The Issue of Co-Morbidity and Dual Diagnosis - Essay Example

This paper looks into the issue of co morbidity and dual diagnosis. Substance abuse mental disorders are often linked together. Alcohol is linked with depression as cannabis is linked with psychosis and schizophrenia. This paper looks into and reviews various studies conducted to elucidate the relationship between cannabis and psychosis. Does cannabis usage precede psychosis and related disorders Does the its usage cause psychosis /schizophrenia in otherwise normal healthy people Or does it cause psychosis in people who already are vulnerable to the disease i.e. already have other risk factors for the disease. We look into 3 studies each of which provide evidence of one hypothesis or another. In the end we conclude that cannabis aggravates already susceptible people's condition who are young users and predominantly male and pushes them into a symptomatic stage of psychosis, rather than causing psychosis in an otherwise normal individual. Introduction It has been demonstrated by many a studies that substance abuse is more prevalent in patients with psychotic disorders than in the general population. What is of debate is whether substance abuse precedes psychotic disorders like schizophrenia and is a risk factor for the disease or whether it is just the fact that people with the disorders tend to misuse the drugs. Alcohol and cannabis are the most commonly abused drugs in the general population as well as in people with mental disabilities. Since the middle of the 20th century, the use of mental state altering drugs has increased. Cannabis use has been on the rise and although many attempts have been made to associate or disassociate it from disorders linked with it, researchers are still debating the full impact cannabis use might have on the public. It is imperative that agreement be achieved on the effects of cannabis so that policies and restriction on community use and definitive treatments can be provided to the affected people. Cannabis and schizophrenia: model projections of the impact of the rise in cannabis use on historical and future trends in schizophrenia in England and Wales The exact relation between cannabis use and the harm it may cause has been an area of debate for a long time. Numerous attempts have been made to point the exact nature of the relationship cannabis use has with psychotic disorders and schizophrenia. The recent cause of concern is the fact that multiple studies are pointing the finger at the hypothesis that cannabis use leads to schizophrenia. Hickman M et al (2007) in their study have tried to estimate long term patterns of cannabis use in the general population and attempted to and estimate and observe if the schizophrenia rates follow the same pattern. This pattern, if could to be present, they believe could demonstrate that cannabis usage has a direct relationship with schizophrenia as has been proposed by numerous old studies. "Trends in cannabis use were estimated from a national survey, and the incidence of schizophrenia was derived from surveys in three cities. A difference equation cohort model was fitted against estimates of schizophrenia incidence, trends in cannabis exposure and assumptions on association between cannabis and schizophrenia. The model projects trends in schizophrenia incidence, prevalence and attributable fraction of cannabis induced schizophrenia" (Hickman M et al, 2007). Hickman M et al has shown that over the past few decades cannabis use has gradually, but steadily increased in the young age groups of the society. He argues that if there was a casual relationship between cannabis use and schizophrenia prevalence, then the incidence and prevalence of disease should also show an upwards trend in the younger generation (assuming that all other factors remain constant). But recent studies of epidemiology according to Hickman (2007) suggest that schizophrenia's incidence and prevalence is in a downward trend. Their projections for the future also show a downward or a trend. This pattern contradicts the theory of casual association between cannabis and the disease. However Hickman does point out that the pattern of the disease is changing more towards the younger male generation age groups and this pattern is also seen in cannabis users. A limitation to Hickman's model for projection of schizophrenia estimates is that they did not take into account other risk factors and/or factors which may protect one from the disease. Hickman accepts that ignoring the other factors may have lead to the altering of projected schizophrenia incidence and prevalence rates. "It is conceivable that a change in other factors could have masked or diminished the recent and future projected increases in schizophrenia occurrence due to cannabis. This could explain further why no change in schizophrenia trends has been observed" (Hickman M et al, 2007). Another limitation to the study is that cannabis usage trends of the past were estimated from a single survey and this may have suffered from recall bias. Lastly, the exposure levels of cannabis use were not estimated, that is to say that the frequency and the quantity. Therefore Hickman's cannabis use estimates are crude to say the least. To conclude, Hickman's study proposes that a relationship between cannabis use and schizophrenia does exist as shown by the increase in schizophrenia in young adult males which is comparable to increase in young adult male cannabis users, but the extent and the depth of this relationship can only be gauged if schizophrenia's incidence and prevalence has a sharp upward trend by in the next few years. Patterns, predictors and impact of substance use in early psychosis: a longitudinal study Addington J et al in (2006) conducted a study to estimate the prevalence of Alcohol or drug abuse in patients who have had an episode of psychosis and to see the impact of the abuse after 3 years. Patients who had an initial episode of psychosis and had entered into a treatment program were the sample for the study. Multiple scales were used for the assessment ad evaluation of the severity of the disease and information about the substance abuse was collected. Patients were followed up every year for 3 consecutive years and updates about the substance abuse and estimation of the level of psychosis was done. According to Addington J's study, alcohol and cannabis were the most commonly abused substances. Their study found out that more than half of the patients who had an episode of psychosis also had a co morbidity of substance use disorder (SUD). One third of the patients were cannabis users. This study found out that cannabis misuse was more prevalent in patients who were young male adults who started the misuse of cannabis early on in their life. Addington J's study also found out that cannabis users demonstrated consistently higher positive symptoms of the disease throughout the follow-up. Addington J suggests that this pattern of cannabis demonstrates that the drug acts triggers the 'At risk' segment of the society into the state of psychosis. That is to say that it cannabis use is more harmful to the population who are at risk for the disease. Addington J further demonstrated that cannabis use after the initial episode of psychosis leads to aggravation of the psychotic symptoms and therefore leads to a negative outcome with respect to the disability. Unlike Hickman's study, Addington J in his study used a series of confirmatory test and follow-up rather than estimates and predictions and has demonstrated that cannabis use does influence the state of the disease as well as its outcome with respect to symptoms. Limitations in Addington J's study amount to the absence of a comparison group or control. This could have been a group with the psychotic disease but without the SUD, or people who are drug users but did not have the psychotic disease. As with Hickman's study, Addington J also did not take into account the quantity of the drugs that the patients were consuming. Taking this into account may shed some light on to the dose- response relationship between cannabis and psychotic disorders, which has been proposed by some studies. In conclusion, Addington demonstrated that cannabis use causes the aggravation of and increase in frequency of the positive symptoms of the psychotic disorders including schizophrenia in patients with the disease. He has suggested that its use is a negative prognostic factor. He also proposes the idea that rather than causing psychotic disorders out right, cannabis use may cause the psychosis only in people susceptible to or at risk for the disease. Cannabis use and psychotic disorders-an update Hall W et al in 2005 discussed three hypotheses which have been up for debate in the recent past. "These are that: (1) cannabis use causes a psychotic disorder that would not have occurred in the absence of cannabis use; (2) that cannabis use may precipitate schizophrenia or exacerbate its symptoms; and (3) that cannabis use may exacerbate the symptoms of psychosis" (Hall W et al, 2005). Hall uses data and results of multiple studies, longitudinal as well as cohort studies and tries to weigh the evidence for and against each of the hypothesis proposed. Using a case series of 200 patients, Hall W finds support for the proposal that heavy cannabis use leads to a sort of toxic psychosis. According to Hall W, the case series showed that the more potent the cannabis consumed, the less time it took for the psychotic symptoms to develop. Even though the results of the case series have been replicated else where, Hall W notes that clinical picture of the symptoms has varied from study to study. In support of the hypothesis that psychosis is associated with cannabis use, Hall W presents a study by Tien and Anthony, which demonstrated that regular use of cannabis in people doubled the risk for psychotic symptoms. Other studies including one done in New Zealand also showed that more than 10 % of cannabis users reported hallucinations and other experiences, which is far more than the number reported in the general community. To support the second hypothesis proposed by Hall W, he refers to case control studies which observed that cannabis use was higher amongst schizophrenia patients as compared to the general population. He also notes that multiple community based surveys have shown that schizophrenic patients are increasingly linked with increased cannabis usage. To support the link of cannabis use to schizophrenia Hall W produces evidence from a Swedish conscript study. The results of this study showed not only were the cannabis users more at risk for schizophrenia but also that male users and those who start using the drug at a young age are more prone to develop the symptoms. The Swedish study, as well as a follow-up study provides evidence of a dose response relationship between cannabis and schizophrenia. A Longitudinal study is presented by Hall as evidence that schizophrenia is precipitated by the use of cannabis. This study by Van Os et al demonstrated that people who reported the occurrence of psychotic symptoms were more prone to develop schizophrenia when compared with the who's who did not use cannabis. In this study cannabis use accounted for more than eighty percent higher risk for developing a disorder related to psychosis. To support the relationship between cannabis use early in life and its effects on mental health, Hall provides evidence from the Dunham study which studied multiple drug abuses and the occurrence of varied mental disorders. The results of this study showed "There were no relationship between other drug use and psychotic disorders and no relationship between cannabis use and depression. There was also an interaction between psychosis risk and age of onset of cannabis use, with earlier onset being more strongly related to psychosis. There was also the suggestion of an interaction between cannabis use and vulnerability, with a higher risk of psychosis among cannabis users who reported psychotic symptoms at age." (Hall W et al, 2005) Hall W uses the Christchurch study to reinforce evidence of early use cannabis to psychotic symptoms later in life. Hall is of the view that more evidence is present to support the theory that cannabis exacerbates schizophrenia rather than it being the cause of a different cannabis psychosis. Summary Cannabis use has been associated with schizophrenia, cannabis psychosis and with psychotic symptoms. The study by Hickman attempted to predict the patterns of schizophrenia over a few decades and compared it with the trends of incidence and prevalence of schizophrenia. He concluded that although a clear pattern may emerge in the next few years but as of present there increased cannabis use has not caused a similar increase in the incidence and prevalence of schizophrenia. His study used a strict definition of schizophrenia and therefore might be susceptible to under reporting and non reliable results. Addington used a more through method, clinical assessment methods of diagnosis and came to a conclusion that there definitely was an association between Cannabis use and psychotic symptoms. He proposes that the young, males, who patients who are vulnerable to the psychotic disorders are more prone to get affected by psychotic symptoms after cannabis use. Finally Hall echoes Addington's hypotheses and further proposes that cannabis use at early age not only can lead to psychotic symptoms but can also push the vulnerable people into a schizophrenia state. Therefore we can conclude without question that a link between cannabis use and psychosis does exist. More evidence is present to support the theory that it aggravates the condition in susceptible people rather than causing a new disorder, the so called Cannabis psychosis. Therefore efforts should be focused on informing and treatment of people at risk for such conditions. References 1. Addington J, Addington D (2007). Patterns, predictors and impact of substance use in early psychosis: a longitudinal study Acta Psychiatyr Scand.115: 304-309 2. Hall W, Degenhardt L,TeessonM, (2005). Cannabis use and psychotic disorders: an update. Drug and Alcohol Review 23; 433 - 443 3. Hickman M, Vickerman P, Macleod J, Kirkbride J & Jones PB,. (2007) Cannabis and schizophrenia: model projections of the impact of the rise in cannabis use on historical andfuture trends in schizophrenia in England andWales. Addiction, 102, 597-606 Read More