Sleep Disturbances in Patients with Persistent Delusions: Prevalence, Clinical Associations, and Therapeutic Strategies

Round 1

Reviewer 1 Report

This review is well composed and highlights relevant research as well as current gaps in the field. It specifically addresses sleep disturbances in relation to delusional disorder, which provides a novel perspective and therefore highlights an important issue.

It would benefit from some revisions, see below.

The article is well written, however the style could be improved, in some places it is slightly informal and unsuited to a scienfitic paper as lacks specificity, examples highlighted in the text.

I feel the title is misleading and does not reflect the content of the review, which largely discusses studies of illnesses related to DD rather than DD itself due to a lack of studies on DD. Please revise.

Pg. 3, line 82: I would disagree with the statement that evidence is sparse, for example in schizophrenia, sleep disturbances are well-documented. The statement suggests the authors have missed relevant studies, possibly by their method of literature search, in which their initial search was limited to the previous 2 years.

Line 94: "presumably because psychiatric conditions improved" - is there evidence for this? "Presumably" is unscientific. Other factors could have been involved e.g. adoption of regular routines such as mealtimes and light/dark cycle under a hospital environment leading to stabilisation of circadian rhythms.

Line 99: "sleep problems are more fundamental" - what is meant by "fundamental"? Be more specific.

Line 157: "The use of benzodiazepines for sleep was negatively correlated with quality of life" - please expand on this.

Line 184: "and presumably on medication" - please confirm whether this is the case or not.

Line 195: "found a prevalence rate of 23.3%" - is this in medicated individuals?

Line 197: "...social isolation, loneliness and a monotonous day routine" - good point, there was a study comparing schizophrenia patients to unemployed controls which would shed some light on this and worth mentioning - Wulff et al. 2012 Br. J. Psychiatry 200, 308–316. doi:10.1192/bjp.bp.111.096321.

Line 258 - please provide more details of the sleep disturbances in this patient.

Line 261 - "Medication was gradually changed to risperidone 6 mg/day" - from what?

Table 3 - this information would be better included in the main text rather than a table.

"4.1. Association of insomnia with paranoid ideation" - this section should be renamed or altered, as only one of the studies talked about seems to be specifically about paranoid symptoms and the others about psychosis more generally.

Line 322 & 324 - 'CD' - do you mean DD?

Line 364 "Antipsychotic medications are dopamine antagonists" - they are not exclusively, they also act on other neurotransmitter systems, please revise.

Line 369 - "...there will be more convincing evidence that sleep disturbance in DD patients is tied to treatment with AP drugs." - this is quite presumptive, while this is possible it is worth noting that in schizophrenia, sleep disturbances are known to occur independently of AP treatment, being present in prodromal stages and in unmedicated patients.

Table 4: It looks like there is a table formatting error with hypersomnia where the title should be? Also tables would benefit from being split into columns, e.g. in this table have one column for sleep condition and one for explanation. 

Line 395 - what about the psychotic symptoms? Any improvement?

Section '3.3. Sleep disturbances in delusional disorders': I would recommend re-structuring the article so that you put this near the start, and begin with the DD studies and then move on to talk about relevant evidence from studies on other mental illnesses, as DD is the focus of the review.

More variety of references are needed. In particular, the secton '3.2. Sleep disturbances in schizophrenia', predominantly focusses on one study by Reeve et al. 2019, but there are several other studies on this topic.

Comments for author File: Comments.pdf

Author Response

Thank you so much for your comments. The manuscript has greatly benefited from your recommendations.

 

This review is well composed and highlights relevant research as well as current gaps in the field. It specifically addresses sleep disturbances in relation to delusional disorder, which provides a novel perspective and therefore highlights an important issue.

It would benefit from some revisions, see below.

The article is well written, however the style could be improved, in some places it is slightly informal and unsuited to a scientific paper as lacks specificity, examples highlighted in the text.

Thank you for your positive comments. We appreciate your comments and have tried to be more specific and less informal.

 

(1)I feel the title is misleading and does not reflect the content of the review, which largely discusses studies of illnesses related to DD rather than DD itself due to a lack of studies on DD. Please revise.

We entirely agree.

New title: “Sleep Disturbances in Patients with Chronic Delusions: Prevalence, Clinical Associations and Therapeutic Strategies”

 

(2)Pg. 3, line 82: I would disagree with the statement that evidence is sparse, for example in schizophrenia, sleep disturbances are well-documented. The statement suggests the authors have missed relevant studies, possibly by their method of literature search, in which their initial search was limited to the previous 2 years.

We have now clarified that what is sparse is knowledge about the neurobiological basis for the overlap between sleep disorder and psychiatric illness. We have tried to stay with the very recent literature and apologize for omitting important earlier work.

 

(3)Line 94: "presumably because psychiatric conditions improved" - is there evidence for this? "Presumably" is unscientific. Other factors could have been involved e.g. adoption of regular routines such as mealtimes and light/dark cycle under a hospital environment leading to stabilization of circadian rhythms.

We have changed the wording and added other potential explanations as recommended.

 

(4)Line 99: "sleep problems are more fundamental" - what is meant by "fundamental"? Be more specific. 

We changed the term to foundational, meaning that there would be no PTSD if sleep were not disturbed.

 

(5)Line 157: "The use of benzodiazepines for sleep was negatively correlated with quality of life" - please expand on this.

As recommended, we have expanded this paragraph.

 

(6)Line 184: "and presumably on medication" - please confirm whether this is the case or not.

We have clarified this point. Patients were diagnosed with schizophrenia and were on medication.

 

(7)Line 195: "found a prevalence rate of 23.3%" - is this in medicated individuals?

This prevalence is in the context of patients who received medication. We have now clarified this point.

 

(8)Line 197: "...social isolation, loneliness and a monotonous day routine" - good point, there was a study comparing schizophrenia patients to unemployed controls which would shed some light on this and worth mentioning - Wulff et al. 2012 Br. J. Psychiatry 200, 308–316. doi:10.1192/bjp.bp.111.096321.

Thank you so much for this excellent reference, which has been included and discussed.

 

(9)Line 258 - please provide more details of the sleep disturbances in this patient.

A more detailed description is now included.

 

(10)Line 261 - "Medication was gradually changed to risperidone 6 mg/day" - from what?

This issue has now been clarified.

 

(11)Table 3 - this information would be better included in the main text rather than a table.

We have removed this Table and the information it contained is now in the main text. The Tables have been renumbered.

 

(12)"4.1. Association of insomnia with paranoid ideation" - this section should be renamed or altered, as only one of the studies talked about seems to be specifically about paranoid symptoms and the others about psychosis more generally.

We have changed the heading of this section to: Association of insomnia with psychotic symptoms.

 

(13)Line 322 & 324 - 'CD' - do you mean DD?

CD refers to comorbid depression in patients with delusional disorder. We have included CD in brackets after the words “comorbid depression”. Thanks for bringing this to our attention.

 

(14)Line 364 "Antipsychotic medications are dopamine antagonists" - they are not exclusively, they also act on other neurotransmitter systems, please revise.

Thank you. The sentence has been revised. No exclusivity was intended.

 

(15)Line 369 - "...there will be more convincing evidence that sleep disturbance in DD patients is tied to treatment with AP drugs." - this is quite presumptive, while this is possible it is worth noting that in schizophrenia, sleep disturbances are known to occur independently of AP treatment, being present in prodromal stages and in unmedicated patients.

Absolutely. Sleep disturbances can occur in everyone. Both psychosis and medication can, in individual cases, be partially responsible. This has been clarified.

 

(16)Table 4: It looks like there is a table formatting error with hypersomnia where the title should be? Also tables would benefit from being split into columns, e.g. in this table have one column for sleep condition and one for explanation.

We have corrected this formatting error and have added a new column to separate the sleep condition and the explanation.

 

(17)Line 395 - what about the psychotic symptoms? Any improvement?

We have added information - CBT was associated with an improvement of sleep disorders, paranoia, and hallucinatory experiences.

 

(18)Section '3.3. Sleep disturbances in delusional disorders': I would recommend re-structuring the article so that you put this near the start, and begin with the DD studies and then move on to talk about relevant evidence from studies on other mental illnesses, as DD is the focus of the review.

We have changed the title to clarify that the review addresses the association of sleep disturbances with the presence of  chronic delusions.  We progress from the general to the specific - sleep disorders in mental disorders, sleep disturbances in psychoses, sleep disorders in delusional disorder. From there we progress to individual symptoms and their treatment.

 

(19)More variety of references are needed. In particular, the section '3.2. Sleep disturbances in schizophrenia', predominantly focusses on one study by Reeve et al. 2019, but there are several other studies on this topic.

We have added relevant recent references.

We have added a short paragraph in (3.2.) to better introduce these references.

 

Reviewer 2 Report

Manuscript entitled „Sleep Disturbances in Patients with Delusional Disorder: Prevalence, Clinical Implications and Therapeutic Strategies” undertakes a very important and current topic – the relationship between the psychiatric disorders and sleep.

The manuscript is very well written and precisely describes the multiple sleep disturbances that might present with psychotic disorders.

It could be interesting to add a short note on the possibility of differences ion objective sleep examination, which is the polysomnography. For example, the spectral power differences and similarities between the findings in individuals which psychiatric diseases and healthy individuals might be interesting (doi: 10.1111/jsr.12848, doi: j.jpsychires.2005.01.002, doi: 10.5664/jcsm.7036).

 

 

 

 

Author Response

Thank you so much for suggesting two very relevant references. The manuscript is now very much improved.

Manuscript entitled „Sleep Disturbances in Patients with Delusional Disorder: Prevalence, Clinical Implications and Therapeutic Strategies” undertakes a very important and current topic – the relationship between the psychiatric disorders and sleep.

 

The manuscript is very well written and precisely describes the multiple sleep disturbances that might present with psychotic disorders.

 

Thank you for your positive comments.

 

(1)It could be interesting to add a short note on the possibility of differences ion objective sleep examination, which is the polysomnography. For example, the spectral power differences and similarities between the findings in individuals which psychiatric diseases and healthy individuals might be interesting (doi: 10.1111/jsr.12848, doi: j.jpsychires.2005.01.002, doi: 10.5664/jcsm.7036).

These two references have been added.

The first is referenced in the section on the treatment of delusional disorders. The second has been included in the discussion section to underscore the fact that further research is needed to elucidate differences between subjective sleep quality and objective sleep disturbances.