Research looking at treatment

The Collaboration is an international, independent and not-for-profit organization which examines research trials to find what the best practice should be in medicine.  A central administration team supports the Schizophrenia Review Group in developing systematic reviews on interventions for schizophrenia and psychosis. There are review groups in all health and disease conditions and they are spread across the world, generally based at universities and teaching hospitals.

 I will be writing plain language summaries of these reviews and will also write about some of my thoughts and feelings in a blog, around what I have been reading and writing.

What is a systematic review and how is it written?

A systematic review summarises the results of available carefully designed healthcare studies (randomised controlled trials – RCTs) and provides a high level of evidence on the effectiveness of healthcare interventions.

To write a review, a small group of people look critically at RCTs that have appeared in the medical or health literature on a particular topic (‘reviewing the literature’).  For example they may look at a drug treatment for schizophrenia compared to having no medication (placebo).  The reviewers set about their task very methodically following, step by step, an advance plan (protocol) that covers:

• the way existing studies are found;
  
• how the relevant studies are judged in terms of their usefulness in answering the review question;
• how the results of the separate studies are brought together to give an overall measure of effectiveness (benefits and harms) – statistical techniques used to combine the results are called meta-analysis.

The protocol is the plan or set of steps to be followed in preparing a review. A protocol for a systematic review clearly describes why the review is needed (the review question), what the review is about (the healthcare context of the review), and how the reviewing authors will go about developing the review. It details how they will seek, select as relevant and judge the importance of the identified studies. The protocol also describes how they will collect and analyse the data.

Cochrane protocols are published in the Cochrane Database of Systematic Reviews so that people can comment on them before the actual review has been carried out. Once the review is started the authors must follow the protocol meticulously to minimise any preconceived notions they may have (bias). The protocol and a Cochrane handbook help them to do this.

Everyone (including scientists) have an opinion on most things. By following the details of a Cochrane protocol exactly, the bias produced by an individual’s views and judgments are reduced.  This is also why the collaboration concentrates on randomised control trials. A randomised controlled trial is a study that is rigorously designed. People are allocated to intervention groups in a way that minimises the chances of predicting which treatment group a study participant is in. The intervention under investigation (eg antipsychotic) is compared against a well-known intervention or an inactive treatment (placebo). Studies are controlled so that participants have similar associated care in all ways other than the intervention. Ideally, depending on the type of intervention, the service provider is unaware of which group a participant is in and those assessing outcomes are also unaware – this is called ’blinding’.

There are also very strict rules about what data can be used and how it is used.  Some trials are planned badly while others have not published all the data, even if they have recorded it for their own use.  When the reviewers look at the data, if it is not complete and the trial authors won’t give access to what extra data are needed, it cannot be used.  They will record this in the review.

Because healthcare studies differ dramatically in what they look for and how well they are carried out it is difficult to know how much weight one can put on their conclusions. Part of the reason for performing systematic reviews is to reduce the effects of these shortcomings. Issues of conflict of interest and corporate funding of healthcare studies are also important considerations in drawing conclusions from any study.

It is much more difficult to avoid bias in a qualitative study but discussions are underway in The Cochrane Collaboration as to how they can be used to add to the information obtained from  blinded controlled studies (whose outcomes are measured in numerical terms and so are termed quantitative studies). Qualitative measures include ‘quality of life’ and lifestyle changes obtained from detailed questionnaires. Qualitative studies may also use narrative interviews where participants are asked to talk about their experiences around sets of semi-structured questions and prompts to explore particular issues that information is needed on for a study. 

Read Janey's blog on the Cochrane reviews

The Cochrane Consumer Network supports service user participation within the Cochrane Collaboration internationally. The Network is available to any active consumer. Its mission is to enable and support consumers in contributing to the function of collaborative reviews groups and other Cochrane entities. The Network enables communication with other consumers, providing a sense of belonging within the Cochrane Collaboration, it also provides a way of broadcasting information from Cochrane reviews to people with health problems.

Cochrane reviews are scientific in the way they are produced and written.  However, each one has a ‘plain language summary’, a short description (under 400 words), about the background, methods, results and weaknesses of the review.  It is written in everyday English.  To make these summaries more accessible to people with mental health problems and their carers.

I will be writing them and will also write about some of my thoughts and feelings around what I have been reading and writing.   

• Read the plain English summaries.

Adapted from a paper by Consumers in Cochrane by Janey