Research methods- Clinical

Using the table For each method: Describe the method using example from clinical psychology Outline one strength (ensuring you use a study to support your point) Outline one weakness (ensuring you use a study to support your point)

Longitudinal Harrow et al. (2012) From 1975 to 1983, Harrow enrolled 200 people with a diagnosis of schizophrenia or a milder psychotic disorder into his NIMH-funded study, recruiting the patients from two Chicago hospitals. This study largely charted long-term outcomes in patients newly diagnosed, or recently diagnosed, with a psychotic disorder. All of the patients were treated conventionally in the hospital, and then Harrow followed them as their lives unfolded, periodically assessing how well they were doing.  Were they symptomatic? In recovery? Employed? Were they taking antipsychotic medications? Or other psychotic medications? He conducted such reviews at 2 years, 4.5 years, 7.5 years, 10 years, 15 years, and 20 years. At the end of 15 years, he had successfully followed 145 of the 200 patients enrolled into the study, and at the end of 20 years, he had outcomes data for 139 patients. For a long-term study, this is a very good retention rate. At the 10-year follow-up, 23% of the patients off antipsychotics were experiencing psychotic symptoms, versus 79% of those still on the drugs. At the 15-year followup, 28% of those off antipsychotics had psychotic symptoms, versus 64% of those on the medications. At year 20, those “who were not on antipsychotic medications were significantly less psychotic than those on antipsychotics.” Studying the same participant or participants over a long period of time to make comparisons in the data gathered over that time period Study in clinical that we can use? Harrow et al. (2012) 20-year longitudinal study and found that patients who did not take their medication had fewer psychotic episodes than those who did.  Using the details from the study – answer the questions in the table

Longitudinal Strength Shows changes in attitudes/behaviours over time and rich data ----> valid data Weakness Attrition rate (drop out rate) only 139 out of 200 from Harrow study. Ethical issues (privacy, intrusiveness, consent)

Cross- sectional Where data are collected at one moment in time, over a short period. ‘Snapshot’ Different participants but same moment in time Example in clinical psychology? Masellis (2003) Cross section of males and females with a diagnosis of OCD One moment in time One hospital Toronto Gathered data to find relationship between obsessions and QOL, compulsions and QOL and Depressive symptoms and QOL

Cross sectional Strengths Useful to gather data in a short period of time – efficient, less commitment needed and can lead to quicker results that can be applied to help change treatments (example Masellis) Weaknesses Descriptive research – not useful to see the course of the disorder or treatment

Cross- Cultural An anthropologist and several psychiatrists interviewed participants from the USA, India and Ghana, each sample comprising 20 persons who heard voices and met the inclusion criteria of schizophrenia, about their experience of voices. Results Participants in the USA were more likely to use diagnostic labels and to report violent commands than those in India and Ghana, who were more likely than the Americans to report rich relationships with their voices and less likely to describe the voices as the sign of a violated mind. They viewed the voices more positively, Conclusions These observations suggest that the voice-hearing experiences of people with serious psychotic disorder are shaped by local culture. If a patient is from a different culture to clinical cultural differences in what they conclude about their disorder may affect the clinician’s diagnosis (challenge to validity of diagnosis) Cultural differences in the new study help to explain why schizophrenia tends to be more severe and long-lasting in the United States than in India, Luhrmann proposes Studying behaviour or attitude by comparing data from different cultures Example: Luhrmann et al (2015) USA, India and Ghana page 21 of textbooks

Cross- Cultural Strengths Useful Should classification be universal? Is the outcome of the disorder the same for all or is the outcome shaped by beliefs and culture? Weakness Implications – socially sensitive research due to cultural differences (religion and interacting with voices vs. seeing the voice as abnormal and a symptom)

Schizophrenia as a complex trait: evidence from a meta-analysis of twin studies. Sullivan et al (2003) OBJECTIVE: To calculate meta-analytic estimates of heritability in liability and shared and individual-specific environmental effects from the pooled twin data. DATA SOURCES: We used a structured literature search to identify all published twin studies of schizophrenia, including MEDLINE, dissertation, and books-in-print searches. European countries, Japan, and the United States . 7out of 14 studies published before 1970. STUDY SELECTION: Of the 14 identified studies, 12 met the minimal inclusion criteria of systematic ascertainment. 2 excluded due to differences in methodology. DATA SYNTHESIS: We found evidence the estimate of heritability in liability to schizophrenia was 81%. Notably, there was consistent evidence across these studies for common or shared environmental influences on liability to schizophrenia-joint estimate, 11% (95% confidence interval, 3%-19%). CONCLUSIONS: Despite evidence of heterogeneity across studies, these meta-analytic results from 12 published twin studies of schizophrenia are consistent with a view of schizophrenia as a complex trait that results from genetic and environmental etiological influences. These results are broadly informative in that they provide no information about the specific identity of these etiological influences, but they do provide a component of a unifying empirical basis supporting the rationality of searches for underlying genetic and common environmental etiological factors. Meta-analysis Analysis also known as a review using results from other studies about the same issue. Studying results as a whole to analyse overall picture of the topic Sullivan et al. (2003) explanations of SZ (genetics) OR Hoffman et al. page 50 of textbook

Meta-anlaysis Strength Statistical analysis – combining data. Powerful statistical results in comparison to a single study Different cultures used – generalise to other cultures. (universality of the issue?) Larger sample due to using various studies – more generalisability Weakness Different research methods used – comparable data? Older and newer studies – different methods? Most studies in Sullivan’s work did not include several critical features (blinding and a standardised diagnostic approach) Now seen as imperative for empirical research Publication bias – what about studies that have not been published?