International and Spanish Findings in Scientific Literature about Minors’ Mental Health: Predictive Factors Using the Strengths and Difficulties Questionnaire

Abstract

Regarding the explanatory variables of mental health in children and adolescents, several studies within the Spanish context have focused their attention on analysis of the influence of variables such as age, gender, occupational social class of parents, or perceived physical health [13,14,15,16]. In addition to the 2006 Spanish National Health Survey, ENSE 2006 [13,15,38,39], it has also been used in subsequent counterpart studies, ENSE 2011-2012 [14,34]. [...]it can be concluded that the SDQ-parent is an internationally recognized instrument with excellent quality for the screening of children with problems or difficulties in mental health [40]. [...]there is an extended version of the SDQ with an impact supplement, to better explore the child’s or adolescent’s social difficulties. Influence of Gender and Age on Mental Health Regarding the influence of the variable of gender on mental health during childhood and adolescence in Spain, we find that in most of the studies reviewed, independently of which SDQ version was used, i.e., the parent’s version or self-reported version, females tend to score higher in internalized symptoms, such as emotional problems and also at the prosocial behavior subscale, whereas males score higher in external symptoms, such as behavioral problems and hyperactivity [14,34,38,42].

1. Introduction

The analysis of minors’ mental health has become a topic of research of global interest, with recent international contributions from all continents: Africa [1], Europe [2], Asia [3], Oceania [4], and America [5]. Overall, it is estimated that between 10% and 20% of minors suffer from mental health problems [6]. A recent meta-analysis of 41 studies in 27 countries, with a total of 87,742 children, established a worldwide prevalence of 13.4% in children and adolescents, with 12.36% in children aged specifically between 6 and 11 years [7].

On the other hand, it has been shown that half of adults’ disorders have their beginning in adolescence [8]. Despite this, more than half of the children with mental problems do not receive specialized treatment in mental health [9]. In turn, some international studies have shown a greater proportional increase in mental health disorder diagnoses in the juvenile population compared to adults although, in both cases, there was an augmentation in the use of psychiatric medication [10]. This increase in the number of mental health problems in children [6], especially in Western countries [11,12], implies a clear need to analyze mental health in the early stages, not only to improve intervention, but also as a preventative approach.

Regarding the explanatory variables of mental health in children and adolescents, several studies within the Spanish context have focused their attention on analysis of the influence of variables such as age, gender, occupational social class of parents, or perceived physical health [13,14,15,16]. The early identification of these variables can be beneficial in helping to avoid emotional and behavioral problems that can also be aggravated at later stages of life. This paper presents an analysis of mental health associated with these variables in the Spanish population compared to the international scientific literature. In turn, an analysis of the usefulness of the Strengths and Difficulties Questionnaire (SDQ), to measure the mental health of the population between 4 and 16 years old, is presented.

2. Materials and Methods 2.1. Evaluation of Minors: Use of the Strengths and Difficulties Questionnaire

Since the second half of the twentieth century, attempts have been made to measure the population health of some countries through national health surveys [17]. Unfortunately, in the beginning, the diversity of methodologies and instruments made it difficult to compare results internationally [7]. However, thanks to the introduction of internationally validated questionnaires into the scientific community, samples can be compared and more global analyses carried out [2]. In this sense, the international agreement for the application of the Strengths and Difficulties Questionnaire (SDQ) [18], or the measurement of mental health, has represented an advance in research coordination within the scientific community [19], always with the precaution of the possible effects that cultural differences may have on the results [20,21]. This questionnaire has been validated internationally [4,15,22,23,24,25] and has been used in a multitude of studies to measure mental health both longitudinally [4,26], and transversally [14,27]. It has proven to be an excellent screening tool compared to other more classic tools, such as the Child Behavior Checklist (CBCL) [28,29]. At the same time, its ease of use and internal structure make it very attractive for research [22,30]. It has demonstrated good use in detecting probable cases of psychological problems in European children, with good psychometric properties across seven European countries [31]. A systematic review by Kersten et al. showed interesting comparative information of the psychometric properties obtained in several studies, using the teacher and parent version of the SDQ [32]. It consists of five subscales of five items each. The total score for difficulties or mental health problems is calculated using the sum of the subscales of conduct problems, emotional problems, peer relationship problems, and hyperactivity [22], ranging from 0 to 40 points. The fifth subscale, prosocial behavior, is not considered for the valuation of the total score. Regarding the psychometric properties of the SDQ, one recent systematic review by Ortuño-Sierra et al. [19] shows that most studies prove the existence of five solid and well-defined factors that correspond to the SDQ subscales. This review describes more than 50 international studies, carried out between 2000 and 2015, that analyze the validity of the questionnaire construct by means of exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). On the one hand, the values that achieve goodness of fit in the five-factor model (emotional symptoms, conduct problems, peer relationship problems, hyperactivity, and prosocial behavior) are found; although, some studies found goodness of fit in the two-factor second-order model [33]. On the other hand, regarding the reliability of the SDQ, it can be pointed out that the total score, as well as the subscales of emotional symptoms, conduct problems, peer relationship problems, hyperactivity, and prosocial behavior, show good internal consistency, whereas the conduct problems and peer relationship problem subscales present more discrete Cronbach’s alpha values [19]. This questionnaire also allows the use of two factors, internalizing (sum of the emotional problems and peer relationship problems subscales) and externalizing factors (conduct problems and hyperactivity) [34], and could be a good screening tool for attention-deficit/hyperactivity disorder (ADHD) [35]. However, recent studies with the SDQ-parent version in the Spanish population highlight that a structure of five factors is the best choice, avoiding bifactorial use [34]. However, the different structures found could explain the manifestation of psychological difficulties in children and adolescent populations. The questionnaire allows the use of different versions depending on the sample, self-report for adolescents between 11 and 16 years old, and the versions for parents and teachers, and for children from 4 to 16 years old. The self-report version is recommended for people over 11 years old [36] although good psychometric qualities have also been obtained when it was used with children between 8 and 13 years old [37]. Even so, the parent version is the most commonly used for measuring the mental health of Spanish children [38]. In Spain, it was introduced for the first time in the National Health Survey of 2006 to study the mental health of children. In addition to the 2006 Spanish National Health Survey, ENSE 2006 [13,15,38,39], it has also been used in subsequent counterpart studies, ENSE 2011-2012 [14,34]. Therefore, it can be concluded that the SDQ-parent is an internationally recognized instrument with excellent quality for the screening of children with problems or difficulties in mental health [40]. The most recent studies recommend the use of more than one version at the same time, for example, using both the parental and self-reported versions [36]. Finally, there is an extended version of the SDQ with an impact supplement, to better explore the child’s or adolescent’s social difficulties. It explores four domains: friendships, classroom learning, home life, and leisure activities (not for teacher or caregiver) [41]. New questions for use after interventions are introduced in the follow-up versions of the SDQ (https://www.sdqinfo.org).

2.2. Influence of Gender and Age on Mental Health

Regarding the influence of the variable of gender on mental health during childhood and adolescence in Spain, we find that in most of the studies reviewed, independently of which SDQ version was used, i.e., the parent’s version or self-reported version, females tend to score higher in internalized symptoms, such as emotional problems and also at the prosocial behavior subscale, whereas males score higher in external symptoms, such as behavioral problems and hyperactivity [14,34,38,42]. These results converge with the outcomes from a large volume of studies obtained with samples from other countries [25,40,43,44,45,46,47,48,49,50].

However, it has also been observed, in some Spanish studies, that there were no apparent significant differences in terms of gender [15,51] or, specifically, in relation to the dimension of peer relationship problems [38]. In another study using an international sample [40], no significant gender differences were observed regarding internalizing disorders, though a greater prevalence was found in adolescent females compared to males. In this study, males hyperactivity/inattention and conduct disorder were also consistently associated with a higher probability of disorders [52]. These differences could be related to a lack of clear diagnosis criteria, as well as the actual diversity of evaluation methodologies for measuring pathological symptoms in boys and girls [13,15].

Regarding the variable age, no conclusive general findings were shown in the reviewed Spanish studies. This is consistent with other previous works [14,53]. Taking into account specific measures on the different SDQ dimensions, some of the analyzed studies point out that females emotional problems scores increase with age, and scores in hyperactivity and conduct problems were lower in the older age group in the total sample, whereas scores in prosocial behaviors were higher in the older age group for the total sample [38]. However, when comparing age groups, other studies reveal that the elder group (14–18 years) presents higher scores in emotional, conduct, and hyperactivity problems, as well as the Total Difficulties Score, than the younger group [54]. In this sense, some international studies found a growing tendency in symptomatology as subjects grew up [25,44,50], whereas others found a reverse tendency [13,45,48] or no association [11,55].

2.3. Physical State of the Minor and Mental Health

The association between perceived physical health and mental health in children and adolescents has also been studied in the Spanish population through the SDQ [15]. Several international studies have shown how healthy lifestyles are associated with a lower risk of suffering from mental disorders [56]. In this regard, it is worth mentioning the importance of regular physical activity as a precursor to good physical and mental health [57]. Thus, it has been found that levels of obesity and physical activity practice can predict mental health states in Spanish children and adolescents [58]. In this way, participation in extracurricular sports activities has also been shown as a variable associated with good mental health, especially in the case of boys [59]. From another point of view, recent Spanish studies show how perceived poor physical health may favor the possibility of suffering mental health problems [13,15,54]. These results have also been supported in other international investigations demonstrating that poor physical health is a risk factor for mental health [60,61].

2.4. Occupational Social Class and Educational Level of Parents Associated with Minor’s Mental Health

Mentioned below are the main Spanish studies on family variables and mental health measured through the SDQ. This analysis summarizes the results according to various factors, such as the level of academic studies and occupational social class. The results of these Spanish studies show a strong association between parent education and child mental health as informed by the parents [62,63]. Likewise, the children of mothers with a primary education level have worse mental health than the children of mothers with university studies [64], with a high level of education being considered a factor that reduces children’s mental health problems [65]. These results, obtained from the general population of Spanish minors, agree with international research that demonstrates an association between the low level of training and socioeconomic status of parents, and with a minor’s poor mental health [66,67,68]. This association is still present in the last European Health Survey in Spain (EHSS 2014) and, more globally, in the most recent European Health Interview Survey (EHIS) [69].

Regarding the occupational social class, this category has been classified in Spain according to the proposal of the Spanish Society of Epidemiology’s Working Group (SEE) [70], or according to the Spanish adaptation of the British General Registrar’s classification [13]. For a simpler comparative analysis, the occupational class is usually divided into three types: high, medium, and low class. The results show how the jobs of the main breadwinner in lower categories are more strongly related to the presence of mental health problems in children [63,71]. On the contrary, it is the families with jobs corresponding to the middle classes and the most privileged classes that suppose a protective factor against the more disadvantaged classes concerning the presence of mental health problems in minors [14,62,63,64]. These data, obtained from the general population of Spanish minors, agree with other international research that shows that children from families with a poorer socioeconomic status have worse physical and mental health than minors with a high socioeconomic level [68,72,73,74].

2.5. Family Variables and Mental Health of Minor’s Family Variables and Minor’s Mental Health

Family variables have been shown to be of great importance in the minor’s mental health [13,16]. The parent’s mental health [60] and socioeconomic status [39], or the children’s healthcare [15], are some of the variables that have proven to be determining factors. Other variables that have been shown to be significant for a child’s inadequate mental health have been the type of single-parent family [37,62,63], as well as the presence of other relatives in situations of unemployment [65]. Likewise, the influence of poor mental health of the parents [63] and, specifically, of the mother [65], has been analyzed as a determining variable for the development of the mental well-being of their children. These results coincide with other international research that shows how parent’s inadequate mental health negatively affects the health of their children [60,75]. With respect to Spain, the main research on family variables and mental health, as measured with the SDQ, has used the total or partial sample and data from the National Health Survey ENSE 2006 and/or ENSE 2012. This has had great advantages regarding ensuring of the validity of sources or external evidence, and the generalization of the results in Spain but, in turn, has been limited regarding the objectives of the research. The methodology and sample size of these surveys, representative of the entire Spanish population, are a great advantage. However, only the parent version of the SDQ has been used, and the level of studies, social class, and parental health have been analyzed mainly as family variables. In this sense, it is advisable to advance the research using other versions of the SDQ in Spain, such as the self-report with children from the age of 11. Likewise, there are other variables, such as family relationships, from the point of view of family violence, either between parents [76], or from parents to children [77], that should also be analyzed. In this sense, the theory of parental rejection acceptance [78] could be interesting for analyzing the influence of parental affections on their children, and how these perceptions or experiences can affect the cognitive and socioemotional adjustment of minors [79]. It is known that lack of affection on the part of the mother, together with rejection from the father, can be related to a greater probability of aggressive behaviors in situations of bullying [80], causing, in turn, the minor’s mental health problems involved in these behaviors [81]. Even so, more studies are needed to analyze the filioparental relationships of affection/rejection and its relationship with the minor’s mental health.

3. Conclusions

The global situation of minors’ mental health is alarming. The high figures, where 2 out of 8 children suffer from these pathologies, indicate the relevance of this theme. In this study, the SDQ questionnaire is shown to be a recognized and recommended international tool for the measurement of mental health problems of minors both in Spain and internationally. In turn, a middle and high social class and educational level of parents has been shown to be a preventive factor of mental health problems of minors both in Spain and internationally. Similarly, good physical health of the child is shown as a factor associated with good mental health in both Spanish and international studies. Regarding gender and age, there are studies that associate externalizing symptoms to the masculine gender and internalizing to the feminine, although there is still a need for more international studies that clarify the diversity of currently published results. In turn, complementary studies that analyze, in greater depth, the family affective relationships between parents and children as an influential factor in mental health seem necessary. Similarly, an analysis of the variables associated with sedentary lifestyle, such as online gaming, should be researched in a greater number of studies, in order to understand their possible influence on the relationship between physical health and mental health in minors, using the SDQ. Finally, in accordance with other researchers [19], we also consider it reasonable that advances in the detection of factors associated with the mental health of minors will have repercussions in different areas—medical, psychological, and academic—in addition to influencing public policies, due to the active pursuit of these advances by patients and relatives.

Author Contributions

F.F.-B. is the principal author, contributed to the literature review, the writing and reviewing the manuscript. I.R.-G. contributed to the literature review, made the translation and editing of the manuscript. D.I.G, E.J.R.d.S. and B.L.-d.B. contributed to the literature review.

Funding

This work has been funded by the support to Consolidation of Research Groups (Junta de Extremadura GR18091/18.HJ.11). The authors would like to thank their support.

Conflicts of Interest

The authors declare no conflict of interest.

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

References

1. Mellins, C.A.; Xu, Q.; Nestadt, D.F.; Knox, J.; Kauchali, S.; Arpadi, S.; Kvalsvig, J.; Shrout, P.E.; Davidson, L.L. Screening for mental health among young South African children: The use of the strengths and difficulties questionnaire (SDQ). Glob. Soc. Welf. 2018, 5, 29-38.

2. Iguacel, I.; Michels, N.; Fernández-Alvira, J.M.; Bammann, K.; De Henauw, S.; Felső, R.; Gwozdz, W.; Hunsberger, M.; Reisch, L.; Russo, P.; et al. Associations between social vulnerabilities and psychosocial problems in European children. Results from the IDEFICS study. Eur. Child Adolesc. Psychiatry 2017, 26, 1105-1117.

3. Ranasinghe, S.; Ramesh, S.; Jacobsen, K.H. Hygiene and mental health among middle school students in India and 11 other countries. J. Infect. Public Health 2016, 9, 429-435. [Green Version]

4. Christensen, D.; Fahey, M.T.; Giallo, R.; Hancock, K.J. Longitudinal trajectories of mental health in Australian children aged 4-5 to 14-15 years. PLoS ONE 2017, 12, e0187974.

5. Aakre, J.M.; Lucksted, A.; Browning-McNee, L.A. Evaluation of youth mental health first aid USA: A program to assist young people in psychological distress. Psychol. Serv. 2016, 13, 121-126.

6. Kieling, C.; Baker-Henningham, H.; Belfer, M.; Conti, G.; Ertem, I.; Omigbodun, O.; Rohde, L.A.; Srinath, S.; Ulkuer, N.; Rahman, A. Child and adolescent mental health worldwide: Evidence for action. Lancet 2011, 378, 1515-1525.

7. Polanczyk, G.V.; Salum, G.A.; Sugaya, L.S.; Caye, A.; Rohde, L.A. Annual research review: A meta-analysis of the worldwide prevalence of mental disorders in children and adolescents. J. Child Psychol. Psychiatry 2015, 56, 345-365.

8. Belfer, M.L. Child and adolescent mental disorders: The magnitude of the problem across the globe. J. Child Psychol. Psychiatry Allied Discip. 2008, 49, 226-236.

9. Merikangas, K.R.; Nakamura, E.F.; Kessler, R.C. Epidemiology of mental disorders in children and adolescents. Dialogues Clin. Neurosci. 2009, 11, 7-20.

10. Olfson, M.; Blanco, C.; Wang, S.; Laje, G.; Correll, C.U. National trends in the mental health care of children, adolescents, and adults by office-based physicians. JAMA Psychiatry 2014, 71, 81.

11. Rajmil, L.; de Sanmamed, M.-J.; Choonara, I.; Faresjö, T.; Hjern, A.; Kozyrskyj, A.; Lucas, P.; Raat, H.; Séguin, L.; Spencer, N.; et al. Impact of the 2008 economic and financial crisis on child health: A systematic review. Int. J. Environ. Res. Public Health 2014, 11, 6528-6546.

12. Perou, R.; Bitsko, R.H.; Blumberg, S.J.; Pastor, P.; Ghandour, R.M.; Gfroerer, J.C.; Hedden, S.L.; Crosby, A.E.; Visser, S.N.; Schieve, L.A.; et al. Mental health surveillance among children-United States, 2005-2011. Morb. Mortal. Wkly. Report Surveill. Summ. 2013, 62, 1-35.

13. Fajardo-Bullón, F.; León del Barco, B.; Felipe-Castaño, E.; Polo del Río, M.I.; Santos, E. Mental health in Spanish minors. Socioeducational variables. Salud Ment. 2015, 38, 329-335.

14. Fajardo-Bullón, F.; Rasskin-Gutman, I.; Felipe-Castaño, E.; Santos, E.J.; León-del Barco, B. Analysis of Predictive factors on minors' mental health according to the spanish national health survey. Brain Sci. 2017, 7, 135.

15. Fajardo Bullón, F.; León Del Barco, B.; Felipe Castaño, E.; Ribeiro Dos Santos, E.J. Mental health in the age group 4-15 years based on the results of the national survey of health 2006, Spain. Rev. Esp. Salud Publica 2012, 86, 445-451.

16. León-del-Barco, B.; Fajardo-Bullón, F.; Mendo-Lázaro, S.; Rasskin-Gutman, I.; Iglesias-Gallego, D. Impact of the familiar environment in 11-14-year-old minors' mental health. Int. J. Environ. Res. Public Health 2018, 15, 1314.

17. Buka, S.L.; Monuteaux, M.C.; Earls, F.J. The epidemiology of child and adolescent mental disorders. In Textbook in Psychiatric Epidemiology; Tsuang, M.T., Tohen, M., Eds.; John Wiley & Sons: New York, NY, USA, 2002; pp. 629-655.

18. Goodman, R. The strengths and difficulties questionnaire: A research note. J. Child Psychol. Psychiatry Allied Discip. 1997, 38, 581-586.

19. Ortuño-Sierra, J.; Fonseca-Pedrero, E.; Inchausti, F.; Sylvia Sastrei, R. Assessing behavioural and emotional difficulties in the child-adolescent population: The strenghts and difficulties questionnaire (SDQ). Pap. Psicol. 2016, 37, 14-26.

20. Pincus, H.A.; Spaeth-Rublee, B. Quality of mental healthcare. Neuropsychiatry 2012, 2, 13-17.

21. Goodman, A.; Heiervang, E.; Fleitlich-Bilyk, B.; Alyahri, A.; Patel, V.; Mullick, M.S.I.; Slobodskaya, H.; dos Santos, D.N.; Goodman, R. Cross-national differences in questionnaires do not necessarily reflect comparable differences in disorder prevalence. Soc. Psychiatry Psychiatr. Epidemiol. 2012, 47, 1321-1331.

22. Goodman, A.; Goodman, R. Population mean scores predict child mental disorder rates: Validating SDQ prevalence estimators in Britain. J. Child Psychol. Psychiatry Allied Discip. 2011, 52, 100-108.

23. Shibata, Y.; Okada, K.; Fukumoto, R.; Nomura, K. Psychometric properties of the parent and teacher forms of the Japanese version of the strengths and difficulties questionnaire. Brain Dev. 2015, 37, 501-507.

24. Stone, L.L.; Otten, R.; Engels, R.C.M.E.; Vermulst, A.A.; Janssens, J.M.A.M. Psychometric properties of the parent and teacher versions of the strengths and difficulties questionnaire for 4-12-year-olds: A review. Clin. Child Fam. Psychol. Rev. 2010, 13, 254-274.

25. Giannakopoulos, G.; Tzavara, C.; Dimitrakaki, C.; Kolaitis, G.; Rotsika, V.; Tountas, Y. The factor structure of the strengths and difficulties questionnaire (SDQ) in Greek adolescents. Ann. Gen. Psychiatry 2009, 8, 20.

26. Ford, T.; Collishaw, S.; Meltzer, H.; Goodman, R. A prospective study of childhood psychopathology: Independent predictors of change over three years. Soc. Psychiatry Psychiatr. Epidemiol. 2007, 42, 953-961.

27. Arman, S.; Keypour, M.; Maracy, M.R.; Attari, A. Epidemiological study of youth mental health using strengths and difficulties questionnaire (SDQ). Iran Red Crescent Med. J. 2012, 14, 371-375.

28. Goodman, R.; Scott, S. Comparing the strengths and difficulties questionnaire and the child behavior checklist: Is small beautiful? J. Abnorm. Child Psychol. 1999, 27, 17-24.

29. Goodman, A.; Goodman, R. Strengths and difficulties questionnaire as a dimensional measure of child mental health. J. Am. Acad. Child Adolesc. Psychiatry 2009, 48, 400-403.

30. Goodman, R. Psychometric properties of the strengths and difficulties questionnaire. J. Am. Acad. Child Adolesc. Psychiatry 2001, 40, 1337-1345.

31. Husky, M.M.; Boyd, A.; Bitfoi, A.; Carta, M.G.; Chan-Chee, C.; Goelitz, D.; Koç, C.; Lesinskiene, S.; Mihova, Z.; Otten, R.; et al. Self-reported mental health in children ages 6-12 years across eight European countries. Eur. Child Adolesc. Psychiatry 2018, 27, 785-795.

32. Kersten, P.; Czuba, K.; McPherson, K.; Dudley, M.; Elder, H.; Tauroa, R.; Vandal, A. A systematic review of evidence for the psychometric properties of the strengths and difficulties questionnaire. Int. J. Behav. Dev. 2016, 40, 64-75.

33. Caci, H.; Morin, A.J.S.; Tran, A. Investigation of a bifactor model of the strengths and difficulties questionnaire. Eur. Child Adolesc. Psychiatry 2015, 24, 1291-1301.

34. Ortuño-Sierra, J.; Aritio-Solana, R.; Fonseca-Pedrero, E. Mental health difficulties in children and adolescents: The study of the SDQ in the Spanish national health survey 2011-2012. Psychiatry Res. 2018, 259, 236-242.

35. Algorta, G.P.; Dodd, A.L.; Stringaris, A.; Youngstrom, E.A. Diagnostic efficiency of the SDQ for parents to identify ADHD in the UK: A ROC analysis. Eur. Child Adolesc. Psychiatry 2016, 25, 949-957.

36. Gaete, J.; Montero-Marin, J.; Valenzuela, D.; Rojas-Barahona, C.A.; Olivares, E.; Araya, R. Mental health among children and adolescents: Construct validity, reliability, and parent-adolescent agreement on the "Strengths and Difficulties Questionnaire" in Chile. PLoS ONE 2018, 13, e0191809.

37. Muris, P.; Meesters, C.; Eijkelenboom, A.; Vincken, M. The self-report version of the strengths and difficulties questionnaire: Its psychometric properties in 8-13-year-old non-clinical children. Br. J. Clin. Psychol. 2004, 43, 437-448.

38. Barriuso-Lapresa, L.M.; Hernando-Arizaleta, L.; Rajmil, L. Reference values of the strengths and difficulties questionnaire (SDQ) version for parents in the Spanish population, 2006. Actas Esp. Psiquiatr. 2014, 42, 43-48.

39. Gómez-Beneyto, M.; Nolasco, A.; Moncho, J.; Pereyra-Zamora, P.; Tamayo-Fonseca, N.; Munarriz, M.; Salazar, J.; Tabarés-Seisdedos, R.; Girón, M. Psychometric behaviour of the strengths and difficulties questionnaire (SDQ) in the Spanish national health survey 2006. BMC Psychiatry 2013, 13, 95.

40. Kovess-Masfety, V.; Husky, M.M.; Keyes, K.; Hamilton, A.; Pez, O.; Bitfoi, A.; Carta, M.G.; Goelitz, D.; Kuijpers, R.; Otten, R.; et al. Comparing the prevalence of mental health problems in children 6-11 across Europe. Soc. Psychiatry Psychiatr. Epidemiol. 2016, 51, 1093-1103. [Green Version]

41. Janssens, A.; Deboutte, D. Screening for psychopathology in child welfare: The strengths and difficulties questionnaire (SDQ) compared with the achenbach system of empirically based assessment (ASEBA). Eur. Child Adolesc. Psychiatry 2009, 18, 691-700.

42. Ortuño-Sierra, J.; Fonseca-Pedrero, E.; Paino, M.; Sastre i Riba, S.; Muñiz, J. Screening mental health problems during adolescence: Psychometric properties of the Spanish version of the strengths and difficulties questionnaire. J. Adolesc. 2015, 38, 49-56.

43. Göran Svedin, C.; Priebe, G. The strengths and difficulties questionnaire as a screening instrument in a community sample of high school seniors in Sweden. Nord. J. Psychiatry 2008, 62, 225-232.

44. Koskelainen, M.; Sourander, A.; Vauras, M. Self-reported strengths and difficulties in a community sample of Finnish adolescents. Eur. Child Adolesc. Psychiatry 2001, 10, 180-185.

45. Muris, P.; Meesters, C.; van den Berg, F. The strengths and difficulties questionnaire (SDQ). Eur. Child Adolesc. Psychiatry 2003, 12, 1-8.

46. Riso, D.D.; Salcuni, S.; Chessa, D.; Raudino, A.; Lis, A.; Altoè, G. The Strengths and difficulties questionnaire (SDQ). Early evidence of its reliability and validity in a community sample of Italian children. Pers. Individ. Dif. 2010, 49, 570-575.

47. Rønning, J.A.; Handegaard, B.H.; Sourander, A.; Mørch, W.-T. The strengths and difficulties self-report questionnaire as a screening instrument in Norwegian community samples. Eur. Child Adolesc. Psychiatry 2004, 13, 73-82.

48. Van Roy, B.; Grøholt, B.; Heyerdahl, S.; Clench-Aas, J. Self-reported strengths and difficulties in a large Norwegian population 10-19 years. Eur. Child Adolesc. Psychiatry 2006, 15, 189-198.

49. Van Widenfelt, B.M.; Goedhart, A.W.; Treffers, P.D.A.; Goodman, R. Dutch version of the Strengths and difficulties questionnaire (SDQ). Eur. Child Adolesc. Psychiatry 2003, 12, 281-289.

50. Yao, S.; Zhang, C.; Zhu, X.; Jing, X.; McWhinnie, C.M.; Abela, J.R.Z. Measuring adolescent psychopathology: Psychometric properties of the self-report strengths and difficulties questionnaire in a sample of Chinese adolescents. J. Adolesc. Health 2009, 45, 55-62.

51. Rajmil, L.; Palacio-Vieira, J.A.; Herdman, M.; López-Aguilà, S.; Villalonga-Olives, E.; Valderas, J.M.; Espallargues, M.; Alonso, J. Effect on health-related quality of life of changes in mental health in children and adolescents. Health Qual. Life Outcomes 2009, 7, 103.

52. Woerner, W.; Becker, A.; Rothenberger, A. Normative data and scale properties of the German parent SDQ. Eur. Child Adolesc. Psychiatry 2004, 13, ii3-ii10.

53. Ortuño-Sierra, J.; Fonseca-Pedrero, E.; Sastre i Riba, S.; Muñiz, J. Different patterns of behavioural and emotional difficulties through adolescence: The influence of prosocial skills. Ann. Psicol. 2016, 33, 48. [Green Version]

54. Ortuño-Sierra, J.; Fonseca-Pedrero, E.; Paíno, M.; Aritio-Solana, R. Prevalence of emotional and behavioral symptomatology in Spanish adolescents. Rev. Psiquiatr. y Salud Ment. 2014, 7, 121-130.

55. Prior, M.; Virasinghe, S.; Smart, D. Behavioural problems in Sri Lankan schoolchildren: Associations with socio-economic status, age, gender, academic progress, ethnicity and religion. Soc. Psychiatry Psychiatr. Epidemiol. 2005, 40, 654-662.

56. Ussher, M.H.; Owen, C.G.; Cook, D.G.; Whincup, P.H. The relationship between physical activity, sedentary behaviour and psychological wellbeing among adolescents. Soc. Psychiatry Psychiatr. Epidemiol. 2007, 42, 851-856.

57. Suchert, V.; Hanewinkel, R.; Isensee, B. Sedentary behavior and indicators of mental health in school-aged children and adolescents: A systematic review. Prev. Med. 2015, 76, 48-57.

58. Rodriguez-Hernandez, A.; Cruz-Sanchez Ede, L.; Feu, S.; Martinez-Santos, R. Inactivity, obesity and mental health in the Spanish population from 4 to 15 years of age. Rev. Esp. Salud Publica 2011, 85, 373-382.

59. Sanchez-Villegas, A.; Ara, I.; Guillén-Grima, F.; Bes-Rastrollo, M.; Varo-Cenarruzabeitia, J.J.; Martinez-González, M.A. Physical activity, sedentary index, and mental disorders in the sun cohort study. Med. Sci. Sports Exerc. 2008, 40, 827-834.

60. Plass-Christl, A.; Haller, A.-C.; Otto, C.; Barkmann, C.; Wiegand-Grefe, S.; Holling, H.; Schulte-Markwort, M.; Ravens-Sieberer, U.; Klasen, F. Parents with mental health problems and their children in a German population based sample: Results of the BELLA study. PLoS ONE 2017, 12, e0180410.

61. Wang, J.-J.; Smith, W.; Cumming, R.G.; Mitchell, P. Variables determining perceived global health ranks: Findings from a population-based study. Ann. Acad. Med. Singapore 2006, 35, 190-197.

62. Rajmil, L.; López-Aguilà, S.; Mompart Penina, A.; Medina Bustos, A.; Rodríguez Sanz, M.; Brugulat Guiteras, P. Socio-economic inequalities in children's mental health in Catalonia. An. Pediatría 2010, 73, 233-240.

63. Sonego, M.; Llácer, A.; Galán, I.; Simón, F. The influence of parental education on child mental health in Spain. Qual. Life Res. 2013, 22, 203-211.

64. Lapresa, L.B.; Arizaleta, L.H.; Rajmil, L. Social inequalities in mental health and health-related quality of life in children in Spain. Pediatrics 2012, 130, e528-e535.

65. Arroyo-Borrell, E.; Renart, G.; Saurina, C.; Saez, M. Influence maternal background has on children's mental health. Int. J. Equity Health 2017, 16, 63.

66. Davis, E.; Sawyer, M.G.; Lo, S.K.; Priest, N.; Wake, M. Socioeconomic risk factors for mental health problems in 4-5-year-old children: Australian population study. Acad. Pediatr. 2010, 10, 41-47.

67. Perna, L.; Bolte, G.; Mayrhofer, H.; Spies, G.; Mielck, A. The impact of the social environment on children's mental health in a prosperous city: An analysis with data from the city of Munich. BMC Public Health 2010, 10, 199.

68. Wlodarczyk, O.; Pawils, S.; Metzner, F.; Kriston, L.; Klasen, F.; Ravens-Sieberer, U. Risk and protective factors for mental health problems in preschool-aged children: Cross-sectional results of the BELLA preschool study. Child Adolesc. Psychiatry Ment. Health 2017, 11, 12.

69. National Statistics Institute. European Health Survey in Spain (EHSS); National Statistics Institute: Madrid, Spain, 2014; pp. 1-11.

70. Regidor, E. La clasificación de clase social de goldthorpe: Marco de referencia para la propuesta de medición de la clase social del grupo de trabajo de la sociedad Española de epidemiología. Rev. Española Salud Pública 2001, 71, 13-22.

71. Rajmil, L.; Siddiqi, A.; Taylor-Robinson, D.; Spencer, N. Understanding the impact of the economic crisis on child health: The case of Spain. Int. J. Equity Health 2015, 14, 95.

72. Klanšček, H.; Žiberna, J.; Korošec, A.; Zurc, J.; Albreht, T. Mental health inequalities in Slovenian 15-year-old adolescents explained by personal social position and family socioeconomic status. Int. J. Equity Health 2014, 13, 26.

73. Potijk, M.R.; de Winter, A.F.; Bos, A.F.; Kerstjens, J.M.; Reijneveld, S.A. Behavioural and emotional problems in moderately preterm children with low socioeconomic status: A population-based study. Eur. Child Adolesc. Psychiatry 2015, 24, 787-795.

74. Starfield, B.; Riley, A.W.; Witt, W.P.; Robertson, J. Social class gradients in health during adolescence. J. Epidemiol. Community Health 2002, 56, 354-361. [Green Version]

75. Maybery, D.; Reupert, A.; Goodyear, M.; Ritchie, R.; Brann, P. Investigating the strengths and difficulties of children from families with a parental mental illness. Aust. J. Adv. Mental Heal 2009, 8, 165-174.

76. Fong, V.C.; Hawes, D.; Allen, J.L. A systematic review of risk and protective factors for externalizing problems in children exposed to intimate partner violence. Trauma Violence Abuse 2017, 20, 149-167.

77. Bunston, W.; Franich-Ray, C.; Tatlow, S. A diagnosis of denial: How mental health classification systems have struggled to recognise family violence as a serious risk factor in the development of mental health issues for infants, children, adolescents and adults. Brain Sci. 2017, 7, 133.

78. Lila, M.; Gracia, E. Determinantes de la aceptación-rechazo parental. Psicothema 2005, 17, 107-111.

79. Alonso-Fernández, N.; Jiménez-García, R.; Alonso-Fernández, L.; Hernández-Barrera, V.; Palacios-Ceña, D. Mental health and quality of life among Spanish-born and immigrant children in years 2006 and 2012. J. Pediatr. Nurs. 2017, 36, 103-110.

80. León, B.; Felipe-Castaño, E.; Polo, M.I.; Fajardo-Bullón, F. Parental acceptance-rejection and profiles of victimization and aggression in bullying situations. Ann. Psicol. 2015, 31, 600-606.

81. Fajardo-Bullón, F.; Felipe-Castaño, E.; León-Del Baro, B.; MendoLázaro, S.; Polo Del Río, M.I.; Carroza, G. Harassment and mental health in Spanish children according to ENSE 2011. In Psicología y Educación: Presente y Futuro; Castejón Costa, J.L., Ed.; Asociación Científica de Psicologíay Educación: Aliciante, Spain, 2016; pp. 1630-1636.