Toxoplasma gondii Infection and Suicidal Behavior in People with Alcohol Consumption
Round 1
Reviewer 1 Report
- In tables likely better to refer to “History of suicidal ideation” or “Past suicidal ideation” or some other notation so that it is not implied that the ideation is current.
- Can the authors supply additional information regarding the sample? Is there no other sociodemographic information available such as educational attainment, socioeconomic status, etc.? Health variables? Current diagnoses? Were any being treated for psychiatric disorders? Other substance use or disorders? Did any meet criteria for an alcohol use disorder? Is this sample representative of the larger population from which it was collected? There were no additional exclusionary criteria? How were participants recruited and compensated? We need a lot more detail about the participants in order to draw conclusions as well as to replicate this finding.
- Why do you think the effect was not found in the middle group 31-50 years of age? This is not mentioned in the discussion.
- It is indicated in the Discussion that “Difference in the association among the studies could be due to differences in the characteristics of the study population.” Please add more detail here. I understand you may not know but you could discuss some possibilities given the factors that are associated with risk for toxoplasmosis and/or suicidal ideation.
Author Response
Reviewer #1:
- In tables likely better to refer to “History of suicidal ideation” or “Past suicidal ideation” or some other notation so that it is not implied that the ideation is current.
“History of suicidal ideation” was added to Tables 1 and 2.
- Can the authors supply additional information regarding the sample? Is there no other sociodemographic information available such as educational attainment, socioeconomic status, etc.? Health variables? Current diagnoses? Were any being treated for psychiatric disorders? Other substance use or disorders? Did any meet criteria for an alcohol use disorder? Is this sample representative of the larger population from which it was collected? There were no additional exclusionary criteria? How were participants recruited and compensated? We need a lot more detail about the participants in order to draw conclusions as well as to replicate this finding.
A new Table (Table 6) with sociodemographic characteristics of the study population was added (lines 235-236).
Information about the health of participants was added (lines 202-203).
No information about treatment of psychiatric disorders was obtained (lines 203).
None of the participants reported having an alcohol use disorder (lines 203-204).
According to the sample size calculation, the sample was representative of the larger population from which it was collected (lines 221-225).
Information about no restrictive criteria for enrollment was added (lines 195-196).
Information about recruitment of participants was added (lines 195-197).
- Why do you think the effect was not found in the middle group 31-50 years of age? This is not mentioned in the discussion.
The lack of association in the middle age group was discussed (lines 158-162).
- It is indicated in the Discussion that “Difference in the association among the studies could be due to differences in the characteristics of the study population.” Please add more detail here. I understand you may not know but you could discuss some possibilities given the factors that are associated with risk for toxoplasmosis and/or suicidal ideation.
Further discussion about the differences in the association among the studies was added (158-160).
Thank you for your valuable comments for improving our manuscript.
Reviewer 2 Report
Comments and Suggestions for Authors
The authors present a cross-sectional study on the possible association between T. gondii infection and suicidal behavior in people who drink alcohol in the population of Durango, Mexico.
1.-Introduction: In this manuscript the authors adequately present the generalities of the disease and the problem of the relationship of toxoplamosis and behavioral alterations and association with different mental illnesses. But it would be of great interest if it included a review of the epidemiological situation and seroprevalence of toxoplasmosis in the general population of Durango in order to better interpret what was identified in the group studied.
2.-Material and methods: Authors should complete and improve this section in various aspects. The study design is not sufficiently specified and presented. It is mentioned that a cross-sectional study is carried out during 5 years (2014-2019) in Durango, but it is not specified what type of population is carried out, where, how and in what way the study population is recruited and chosen, how many people have been studied by year, who has recruited them and on the basis of which organization, who has collected and reviewed the data.
The only important inclusion criterion established was a person with a history of alcohol consumption (at least one alcohol drink per month in the last 6 months). But this criterion is very broad and it is not specified whether people drank a lot (alcoholic people?), Or little (one alcoholic drink a month, which can be a beer, does not seem to indicate a high degree of alcohol), being difficult to assess . In the study: Has the information and data been taken in this regard? Has it been possible to stratify in terms of high, medium or low alcohol consumption? If so, this should be included in the manuscript and the study conducted with the results observed in this regard.
On the other hand, the criterion was established that it was of any gender and age over 15 years. But the authors have to specify how the selection was made, since the number of women included in the study was almost double that of men. What is the reason for this big difference?
The recruited subjects were given a questionnaire with sociodemographic data and data on suicidal behavior. The authors should include more information in this regard. Have the suicidal behaviors been in a short period of time prior to recruitment? If not, when performing the diagnostic tests for IgG and IgM against toxoplasma, the current results were obtained, but, Was it possible to know if at the time of the suicidal behavior they were already positive for Toxoplasma or not? This should be included in the manuscript and warned of possible bias.
Authors should include study limitations and confounding factors in the manuscript.,It is important to note in the manuscript possible biases and problems that have been found in the study.
-Results: The authors must take into account what has been indicated and commented on in the section on study design and methods, and review the results obtained including the different factors, applying the appropriate comparisons and statistical tests.
In addition to the results obtained in the population of subjects with alcohol consumption and suicidal behavior, observing the presence of toxoplasmosis or not in them, the situation and seroprevalence of toxoplasmosis in the general population of Durango should be known and taken into account and indicate if clear differences are seen, it would give more rigorous information.
-Discussion: In the discussion, the authors should take into account what has been indicated in the previous sections, show what was found and the biases, problems and limitations that could have been found in the study.
The comparison with the seroprevalence of the population of the Durango area in which the study was carried out and the epidemiological factors that are given to indicate the situation of toxoplasmosis in this área, should be highlighted.
The authors should discuss whether the greater association of toxoplasmosis and suicidal behavior in women than men who consume alcohol may also be due to other risk factors such as type of work, diet, contact with animals, etc.
It should also be discussed why it could be that the 30-50 age group did not show an association with suicidal behavior and toxoplasmosis.
And discuss the possible relationship of suicidal episodes with more or less alcohol consumption in addition to the presence of toxoplasmosis, if the data are available, and discuss the possibility of possible biases in this regard.
Also to discuss on the time of the serological analysis of toxoplasmosis carried out in the study, indicating whether it was at the time of having the episode of suicidal behavior or later. In toxoplasmosis positive cases, if it was the analysis later, the exact moment of contagion of the subject with Toxoplasma would be unknown, and there may be cases in which the contagion could be after the suicidal behavior, so it would not be known if this parasite influenced the behavior, modifying the interpretation of the results. For all this, it is important to know and include this information in the manuscript.
Due to the presence of interactions of different risk factors, and the absence of knowledge of data and characteristics that would be important to be able to determine with certainty the above, in this study it can be said that there are indications of a relationship ... and that new ones are necessary and more complete studies…. but a relationship should not be concluded in a categorical way.
Author Response
Reviewer #2:
1.-Introduction: In this manuscript the authors adequately present the generalities of the disease and the problem of the relationship of toxoplasmosis and behavioral alterations and association with different mental illnesses. But it would be of great interest if it included a review of the epidemiological situation and seroprevalence of toxoplasmosis in the general population of Durango in order to better interpret what was identified in the group studied.
Information about the seroprevalence of T. gondii infection in the general population of Durango City was added (lines 51-53).
2.-Material and methods: Authors should complete and improve this section in various aspects. The study design is not sufficiently specified and presented. It is mentioned that a cross-sectional study is carried out during 5 years (2014-2019) in Durango, but it is not specified what type of population is carried out, where, how and in what way the study population is recruited and chosen, how many people have been studied by year, who has recruited them and on the basis of which organization, who has collected and reviewed the data.
Information about recruitment of participants was added (lines 222-225).
The only important inclusion criterion established was a person with a history of alcohol consumption (at least one alcohol drink per month in the last 6 months). But this criterion is very broad and it is not specified whether people drank a lot (alcoholic people?), Or little (one alcoholic drink a month, which can be a beer, does not seem to indicate a high degree of alcohol), being difficult to assess . In the study: Has the information and data been taken in this regard? Has it been possible to stratify in terms of high, medium or low alcohol consumption? If so, this should be included in the manuscript and the study conducted with the results observed in this regard.
This study was exploratory, the quantity of alcohol consumption was not considered for analysis (lines 220-221).
The limitation of the study in correlating the quantity of alcohol consumption and suicidal behavior was added to the Discussion section (lines 204-215).
On the other hand, the criterion was established that it was of any gender and age over 15 years. But the authors have to specify how the selection was made, since the number of women included in the study was almost double that of men. What is the reason for this big difference?
Women were more willing to participate in the study than men (230-231).
The recruited subjects were given a questionnaire with sociodemographic data and data on suicidal behavior. The authors should include more information in this regard. Have the suicidal behaviors been in a short period of time prior to recruitment? If not, when performing the diagnostic tests for IgG and IgM against toxoplasma, the current results were obtained, but, Was it possible to know if at the time of the suicidal behavior they were already positive for Toxoplasma or not? This should be included in the manuscript and warned of possible bias.
We attempted to correlate the date of infection and the date of suicidal behavior (lines 121-127).
The limitation of the study in correlating the date of infection and the date of suicidal behavior was added to the Discussion section (lines 206-215).
Authors should include study limitations and confounding factors in the manuscript. It is important to note in the manuscript possible biases and problems that have been found in the study.
A paragraph with the limitations of the study was added to the Discussion section (lines 204-215).
-Results: The authors must take into account what has been indicated and commented on in the section on study design and methods, and review the results obtained including the different factors, applying the appropriate comparisons and statistical tests.
In addition to the results obtained in the population of subjects with alcohol consumption and suicidal behavior, observing the presence of toxoplasmosis or not in them, the situation and seroprevalence of toxoplasmosis in the general population of Durango should be known and taken into account and indicate if clear differences are seen, it would give more rigorous information.
The seroprevalence of T. gondii infection in the general population in Durango City was provided (lines 51-53).
The seroprevalence found in individuals with suicidal ideation in the current study was compared with the one reported in the general population in Durango City (145-147).
The seroprevalence found in individuals with suicide attempts in the current study was compared with the one reported in the general population in Durango City (172-175).
-Discussion: In the discussion, the authors should take into account what has been indicated in the previous sections, show what was found and the biases, problems and limitations that could have been found in the study.
The comparison with the seroprevalence of the population of the Durango area in which the study was carried out and the epidemiological factors that are given to indicate the situation of toxoplasmosis in this area, should be highlighted.
Comparison of the seroprevalences of T. gondii infection found in the current study and the one reported in the general population in Durango City was included in the manuscript (lines 145-147 and 172-175).
The authors should discuss whether the greater association of toxoplasmosis and suicidal behavior in women than men who consume alcohol may also be due to other risk factors such as type of work, diet, contact with animals, etc.
Discussion about difference of risk factors among women and men and its relationship with suicidal behavior was added (170-172).
It should also be discussed why it could be that the 30-50 age group did not show an association with suicidal behavior and toxoplasmosis.
The lack of association in the middle age group was discussed (lines 163-167).
And discuss the possible relationship of suicidal episodes with more or less alcohol consumption in addition to the presence of toxoplasmosis, if the data are available, and discuss the possibility of possible biases in this regard.
The limitation of the study in correlating the quantity of alcohol consumption and suicidal behavior was added to the Discussion section (lines 204-215).
Also to discuss on the time of the serological analysis of toxoplasmosis carried out in the study, indicating whether it was at the time of having the episode of suicidal behavior or later. In toxoplasmosis positive cases, if it was the analysis later, the exact moment of contagion of the subject with Toxoplasma would be unknown, and there may be cases in which the contagion could be after the suicidal behavior, so it would not be known if this parasite influenced the behavior, modifying the interpretation of the results. For all this, it is important to know and include this information in the manuscript.
The limitation of the study in correlating the time of having the episode of suicidal behavior and the serological analysis was added to the Discussion section (lines 204-215).
Due to the presence of interactions of different risk factors, and the absence of knowledge of data and characteristics that would be important to be able to determine with certainty the above, in this study it can be said that there are indications of a relationship ... and that new ones are necessary and more complete studies…. but a relationship should not be concluded in a categorical way.
Information about the need for further and more complete studies to determine the association between T. gondii exposure and suicidal behavior in alcohol consumers was added to the Discussion section (lines 209-215).
Thank you for your valuable comments for improving our manuscript.
