The Dopamine Theory and Treatment of Schizophrenia

In the field of psychiatric research there is perhaps no condition that has been as difficult to understand and treat as schizophrenia. For centuries it was considered absolute madness and treated as such. There were people who endured horrific treatments such as electroshock therapy and even insulin-induced coma therapy.

The fact that neither of these have any effect on the condition is not surprising. In modern times researchers are gaining some ground in terms of understanding schizophrenia. One of the theories that is quickly gaining some popularity is the dopamine theory. However, even with new theories there is still a great deal to learn about schizophrenia and how we can support the people who cope with this condition.  

Schizophrenia

Millions of people worldwide suffer with schizophrenia continue to cope with the stigma associated with psychiatric illness in many societies. As a result, some people do not seek treatment and end up self-medicating which only aggravates the condition. In addition to the symptoms listed above, people with schizophrenia can also experience a tendency to let go of reality, exhibit bizarre behavior and even experience the inability to express themselves emotionally. “Schizophrenia is considered the most chronic and disabling of the severe mental disorders. Even with treatment, most people diagnosed with schizophrenia suffer lifelong symptoms” (Beebe, 2003, p. 67). According to the DSM IV, schizophrenia is classified as a psychotic disorder and there are five distinct sub-types within the broader definition of the condition: catatonic, disorganized, paranoid, residual and undifferentiated.  

However, the DSM IV defines schizophrenia as being characterized as a person who experiences two more of these symptoms:  

 delusions,  hallucinations, disorganized speech (e.g., frequent derailment or incoherence), grossly disorganized or  catatonic behavior, negative symptoms, i.e., affective flattening, alogia (poverty of thinking evidenced either by  poverty of speech or by poverty of content of speech)., or  avolition  (absence of initiative or motivation to begin and maintain behavior in pursuit of a goal)

The Dopamine Theory

The dopamine theory attributes the symptoms of schizophrenia to disturbed and hyperactive dopaminergic   “Signal transduction” signal transduction. Schizophrenia has, in recent times, been treated with anti-psychotics which attempt to get the affects of the psychosis under control. “The neurotransmitter model focuses on chemical transmission in the prefrontal cortex, hippocampus, and temporal lobes of the brain, postulating that increased dopamine receptor activity in these areas results in hallucinations and delusions” (Beebe, 2003, p. 67).  

While clinicians have never associated physical pain with this condition, the constant mental distress no doubt has a short and long term physical effects. People with schizophrenia are in considerable mental distress and it may be that these dopamine levels are reacting with the stress that people experience and thus contributing to the development of the condition. In the past, this condition has often been mischaracterized as ‘split personality’. However, unlike multiple personality disorder, people with schizophrenia only have one personality which is split between mind and body. The person is often paralyzed by visions (hallucinations) and voices. These unseen (and really not present either) stimuli provide a constant barrage of visual and auditory messages that only the person with the condition can understand. In other words, there is a ‘division’ between psychological processes that are normally experienced as integrated (Bemak & Epp, 2002, p. 14).  

While many may ascribe to this theory, it is not the only theory that clinicians consider plausible. Some consider the condition to be a biochemical one where an imbalance exists in the brain. There are researchers who suggest that although additional theories have been and are being developed, the belief in schizophrenia as a biological/chemical problem is very popular. Even as these theories continue to be developed and re-developed, some suggest that our knowledge of this condition is still in its infancy.   “…the present state of knowledge regarding schizophrenia was like the ancient Indian legend of the blind men and the elephant, with different researchers both unwilling and unable to integrate the findings of rival disciplines” (Bemak & Epp, 2002, p. 15).  

While the DSM IV defines or characterizes schizophrenia as one condition, it also recognizes there are various sub-types of the condition. However, even in some clinical circles, this is considered insufficient to completely   understand this very complicated condition. There are those within the fields of psychology and psychiatry who believe that schizophrenia might not even be one condition with several sub-types at all, but several different conditions that exist on a continuum. The theory suggests that schizophrenia may in fact be several disorders which need to be clinically separated in order to fully understand this condition. Medical scientists pigeonhole and circumscribe schizophrenia as an autonomous disease when perhaps they should describe the continuum of psychotic experiences that vary in intensity as one surveys the diverse human responses to trauma (Bemak & Epp, 2002, p. 16).  

This theory is predicated on the evidence in clinical research that schizophrenia is associated with dopamine levels in the brain. However, that’s not all they’re associated with. “Dopamine appears to be associated with the mobilization, facilitation, and sustenance of goal- or incentive-related behavior and impairment in dopamine neurotransmission may mediate impulsivity and inattentiveness…” (Kafka, 1997, p. 349).   Clinicians also believe there is sufficient evidence to suggest that dopamine levels in the brain are also connected with our levels of creativity and the ability to seek novelty in our lives. Thus, if persons with schizophrenia are treated in such a way as to alter these levels then there might be a corresponding effect on the levels of creativity as well. One of the implications of this treatment is stated as follows:  

The fact that a healthy mental state and an abnormal one share the same neurochemical mechanism is not necessarily contradictory. The meaning of this relationship may be that in creative personalities, whose thinking is more fluid or looser than average, trauma may provoke the further loosening of thought associated with schizophrenia (Bemak & Epp, 2002, p. 16).

Additional research agrees that dopamine levels are definitely associated with the positive characteristics of appropriate levels of stimuli and motivation in the brain. “These findings suggest that normal dopamine transmission is necessary for the rewarding properties of stimuli to occur. Studies using dopamine agonists have also shown that stimulation of dopaminergic receptors is sufficient to reproduce these motivational effects” (Nader, Bechara & van der Kooy, 1997, p. 87).   Keltner, Hogan and Guy (2001) also agree that at least to some degree the use of drug therapy on dopamine receptors has had some success for persons coping with schizophrenia. These same researchers explain that since the theory first emerged there has been modification of both the theory and the drugs used in these treatments. Dopamine receptors have been divided into five typest–D1 to D5. Discovering dopamine receptor differences facilitates a better understanding of drug effects and aids in discovering receptor-specific agents” (Keltner, Hogan & Guy, 2001, p. 66). In research conducted in animal models of psychiatric disorders, Hitzeman (2000) states that “…psychosis is associated with increased levels of dopamine, drugs that block amphetamine-induced behavior would be effective as antipsychotics” (P. 151).  

There is in fact a great deal of research to suggest that the new antipsychotics are having a positive on people coping with schizophrenia. While the more severe symptoms of schizophrenia are the ones primarily associated with this condition, people with schizophrenia suffer with a broad range of difficulties aside from hallucinations, delusions, avolition and others. They also find it difficult to organize themselves on a practical level and coping on a daily basis becomes next to impossible without medication. People with schizophrenia find it hard to engage in sequential behavior, organize their thoughts and even engage in meaningful conversation which is why people with this condition become so completely debilitated. Persons with schizophrenia often have to cope with long periods of hospitalization and certainly require a broad range of supports in addition to medication to help them cope with this disabling condition.  

However, even with the advent of these new antipsychotics and the belief that schizophrenia is a chemical imbalance in the brain, not everyone is on board with the belief that this is the end of the story. Some researchers suggest that there may be a broad range of factors involved with the onset of a condition as complicated as schizophrenia. At least one theorist suggests that the dopamine theory is probably the most popular hypothesis that has a broad range of acceptance among clinicians around the world. The acceptance of this theory leads clinicians to use the antipsychotics, but some question whether this is actually changing anything but moods. “…the drug is correcting ‘a chemical imbalance’, or so runs the logic of this popular discourse. In fact, the drug may be producing any number of physiological or biochemical effects, none of which need have anything to do with correcting a chemical imbalance” (Arben, 1996, p. 68).

Arben suggests that one of the reasons the dopamine theory has become so widely accepted is because of the media it has received. World-wide media outlets got on board with disseminating articles in magazines and newspapers about the dopamine theory very quickly. Even though other theories are continually being developed none of them are gaining the same acceptance or the same kind of popularity in the media which makes it harder for them to be used by clinicians. According to Arben (1996) the dopamine hypothesis is based on “…highly tentative findings of small single studies as proven scientific fact and then failing to report or barely reporting that the study’s results have been retracted by its authors or that subsequent studies have failed to confirm the original findings” (p. 68).  

Arben also suggests that other theories which are primarily suggested by mental health professionals are often lagging behind due to poor funding and a hesitancy to make their research public due to concerns of appearing unscientific (1996). If these suggestions are true then it is still possible that even though the dopamine hypothesis has gained both international attention and acclaim that it is not the ‘true’ answer as to what causes schizophrenia. However, there is a strong push to keep defining schizophrenia as a biological disease which is caused by a chemical imbalance in the brain. Arben also suggests that it is in fact ‘easier’ to define schizophrenia as a chemical imbalance in the brain because that suits the current medical model of dealing with the health of the nation (1996). Once a condition is defined, the drugs are developed, the pharmaceuticals enter the picture, the drug is distributed and everyone is happy. However, the truth is not everyone is happy. Not all persons with schizophrenia react well to these drugs and some are not helped at all.  

Arben’s analysis raises interesting points. First, if schizophrenia is not entirely caused by a chemical imbalance which the dopamine theory suggests, then research must continue and keep looking for the complete answer. In addition, medical science is not treating the condition but only the symptoms. Therefore, people with schizophrenia are not truly being helped but simply medicated to the degree that they can cope with everyday life.  

Some would suggest that we have become a society that is far too reliant on medical diagnoses and drugs to alleviate every single problem. In a 1996 poll of over 1,000 Americans, at least half of the respondents stated they believe that people can avoid coming down with serious mental illness, even as severe as clinical or manic depress In that same poll which also discussed schizophrenia the results were absolutely shocking. “…many still believe schizophrenia is caused by drug abuse (63%), the environment in which a person is raised (53%), a nervous breakdown (51%), poor parenting (34%), weak willpower (22%), and/or laziness or idleness (13%)” (“What do people know”, 1997, p. 9). Therefore, irrespective of all the money spent on research and public education, there is still a great deal of misunderstanding of what schizophrenia is all about. Many people seem to hold a negative view of the medical profession and believe that too many of us have become overly reliant on drugs to cure every little thing that bothers us. This demonstrates a serious need for public education and outreach to help people understand the severity of schizophrenia.  

Even though many people want to believe that schizophrenia is not a real condition that requires medical treatment and some question the dopamine theory, there seems to be a great deal of research out there to support the evidence that schizophrenia is indeed connected to the neurotransmitters in the brain. If antipsychotics are having a good measure of success then how could they alleviating the more serious symptoms of the condition? The analogy can be made to other conditions as well. Anti-inflammatories are a widely used form of medication that address pain and inflammation in the body. However, if the source of the pain was not an inflammation then how could the drugs be effective to any degree? Since they are, it is reasonable to assume that anti-imflammatories are part of the solution for pain and inflammation in the body. Yet, it is also reasonable to assume that they are used in combination with other forms of treatment such as hot or cold compresses, exercise and physical therapy. The same should be thought of as true for schizophrenia. It does not seem as if the literature is suggesting in any way that antipsychotics are the whole answer for schizophrenia. Rather, the evidence suggests that they are part of a whole package. Additional aspects of treat that must be considered are supportive counseling, support groups, one on one coaching and family support. However, if the antipsychotics cam be part of an effective overall treatment plan then they seem to be a treatment that is definitely going in the right direction.

Whether one aggress with the dopamine theory or not, there appears to be a significant amount of research to prove that the antipsychotics being developed as a result of this theory have been developing rapidly since the 1950’s and these treatments continue to show tremendous promise. “They are equally effective at stemming the delusions and hallucinations and bizarre behavior and speech experienced by schizophrenics…” (Patlak, 1997, p. 25).   However, these drugs, as valuable as they are can also be extremely difficult to take. They are often associated with a broad range of side effects including muscle cramps, tremors, dry mouth, restlessness, drowsiness and others. The use of these antipsychotics are therefore often used in tandem with other drugs which try to keep the side effects under control (Patlak, 1997).  

Another cautionary tone about the drugs is the length of their use. The unfortunate reality is that many people with schizophrenia improve when they are on the medication. However, when they come off the drugs they often experience a relapse. It is therefore an unfortunate reality that many people with this condition will be on some form of medication their entire lives. Yet, the positive side of this is, these drugs are constantly being refined and able to control a broader range of the symptoms and not just the hallucinations and/or the delusions. Many people are experiencing relief from social withdrawl and the flattening ‘effect’ of schizophrenia.

The Biopsychosocial Theory

There is a wealth of literature to support the hypothesis that dopamine is indeed to some degree responsible for the onset of schizophrenia.   In addition to the dopamine factor however, specific stressors and genetic factors may also be important. “In the area of major mental illness, specifically schizophrenia, excluding biological or neurological factors from research is a liability for research and clinical efforts because schizophrenia is such a complex biopsychosocial phenomenon” (Farmer & Pandurangi, 1997, p. 109). The research conducted by Farmer and Pandurangi suggests that while dopamine may be a factor, there may be a tendency to inherit the specific levels of dopamine and how they function in a person’s brain. In other words, some people may be predisposed to chemical imbalances in the brain. The two researchers state very clearly though that the disease itself is not inherited but the vulnerability for the disease can be inherited.  

“…vulnerability, in combination with relevant stressors, leads to the development of symptoms of schizophrenia. This perspective integrates biological characteristics with psychological and social aspects of human behavior, providing a biopsychosocial understanding of the variables that lead to a schizophrenic illness” (Farmer & Pandurangi, 1997, p. 109).

In this particular theory, schizophrenia is not seen as one condition but a condition with many subtypes that exists on a continuum. Thus, the researchers believe there is sufficient evidence to suggest that certain brain ‘types’ may be associates with the different sub-types of schizophrenia   The research that moves in this direction believes that different medications must be developed for the sub-types and not for ‘schizophrenia in general. People who have the various sub-types will react to medications differently and have different tendencies towards relapse. The research ascribes to the belief that schizophrenia is indeed connected to the brain but there are several parts of the brain involved and no one area can be thought of as responsible for causing the condition. “Schizophrenia can be associated with certain brain characteristics. Brain areas implicated in this illness are the frontal lobe, temporal lobes, limbic system, and basal ganglia. However, there is probably not one single area of the brain associated with the illness…”(Farmer & Pandurangi, 1997, p. 110).

The hypothesis that different parts of the brain are responsible for the various symptoms of schizophrenia might not be far-fetched. Research has stipulated for some time that different parts of the brain are responsible for different areas of our behavior, thoughts, etc. However, this has important consequences for the research on schizophrenia. In the research conducted by Farmer and Pandurangi, some very interesting data was revealed. They state the following:

However, the results of this study demonstrate that gender and race can be related to the course of illness and may provide additional data about the heterogeneity of schizophrenia. That women and African Americans in the study group experienced a more benign form of schizophrenia underscores the complexity of interactions between nature and nurture. Being a member of an oppressed group (for example, women and African Americans) might affect the experience of having a schizophrenic illness if society’s performance expectations are lowered or altered because of membership in that group.  

(1997, p. 116).  

The researchers admit that the sample size for this study was small (42) and the results of this study should be read with caution. Several other limitations in the study are mentioned in the write up but the authors still believe there is some validity to this study. Irrespective of the limitations the authors continue to suggest that schizophrenia is not a homogenous disorder but a series of disorders that can only be understood and treated with a biopsychosocial approach.  

One of the most interesting articles reviewed for this research vividly describes the hallucinations experienced by people with schizophrenia. The visions are terrifying. At the same time however they illuminate the world as it is experienced by people with schizophrenia. While medical researchers do endeavor to try and unlock the secrets of psychiatric conditions there are the lived experiences of the people who must cope with the horrifying reality of schizophrenia on a daily basis. In the end, these are the only people who can say whether or not any ‘treatment is working’. The antipsychotic drugs, the psychotherapeutic approaches and all the theories mean nothing if, in the end, they cannot bring relief to the millions of people who suffer with schizophrenia. The word suffer is appropriate here because the people with this condition do indeed suffer.  

Additional Research on Schizophrenia

Hallucinations can be so oppressive and frightening that people with schizophrenia no longer even know the world around them. They live in a surreal state akin to a Dali painting. One person described his visions in the following way: “The voices either ramble in alien tongues or scream orders to carry out violent acts. They also persecute me by way of unwavering commentary and ridicule to deceive, derange, and force me into a world of crippling paranoia”(Patlak, 1997, p. 23).   According to this one individual the new antipsychotics do work. The drugs provide relief from what would otherwise be a living hell. However, while the drugs work additional research is demonstrating that the dopamine theory is not necessarily the whole story with why they work. At least one piece of research suggests that viral infections during pregnancy can affect the development of the fetal brain. As a result of this faulty brain development, some individuals go on to develop schizophrenia.  

The fact that these drugs do work is certainly a positive sign. However, the reality for a high percentage of people with schizophrenia is that they will have to be on these drugs for the rest of their life. Otherwise, they risk relapse. Yet, even though the drugs provide a measure of relief, it is vital to remember that this is only partial relief. “Studies suggest the addition of anti-anxiety medications such as lorazepam (Ativen) or alprazolam (Xanax) helps about half of schizophrenics, according to James Thompson, M.D., of the University of Maryland in Baltimore” (Patlak, 1997, p. 27).   In addition to the antipsychotics and anti-anxiety medications, some people with schizophrenia may be on medications for other health problems as well which makes them entirely dependent on drugs. One of the ways of coping with this reality and the difficulties in dealing with schizophrenia is psychotherapy. The tools of psychotherapy have long been touted as being helpful with a broad range of psychiatric conditions including schizophrenia. “…recent studies indicate that supportive reality-oriented therapy aimed at developing practical interpersonal skills is generally of more benefit to schizophrenics than more probing psychoanalytic or insight-oriented psychotherapy” (Patlak, 1997, p. 27).  

CONCLUSION

The literature reviewed for this paper is definitely clear that schizophrenia is the most complicated of all the psychiatric conditions to understand and treat. The research on the dopamine theory states that the dopamine levels in the brain are one of the central factors in the development of schizophrenia. However, as this paper has noted, that body of research is still unclear as to why some people have a problem with dopamine levels. At least one piece of research suggests that schizophrenia may be associated with specific personality types.

Elevated dopamine activity appears in personalities that are intolerant of structure and monotony, whereas low dopamine activity appears in those personalities manifesting orderliness and inflexibility. To be clear, it seems that the levels of dopamine reveal an unexpected parallel: Dopamine activity correlates with both schizophrenia and creativity (Beemak & Epp, 2000, p. 16).

In this theory, people who have high levels of creativity, high levels of dopamine, and experience a sequence of traumatic events and/or stressors may be predisposed to developing schizophrenia.  

Some of the research suggests there could be genetic factors at work. Other research suggests that in addition to genetic factors, there are psychosocial factors that must be considered such as stress or a traumatic event which could be part of the reason why some people become ‘schizophrenic’. Still other research suggests that it is all of these factors together which create the predisposition towards schizophrenia.  

Many questions remain unanswered. The one fact that we do know is that the development of newer antipsychotics have been able to provide people who suffer with schizophrenia at least some measure of relief and the ability to live their lives. However, these drugs can often cause a broad range of side effects which can also be disabling to the individual. In addition to the drugs, people with this condition are definitely in need of strong supports including professional counseling and other community support services. Most people with schizophrenia will live with the condition their entire lives. Many will require several periods of hospitalization. Some will react well to the drugs but some do not. There are also many people who do well on the drugs and then come off in the belief that the condition has been cured, only to find they relapse.  

At least one research article suggests that even though there may indeed be a connection between elevated levels of dopamine and schizophrenia, there are literally hundreds of neurotransmitters in the brain. This fact means that the dopamine theory may be an oversimplification of what is likely to be a far more complex connection than research has yet to uncover. However, even though we don’t yet fully understand the connection (or all the connections) between dopamine levels and schizophrenia, the theory is an excellent starting point for further research which is definitely promising. The current data suggests that a high percentage, anywhere from 30% to 60% of people who take these antipsychotics do experience a measure of relief (Bemak & Epp, 2002).  

The unfortunate truth is there is no ‘cure’ for schizophrenia. There is only the constant need to keep researching and understanding this complex condition in greater depth and provide the people who suffer with it a ‘healthy and complete life’.  

References

Arben, P. D. (1996). Are Mental Illnesses Biological Diseases? Some Public Policy Implications. Health and Social Work, 21(1), 66-71.  

Beebe, L. H. (2003). Theory-Based Research in Schizophrenia. Perspectives in Psychiatric Care, 39(2), 67-78.

Bemak, F., & Epp, L. (2002). Transcending the Mind-Body Dichotomy: Schizophrenia Reexamined. Journal of Humanistic Counseling, Education and Development, 41(1), 14-30.

Dworkin. R. W. (2001). The Medicalization of Unhappiness. Public Interest, 85-95

Farmer, R. L., & Pandurangi, A. K. (1997). Diversity in Schizophrenia: Toward a Richer Biopsychososocial Understanding for Social Work Practice. Health and Social Work, 22(2), 109-120.