial spiny neurons releasing the GABA into the ventral pallidum (Van den Heuval & Pasterkamp, 2008). The mesocorticolimbic dopamine is crucial in the rewarding properties of stimulant drugs, like amphetamines and cocaine (Koob, 2007). When someone takes heroine, amphetamines, cocaine or any other opiate, it travels via the bloodstream to the brain. The chemicals in these drugs are attached to certain specialised proteins on the surfaces of the brain cells. The connection of these chemicals with receptors triggers a similar biochemical process in the brain that rewards the person with a feeling of pleasure (Kenny, 2007). As evidenced earlier, one of the brain circuits that is usually activated by drugs is the mesolombic reward system. The system generates signals in the ventral tegmental area resulting in the release of dopamine in the nucleus accumbens. The release of dopamine into the nucleus accumbens results in a feeling of pleasure. The brain records a lasting memory of the pleasurable feeling and would produce similar results if a person encounters a similar situation (Kenn, 2007. As a consequence, these neural mechanisms explain why people use and abuse substances. Drugs of abuse are thought to initiate the involuntary signals that come from the amygdala, that are presumed to hijack the goal-driven cognitive control that is needed for normal operations of the prefrontal cortical system (Dumont, et al., 2005). These anomalies facilitate the progress of drugs of abuse. From here, the consequent excessive utilisation of drugs is aggravated perpetuating an addicted state (Muller & Unterwald, 2005). There are neurons that make use of the dopamine neurotransmitters. A reduction in dopamine amount has been linked with depression (Herbert, Herbert, & Pauli, 2011). It has been found that drugs, such as heroin, cocaine, and alcohol increase dopamine levels, resulting in a ‘feel good’ state (Kalat & Shiota, 2011). The dopamine neurotransmitters then transport the signs to other structures (Bjork et al., 2011). As a result, the addicts are often incapable of exerting adequate control over their drugs urges as well as their drug seeking and drug-taking behavior, even when faced with adversity. According to the World Health Organization (2014), most of the drugs addicts range from teenagers aged 16 to adults aged 59 years. However, those aged 25 years and below and reside in the urban areas have largely been reported to use illicit drugs. Globally, about 2 billion people use alcohol and other substances. Correspondingly, over 80% of substance users and abuers are found in Europe. Addiction is a complex disorder that is associated with compulsive use of the drug (Nestler, 2013). Agar and Reisinger (2010) further claim that it results in negative emotional states like anxiety and irritability. The symptoms of addiction, as noted by Zapolski, Cyders, and Smith (2009) include powerful cravings, tolerance, and compulsions. Repeated use of drugs changes the ability of the body to adapt to the availability of these substances. However, as the effect of the drugs reduce, the person may experience withdrawal symptoms, such as anxiety, bad temper, trembling, insomnia, hallucinations, seizures, nausea, vomiting, irritability and violence, bitterness and resentment, depression, loss of appetite and headaches. Depression is caused by a reduction in dopamine levels that makes someone look lively and enjoyable. One experiences anxiety, anger, and violence because the dopamine has not been released into the prefrontal cortex, amygdala, and septum. Biological factors Biological explanations share the view that the reward circuits make people experience pleasure by using drugs. There are various biological theories that explain this concept of addiction. The neurobiological theories of addiction argue that dopamine is released due to naturally rewarding experiences such as abuse of substances and sex. The biophysiological theory outlines that the psychoactive effects change the neuronal activity of the brain. The drugs interfere with the functioning of the neurotransmitters resulting in the abuse of drugs. The genetic theory explains addiction in terms of genetics and biochemical patterns. Recent studies have demonstrated that the genetic composition of a person plays a role in addiction. To purely understand addiction within the biological terms, the addiction biological models put emphasis on the significance of genetic and biological forces (Horvath, Misra, Epner, & Cooper, 2015). Based on the biological models, every individuals unique genetic composition and physiology results in an addiction. People often tend to use and abuse substances due to their genetic vulnerabililty. Pickens and Svikis (2009) share the evidence that it is valuabe to examine the family history along with genetic history, in relation to substance use and abuse. Various studies have come to a conclusion that the risk of developing substance use and addiction can be inherited. In other words, if there is a family member with an addiction, there are increased chances of one developing addictive behaviour. Alcoholism together with drug abuse tend to run in the same families (Harden, Hill, Turkheimer, & Emery, 2010). The people usually inherit genes that make the person have a feeling of pleasure when using and abusing drugs. The biochemical patterns in the mesolombic reward circuit makes them to experience and not forget the pleasure after using the drug. The genetic make up of a person is beyond their control. As a consequence, one can only control behaviour. Chassin et al. (1999) argue that behavior is influenced by genes. There are numerous genes that are responsible for substance addiction (Cadoret et al., 2005). For example, an individual may inherit a sociopathic personality that is often associated with increased possibility of contact along with experimentation with drugs (Horvath, et al., 2015). The genetic influences have been found to account for over 60% of the risk factors of becoming an addict (Newman et al., 2008). Tobacco use and opiod dependence have been shown to notably heritable (Cadoret et al., 2005). The inherited differences are found in the receptors for the brain cell for opiods together with in the enzymes which breakdown opioids (Bierut et al., 2008). Furthermore, the genetic link appears to be stronger between sons and fathers in comparison to mothers and daughters (Briggs & Pepperell, 2010). An addiction to marijuana, cocaine, and heroine seem to be more affected by genes in contrast to alcohol (Okan, 2005). Particular genes make people to be more addicted, generally. They often have an excitement of substance use and use. A person who has a parent who has an addiction is more vulnerable to addiction (Johnson & Leff, 2004). Even if the addiction is not passed to the immediate member, it may be passed in the family in the future generations. A study conducted by the New York University Langone Medical Center found out that individuals who have parents who are substance addicts are 3 to 4 times more probable to become-substance dependent in contrast to a person who does not have a family member with a substance use and abuse problem. Tsuang et al. (2006) found out that if a gene is not present, the protein that is tasked with controlling the functions of the physiology system may not be produced. As a result, one will not develop addictive behaviours. Kendler et al. (2011) have evidenced a relationship between alcohol and drug abuse and a gene that controls the number of dopamine receptors in the brain. The presence of a gene leads to a change in the brain dopamine pathway that usually contributes to substance use and abuse. Hicks et al. (2004) observe that even though genes have been shown not to be the only determinants of drug dependence, their presence or absence increases the probability that an individual will become an abuser of alcohol and other drugs. As a result, genetics play a major role in the drugs of abuse addiction. Bernard and McKeganey (2004) cite that the levels of addiction vary from one individual to another. The drugs exposure may have a significant effect on a person who carried genetic susceptibility to drug dependence as compared to somebody who does not. Partially, this provides an explanation as to why most of those who have experimented with drugs at a certain point in their lives do not become dependent. Some people have a genetic predisposition to become addicts. Their nervous system usually reacts very strongly to the ingested substance (Harden et al., 2010). As a result, it leads to an increased release of hormones like dopamine. As evidenced in the work of Pickens and Svikis (2009), dopamine is a crucial element to the rewards circuits inside the brain. Therefore, when the person takes the drugs of abuse it causes the dopamine to be released making them to feel good and crave for the repeat of the activity (Bear, 2006; Pickens & Svikis, 2009). Equally important, Kendler et al. (2012) claim that genes affects a person’s tendency to develop drug addiction. Genes impact on the person by means of production of idiosyncratic or aberrant biological response to drugs. For instance, genes may make an individual more or less responsive to the effect of drugs (Trantham-Davidson et al., 2004). To better comprehend addiction purely within biological terms, FosB is a gene transcription factor that is common in almost all forms of addictions: drug addictions and behavioural addictions (Zhang, Maldve, & Morrisett, 2006). FosB is overexpressed in the D1-type medium spiny neurons of the nucleus accumbens. The effect of its overexpression in the nucleaus accumbens results in an induction of an addictive state combined with behavioural addiction that occurs in addiction (Zachariou et al. 2006). As an example, the behavioural plasticity that is modulated by FosB is drug self-administration (Thomas, Kalivas, & Shaham, 2008). Most substance abusers when they have the craving for injectable drugs, they often administer to themselves (Dumont et al., 2005). In the same way, a researcher at Cambridge University announced the discovery of a biological initiator in the brain that makes individuals to switch from infrequent use to compulsion and addiction of substances (McBride, 2015). McBride’s study evidences that the switch from occasional use, to compulsion, and then addiction happens when one’s control for the desire of a drug moves from the ventral stratum of the brain that is associated with pleasures to the dorsal stratum that is linked with habit development. Therefore, drug addiction is linked to a change from impulsive to compulsive behaviour. However, genes can cause drug addiction when it interacts with other factors, such as the environment, psychological, and socio-economic issues. Environmental factors According to the exposure theories, addiction may be attributed to the reinforcement of drug administration. A person may not inherit the genes for use and abuse of substances, but lives in an environment that promotes substance abuse behaviour (Kendler et al., 2012). For example, a child may develop drinking habits because the parents, peers, and other people he or she interacts with also drink. There is a correlation between the environment and genes when it comes to the development of addictive behaviour. People who are genetically predisposed to getting are considerably at risk of addiction if they are in an environment where the drug they crave for is available (Rehm et al., 2009). Contrarily, there is overwhelming evidence that the environmental factors play a major role in developing in addition to continuing substance use and abuse (Amani et al., 2005). The frontal parts of the cerebral cortex, which includes the medial prefrontal cortex in the mesolimbic reward circuit is responsible for controlling choices in the environment (Kosten, 2008). For example, the rate of drug use and abuse is high among college students who reside in fraternity houses because drugs are readily accessible and heavy use is considered as normal (Pickens & Svikis, 2009). As a result, one may develop an addiction as a result of the environment. Therefore, the brain’s hippocampus and amygdala record a lasting memory of the the good feeling when one takes drugs and the circumstances, as well as the environment in which they occur. These memories, known as conditioned associations, often direct to the craving for drugs whenever the abuser re-encounters the environment, people, things, or places driving the abusers to seek out for more drugs. Mental health or psychological factors Another important factor in drug use and abuse is the amount and quality of emotional social support a person receives (Spooner & Hetherington, 2011). People who experience acute depression, anxiety, and trauma, plus other disorder are more at risk for developing substance use and abuse problem (Enosh et al., 2010; Field & Powell, 2007). Also, persons with mental disorders are likely to use and abuse drugs, especially those with anxiety and depression disorders. In the mesolimbic reward circuit, depression is associated with reduced or inadequate dopamine levels. Therefore, a person will use and abuse drugs in an effort to eliminate the depression. The substance exaggerates the dopamine levels reducing the depression and creates a good feeling. The hippocampus and amygdala store this experience and an in individual will continue to use and abuse drugs when depressed. A study by Murphy, Taylor, and Elliott (2012) explain that this is attributed to the fact that the substance often makes them feel better for a while and lessen the distress feelings. Schuckit (2006) observes that the repetitive use may lead to addiction so that to continue feeling better and recapture the fleeting pleasurable state. About personality traits, people with emotional problems have higher chances of using and abusing drugs (Ochsner & Gross, 2005; Quirk, 2001; Verdejo-García et al., 2007). Evidence points out that such individuals have a genetically determined brain disorder involving the prefrontal lobes (Kenny, 2007). Therefore, the substance abuse not only creates psychological problems for the addict, but also creates problems for their families (Pourmovaheda, Yassini, Dehghani, & Askari, 2013), for instance, the development of suicidal behaviour (Sihnola et al., 2008). Cheetham, Allen, Yücel, and Lubman (2010) conducted a study on if negative mood increased the urge for drugs. It was reported that the most reactive people were those with the highest levels of depression and anxiety. These persons were also the most expected to be motivated to consume alcohol and use drugs by negative emotional states. It can be concluded that there is a clear connection between substance use and abuse and affective psychopathology. Altman et al. (20099) affirm that most people who have stress occasionally use drugs as a way of relieving the stress. On the other hand, some of them develop addictive behaviour because they have a genetic predisposition to addiction. Social factors Substance use and abuse is common among teenagers as well as young adults who may experiment with psychoactive substances (Jafari et al., 2009). The most commonly used and abused drug among the youth is cannabis (Fergusson, Horwood, & Beautrais, 2003). Also, people from low socio-economic backgrounds are more likely to use and abuse drugs (Spooner & Hetherington, 2011; Mohan, et al., 2005). This shows the role social factors play in use of drugs of abuse (Cunha et al., 2011). Verster, Brady, Galanter, and Conrod (2011) found a link between the social environment and substance use and addiction. The members of the public, who reported abuse in childhood, had a higher probability of abusing substances in the adulthood. Moreover, socio-economic factors are responsible for addiction (Pourmovahed & Yassini-Ardakani, 2013). Lack of employment, lack of familial supervision, poverty (low income), and marital problems have a proportionate correlation with substance abuse. Jedrzejczak (2005) shares the view that most drug addicts come from families where there was no supervision and the authority came from the mother. People who come from single-motherhood households are more likely to use and abuse drugs. The study also came to a conclusion that incomplete and pathological families play a role in contributing to drug addiction. Besides that, weaker ties in the families are also a predisposing factor to substance use and abuse of substances. Frank et al., (2011) notes that to most people drug addiction is maintained by repeated drug use as a result of socially learned cognitive facts, like beliefs, motives, and expectancies for substance utilisation. The mesolimbic dopamine system controls a person’s responses to natural rewards such as social interactions. As a result, it is a crucial determinant of motivation as well as incentive drive. When a person has the freedom to use and abuse drugs under no supervision are motivated to continue using the drug. In a similar perspective, the mesolimbic reward circuit informs the brain’s memory to pay attention to all features of the reward experience for it to be repeated in future. The memory of the drug experience is stored in the hippocampus along with the amygdala. Behavioural and personality factors Drug abuse is an etiologically complex syndrome also affected a diverse set of behavioural and personality risk factors reflecting the specific liability to substance use and abuse (Colder & Chassin, 2007). Temperamental people are more likely to use and abuse drugs (Wills & Dishion, 2012). For male children, the risk of developing an addiction is up to 8 times more in contrast to female children, especially in becoming an alcoholic (Frank et al., 2011). Young people who are often thrill-seeking often find pleasure in the utilisation of drugs. Factors like peer pressure and stress, and other behavioural and personality factors can significantly affect the occurrence of drug abuse in addition to the escalation to addiction in a person’s life. A study by Anton et al. (2006) reports that the treatment of alcohol and substance addiction can be done by increasing inhibitory (GABA) neurotransmission as well as reducing the stimulatory (glutamate) neurotransmission. As for alcohol addictions, the use of naltrexone obstructs the opioid receptors involved in the rewarding impacts of drinking and the craving for alcohol. Conclusion In summary, to better understand addiction in biological terms, the psychoactive drugs and drugs of abuse modify the normal balance and level of biochemical activity in the brain. The drugs of abuse induce activity in those areas of the brain that mediate the feelings of pleasure. The brain is responsible for one to have that feeling of pleasure after taking drugs. The drugs of abuse target the pleasure centre of the brain. The mesocorticolimbic pathway comprises of the mesocortical along with mesolimbic pathways and produce dopamine that is responsible for addiction. The dopamine is produced in the ventral tegmental area. The other brain structures that are responsible for that feeling of pleasure after taking drugs include the: anterior cingulated cortex, prefrontal cortex, dordal and ventral striatum, insular cortex, hypothalamus, hippocampus, and amygdale. This makes one to continue using the drug in order to have that good feeling. The long-term use results in addiction. A reduction in the dopamine levels results in depression. Substance use and abuse cause psychological, physical, social, and economic harm. In the same way, addiction is influenced by biological, social, psychological, and environmental factors. 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