Light–Dark and Activity Rhythm Therapy (L-DART) to Improve Sleep in People with Schizophrenia Spectrum Disorders: A Single-Group Mixed Methods Study of Feasibility, Acceptability and Adherence

Round 1

Reviewer 1 Report

The purpose of this article was to explore a new treatment method such as L-DART to improve sleep quality and alter abnormal circadian rhythm in the patients with schizophrenia spectrum disorders, and further to investigate non-drug intervention in some certain circumstances and sleep problem phenotypes in the future. After reading the manuscript, we found the article seemed to lack some important data including physical and mental examinations to evaluate sleep disorders in these patients. Therefore, some specific comments were listed below.

1.Sleep problems in people with schizophrenia include insomnia, sleep apnoea, hypersomnia and circadian activity disruptions, ect. However, the terms ‘insomnia’ and ‘circadian dysregulation’ are considered of both as symptoms and as signs. How to evaluate the both? In other words, the different classification (mild,moderate and severe) of insomnia as well as circadian dysregulation in these groups of patients should be addressed in-depth to avoid the statistic bias and to improve the article’s scientific value.

2.As described by the authors, it's a single group mixed method study with only 10 patients recruitment. The sample numbers seem to be too small to represent the objective results in the true world. It's suggested to further test L-DART in a larger randomised trial.

3.The fact that some objective (as anatomical abnormality including nasal septal deviation, tonsil hypertrophy, OSAHS, ect.) and subjective factors (as mental or psychological diseases) might influence people’s sleep conditions were obvious clinical and research results. To exclude these factors, it’s suggested to refer to other physicians or researchers to finish the study.

4.The whole manuscripts should pay much attention to novelty, it’s suggested to be published in a form of ‘letter to editor’ or ‘brief report’ if the present version was not revised.

The purpose of this article was to explore a new treatment method such as L-DART to improve sleep quality and alter abnormal circadian rhythm in the patients with schizophrenia spectrum disorders, and further to investigate non-drug intervention in some certain circumstances and sleep problem phenotypes in the future. After reading the manuscript, we found the article seemed to lack some important data including physical and mental examinations to evaluate sleep disorders in these patients. Therefore, some specific comments were listed below.

1.Sleep problems in people with schizophrenia include insomnia, sleep apnoea, hypersomnia and circadian activity disruptions, ect. However, the terms ‘insomnia’ and ‘circadian dysregulation’ are considered of both as symptoms and as signs. How to evaluate the both? In other words, the different classification (mild,moderate and severe) of insomnia as well as circadian dysregulation in these groups of patients should be addressed in-depth to avoid the statistic bias and to improve the article’s scientific value.

2.As described by the authors, it's a single group mixed method study with only 10 patients recruitment. The sample numbers seem to be too small to represent the objective results in the true world. It's suggested to further test L-DART in a larger randomised trial.

3.The fact that some objective (as anatomical abnormality including nasal septal deviation, tonsil hypertrophy, OSAHS, ect.) and subjective factors (as mental or psychological diseases) might influence people’s sleep conditions were obvious clinical and research results. To exclude these factors, it’s suggested to refer to other physicians or researchers to finish the study.

4.The whole manuscripts should pay much attention to novelty, it’s suggested to be published in a form of ‘letter to editor’ or ‘brief report’ if the present version was not revised.

Author Response

Thank you for this review, which was helpful, particularly for highlighting that we had given insufficient detail of the clinical assessment completed within the intervention.  We have revised the manuscript as shown in the tracked changes, and please find below our replies to your specific comments:

1.Sleep problems in people with schizophrenia include insomnia, sleep apnoea, hypersomnia and circadian activity disruptions, ect. However, the terms ‘insomnia’ and ‘circadian dysregulation’ are considered of both as symptoms and as signs. How to evaluate the both? In other words, the different classification (mild,moderate and severe) of insomnia as well as circadian dysregulation in these groups of patients should be addressed in-depth to avoid the statistic bias and to improve the article’s scientific value.

Re: We agree that more detail was needed regarding how the therapist assessed the patients before commencing goal setting and treatment and we have added a section describing this (2.6.1).

2.As described by the authors, it's a single group mixed method study with only 10 patients recruitment. The sample numbers seem to be too small to represent the objective results in the true world. It's suggested to further test L-DART in a larger randomised trial.

Re: We agree that to determine efficacy a larger RCT is needed, our aims in this study however were to make initial determinations of acceptability and feasibility of delivery of the intervention, which we are happy that we achieved to a reasonable level.  This approach of evaluating feasibility before completing an RCT is recommended by MRC complex interventions guidance. 

3.The fact that some objective (as anatomical abnormality including nasal septal deviation, tonsil hypertrophy, OSAHS, ect.) and subjective factors (as mental or psychological diseases) might influence people’s sleep conditions were obvious clinical and research results. To exclude these factors, it’s suggested to refer to other physicians or researchers to finish the study.

Re: This is a good point, as our intervention components were not designed to address physical causes of OSA such as nasal septal deviation.  We did include screening for OSA (now better described in the new section 2.6.1), we also excluded people where this was the primary complaint, and we did refer to other care providers as described in 3.4.5 when OSA was suspected.  In the cases referred we didn't find that anyone's sleep problems were totally explained by OSA, and we felt that addressing the behavioural factors, whilst also referring to physiological sleep specialists when this might be relevant, was one appropriate course of action.  We acknowledge the argument for ruling out OSA first, however as OSA and insomnia can interact (insomnia making it more difficult to acclimatise to CPAP), we found it was a reasonable approach to provide behavioural sleep treatment first in these cases, particularly as there was a significant wait for assessment for OSA by sleep services in our region at the time of the study.

4.The whole manuscripts should pay much attention to novelty, it’s suggested to be published in a form of ‘letter to editor’ or ‘brief report’ if the present version was not revised.

Re: We agree that a major feature of the work is novelty, not proof of effect.  We are pleased we were asked to revise not to convert the work to a letter however, as we feel this level of detail is needed to inform future studies.

Reviewer 2 Report

Overall this was good to read and I didn't see many problems. A few things that I think can be improved:

1. The introduction would benefit from a more comprehensive description of L-DART. After reading the introduction I don't know what this is, when it was developed, how effective it is supposed to be, how often it is used, whether there is existing literature around it, etc. 

2. "Custom measures" in the methods - please list somewhere all questions asked, not just an example, in the follow ups.

3. Minor: "...was relatively complete;, this is..." should be "...was relatively complete; this is..."

Author Response

Thank you for your review, which included useful suggestions.  We have revised the main text and Supplement S1.  Please find replies to your points.

1. The introduction would benefit from a more comprehensive description of L-DART. After reading the introduction I don't know what this is, when it was developed, how effective it is supposed to be, how often it is used, whether there is existing literature around it, etc. 

Re:  Thank you for noticing this, we did not properly introduce L-DART until the methods, which we agree is unhelpful for the reader.  We have re-phrased to make it clearer, and moved some content from the methods up into the introduction.  We still kept details around format and length in the methods as we didn't want to introduce repetition, hopefully the balance is better now.

2. "Custom measures" in the methods - please list somewhere all questions asked, not just an example, in the follow ups.

Re:  Apologies, we have added a list of questions asked into Supplement 1 and referenced this in the main text.  We have also described more fully the clinical assessment and formulation aspect of the intervention within the main text (section 2.6.1).

3. Minor: "...was relatively complete;, this is..." should be "...was relatively complete; this is..."

Re: Thank you for noticing this typo, amended.

Round 2

Reviewer 1 Report

The authors have given a careful one-to-one answer, but some of questions from the reviewer's comments wasn't completely replied mainly due to the initially experimental design at that time. Hopefully those questions will be further disscussed and verified to improve the whole article's scientific nature in the future.

The authors have given a careful one-to-one answer, but some of questions from the reviewer's comments wasn't completely replied mainly due to the initially experimental design at that time. Hopefully those questions will be further disscussed and verified to improve the whole article's scientific nature in the future.