Cannabis (marijuana, ganja, weed, hash, skunk etc) from the plant species Cannabis sativa . Types ; Hash (brown lump formed from the resin of the plant), Weed (traditional cannabis, made from the dried leaves of the plant), Sinsemella (a bud grown in place of the male plant which has no seeds, known as “skunk”, the strongest type and most common. 81% sold on the streets). Ingestion takes many forms! Class B drug (as of Jan 2009) strengthening laws to crack down on illegal use. Until this date it remains a class C drug, with lower penalties for possession, trade and use. Chemicals along with dopamine and the main active chemical (THC) tetrahydrocannabinol in cannabis, causes hallucination, reduced co-ordination, risk of lung disease, cancer and schizophrenia, increased heart rate and pressure, reduced sperm count in males, suppressed ovulation in women, reduced learning and concentration and tiredness. ( www.homeoffice.gov.uk ) , ( www.talktofrank.com )
Schizophrenia a chronic mental health condition that causes a range of psychological symptoms including hallucinations and delusions. 1 in 100 people will experience at least one acute period of schizophrenia, men and women are equally affected by the condition. Symptoms include, lack of co ordination, becoming confused, delusional, hallucinogenic, lack of emotion, apathy, withdrawal and many other symptoms. It is widely known that schizophrenia has many causes, it could be down to a predisposed gene being triggered by environmental effects such as stress etc, cannabis increasing levels of dopamine causing the psychosis (2x more likely compared to non drug users) or lastly an early development in the brain. ( www.nhsdirect.nhs.uk )
Hypothesis: There is a link between cannabis use and developing schizophrenia. Null Hypothesis: There is no link between cannabis use and developing schizophrenia.
The Nuremberg code is a set of internationally accepted rules for conducting human medical experiments. This has been in place since the 1940’s. Alan Milstein, a nationally known bioethics litigator raised the issue in a quote, whereby he declared “A successful result will never make an unethical result ethical”. There are current principles, written by The National Commission for the Protection of Human Subjects of Biomedical and Behavioural Research. Such principles should be adhered to in order to ensure legality of the experimental research.
Safety - a risk/benefit ratio should be carried out prior to commencing the research. Consent - Informed consent must be obtained from each research participant, and is generally done in writing and at this point there is a chance for the participant to ask any questions Voluntariness - i.e; the participant must be free from any influence. Competence - i.e their mental capacity must be sound, if not there should be a designated surrogate available to provide this consent in place of them if it is in the participants best interests to participate. Any adverse effects that may occur must be considered by the investigator; this includes deciding who will provide care for a participant, and who will pay for it should there be any injuries. Confidentiality and privacy - these issues must be explained before starting the research.
<ul><li>1. Create a questionnaire designed to find out: </li></ul><ul><li>The fraction of a sample population that are consuming Cannabis (including frequency and quantity). </li></ul><ul><li>The fraction of that sample population that to develop Schizophrenia. </li></ul><ul><li>The reason(s) for Schizophrenics developing the disease. </li></ul><ul><li>2. Distribute the questionnaire to as many youths (aged 16-20, a control group of non-drug users as well as drug users) as possible, by email and letters to universities, youth centres and drug-rehabilitation centres. Participation is voluntary and subjects can opt-out at any time. Ideally a sample size of a minimum of 100 subjects. </li></ul><ul><li>3. All data from completed returned questionnaires can then be tabulated in an excel spreadsheet. </li></ul><ul><li>4. Continue to distribute the questionnaire to the same individuals annually, using the same questionnaire. Annual data will be applied to a new sheet in excel. Continue the study until subjects opt-out, in order to collect as much data as possible. </li></ul><ul><li>5. Perform statistical test to test hypothesis. </li></ul>
<ul><li>Questionnaire: </li></ul><ul><li>Name (can remain anonymous but please leave a unique username) _____________ Age _____ </li></ul><ul><li>Do you currently consume Cannabis? Yes No </li></ul><ul><li>How frequently do/have you ingested) Cannabis? Daily Weekly Monthly Annually Twice Once Never </li></ul><ul><li>In what form have you ingested Cannabis? _______________________ </li></ul><ul><li>Approximately how long has this been (or was this) a habit? __years __months </li></ul><ul><li>Approximately what quantity is ingested on each occasion? ___grams </li></ul><ul><li>Have you ever been diagnosed with Schizophrenia? Yes (type __________) No </li></ul><ul><li>If so, when (date, month/year)? </li></ul><ul><li>Did you experience any hallucinogenic effects when ingesting Cannabis? Yes No </li></ul><ul><li>Has a blood relative been diagnosed with Schizophrenia? Yes (type __________) No </li></ul><ul><li>Has a non-blood relative been diagnosed with Schizophrenia? Yes (type ___________) No </li></ul><ul><li>Do you take any other drugs/medications (if so please specify)? __________________ </li></ul><ul><li>Additional comments: _____________________________________________________ </li></ul><ul><li>_________________________________________________________________________ </li></ul><ul><li>_________________________________________________________________________ </li></ul>
Two way ANOVA analysis, looks at the relationship of the observed variance between the two samples, then partitioned into separate components due to the difference in the two variables. In this case the analysis variance comparison will be used to make a comparison between the frequency and consumption of cannabis among users, compared to people who don’t consume cannabis, to see of there is a relationship between these factors and developing schizophrenia. This test will be used to derive and analyse graphs from the questionnaire, to see if increased years of cannabis consumption, increase developing schizophrenia later in life. However a problem associated with this is also that the nature of the study may require direct and independent results from some of the subjects, collected in ‘open ended’ questions. These question would be much harder to analyse, as would have many, independent variables as well as being subjective to the subject used.
A paired t -test is an statistical hypothesis test designed to compare the average difference between two groups, to determine whether the relationship is significant, as it does explain the relationship, or is down to random chance In reference to the use of this t- test for comparing the results from two samples of data, we will look at the frequency and quantity of taking cannabis against not taking cannabis over the years, against whether there has been a rise in schizophrenia cases reported. This should provide conclusions whether there is a significant relationship between the variables. We would use a paired t-test because will be using a longitudinal study and using the results from the same population. A two tailed test would be conducted as there is an analysis between two sets of results Determining a p-value below the chosen statistical significance (0.05 and 95% confidence level) would indicate that there is a direct relationship between cannabis users and developing schizophrenia.
Frequency Cannabis consumed Number of subjects Average quantity consumed by subjects Total quantity consumed Number developing Schizophrenia Type of Schizophrenia Never Once Twice Annually Monthly Weekly Daily
Longitudinal observational study advantages; Greater depth of knowledge can be obtained as a relationship established. Doesn’t rely on memory recall from many years previously. Ethical and don’t have to interfere with lifestyle. Quick questionnaire sent online makes it easy to involve many subjects. Cost efficient. Subjects may feel confident about discussing their use of illegal substances through questionnaire safe in the knowledge they can remain anonymous and we don’t know them. The questionnaire may show links between variables other than those hypothesised to have an association. Disadvantages; Over a long period of time there can be a large number of subjects that drop out. Subjects can lie in questionnaire. Relies on subjects suffering from Schizophrenic symptoms visiting a doctor (men are notorious for not going). Only certain types of people will answer questionnaires. May not be good representation of population.
Home Office, 2008. Cannabis classification. [Online] available at http://www.homeoffice.gov.uk/drugs/drugs-law/cannabis-reclassification/ [Accessed on 21 st October 2008] Frank, 2008. Cannabis. [Online] available at http://www.talktofrank.com/drugs.aspx?id=172#appearance [Accessed on 22 nd October 2008] NHS, 2008. Schizophrenia. [Online] available at http://www.nhsdirect.nhs.uk/articles/article.aspx?articleId=329§ionId=10/ [Accessed on 22 nd October 2008] Cottlesman,M.M, Sandler, A.L, (2004). Guidelines for the conduct of research involving human subjects. Department of health and human services.