Abstract
The purpose of this paper is to exercise knowledge gained from studies in research methods, focusing on quantitative techniques. It answers questions on a statistical analysis of data and uses statistics to answer the research questions or test the hypothesis. It uses three simple case studies to answer these questions. In addition, the paper develops a comprehensive critique of a journal article that reports a quantitative study carried out in Munich and published in 2005.
Summary
The researcher’s aim was to determine whether there is a relationship between using cannabis and psychosis. It focused on people with a predisposition for the condition and those who took the drug during their teenage. Though not stated in a conventional manner, the research hypothesis argued that the use of cannabis in youths increases the risk of developing psychotic symptoms but the effect is highest in the individuals with evidence of predisposition to the condition (Moore, Zammit, Lingford-Hughes, Barnes, et al., 2007). This means that the alternative hypothesis argued that though there is evidence that cannabis use increases the risk of developing psychotic symptoms among the youths, there is no correlation between the use of substances during adolescence and a stronger risk of developing psychotic symptoms. Thus, statistical analysis with human samples was the chosen method for testing this hypothesis.
Methods
The study was quantitative research because it focused on a statistical approach to answering the study question (testing the null hypothesis). The researchers used interviews and a four-year follow-up to assess the use of the substance, symptoms and predisposition to the disease.
The study sample consisted of 2237 individuals aged between 14 and 24 years with and without the predisposition to the condition under test. The main aspect that was measured was “the presence of psychotic symptoms in the four-year period”. This measure was determined as a function of the use of the substance. It was also a factor of predisposition. The samples were obtained from a random sampling of young people in 29 counties in Munich. In addition, the baseline population consisted of the people born between June 1, 1970, and May 31, 1981. In addition, the criterion was to include the individuals who were officially registered residents of the counties. The researchers interviewed some 3021 individuals at the baseline. The interview process was done in a face-to-face manner, with each person visiting his or her home.
Data analysis involved the use of SPSS, ANOVA and other computer-based techniques. It involved analysis of statistical aspects to determine the correlation between the two variables under test.
Results
The researchers followed some 2437 participants in the study, with the number of males being 1251 or 51.3% of the total. The rest were female participants, which indicates that the gender bias was reduced to the minimum possible. It is also worth noting that the study lasted four years and found that about 17.4% of the participants developed at least one form of psychotic symptom. In addition, 7.1% had experienced at least 2 types of symptoms in their past. Moreover, the study found that about 13.1% of the individuals admitted to having used cannabis at least five times during their adolescent age (Henquet, Krabbendam, Spauwen, Kaplan, et al., 2005).
For the whole group of samples, the researchers used an odds ratio of 1.42, 95% CI 0.94 to 2.15. Using 1000 imputation sequences, the researchers found that the estimated additive interaction between the two variables at the baseline retained a high degree of significance at 19.5% difference of risk, a CI of 95% and 0.039 as the p-value.
Discussion
The study found that there was a significant correlation between the use of cannabis during adolescence and the development of psychotic symptoms. This is an important study because it addresses a current problem. In addition, it uses a quantitative approach to the problem, using human samples. The efficacy of the results is relatively high because the parameters and confounding factors were limited. Moreover, the study was carried out over a long time (4 years) which makes it reliable.
However, it has some weaknesses. For instance, interviews can provide misleading data because individuals tend to cheat when asked sensitive questions. Moreover, other limitations include the loss of samples during follow-up since the period is quite long.
The study can be improved in the future by incorporating samples from additional areas beyond Munich to ensure that the sample is representative of the whole population in the country.
References
Henquet, C., Krabbendam, L., Spauwen, J., Kaplan, C., et al. (2005). A prospective cohort study of cannabis use, predisposition for psychosis, and psychotic symptoms in young people. Bmj, 330(7481), 11.
Kothari, C. R. (2011). Research Methodology: Methods and Techniques. Washington, DC: New Age Publications
Moore, T. H., Zammit, S., Lingford-Hughes, A., Barnes, T. R., et al. (2007). Cannabis use and risk of psychotic or affective mental health outcomes: a systematic review. The Lancet, 370(9584), 319-328.
Munro, B. H. (2013). Statistical methods for health care research. New York: Lippincott Williams & Wilkins.