Question 110 marks
Question
The key study by Grant et al. (2008) treated gambling disorder in one of two double-blind placebo-controlled trials, in a university and treatment centres. (a) (i) Identify the drug used in each trial. [2] (ii) State the duration of each trial. [2] (b) Suggest why placebo-controlled trials were used in this study. [2] (c) Explain one strength and one weakness of using multiple locations within this study. [4]
Mark scheme
1 The key study by Grant et al. (2008) treated gambling disorder in one of two double-blind placebo-controlled trials, in a university and treatment centres. 1(a)(i) Identify the drug used in each trial. 2 Syllabus: 1.3.3 Key study on treating gambling disorder with drugs and placebo: Grant et al. (2008). Marks: Award 1 mark for each correct answer. Definitive answers: • Nalmefene (1 mark) • Naltrexone (1 mark) NB: trial does not need to be specified (e.g. trial 1 = nalmefene) NB: 0 marks for opioid antagonists. 1(a)(ii) State the duration of each trial. 2 Marks: Award 1 mark for each correct answer. Definitive answers: • 16 weeks (1 mark) • 18 weeks (1 mark) NB: trial does not need to be specified (e.g. trial 1 = 16 weeks) 1(b) Suggest why placebo-controlled trials were used in this study. 2 Marks: Award 2 marks for an appropriate suggestion stated and applied to study with detail / elaboration / example. Award 1 mark for an appropriate suggestion identified but not applied. Answers may include (other appropriate responses to be credited): • to find out whether a drug treatment works better than a substance that does not have an active drug in it (1 mark) • to act as a control group or baseline to compare ‘with drug’ and ‘without drug’ conditions (1 mark) • to provide a baseline for a comparison between drug and non -drug conditions (1 mark) • without it, it might lead to false conclusions about the effect of the drug (1 mark) • without a placebo group, participants would know that they are receiving an active drug and this alone might result in a change in behaviour (1 mark) • related to study: inclusion of nalmefene/naltrexone; treatment of gambling disorder (+1 mark). NB: answer must refer to placebo for 2 marks. 1(c) Explain one strength and one weakness of using multiple locations 4 within this study. Marks: up to 2 marks for each strength and up to 2 marks for each weakness: Award 2 marks for an appropriate strength/weakness stated and applied as required by the question with detail/elaboration/example. Award 1 mark for an appropriate strength/weakness stated but not applied. Answers may include (other appropriate responses to be credited): Strengths: • participants might be different, perhaps making the study more representative/generalisable (1 mark) such as those living close to a university compared to those living near a treatment centre (2 marks) • a different location may provide a different outcome (1 mark) a study conducted in a laboratory (University of Minnesota) compared to a real- life setting (out-patient psychiatric treatment centres) (2 marks) Weaknesses: • participants in one location might have different characteristics from participants in a different location (1 mark) in this study participants were either at a University (attended there/students) rather than those at treatment centres (non-students) (2 marks) • different locations might attract different types of personalities which might affect behaviour/results (1 mark) people perhaps might participate at a university rather than a treatment centre/might participate because it is a treatment centre (2 marks)