SciELO - Scientific Electronic Library Online

 
vol.80 issue2  suppl.Language and learning disordersNeuropsychological assessment in children author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Jornal de Pediatria

Print version ISSN 0021-7557

J. Pediatr. (Rio J.) vol.80 no.2 suppl.0 Porto Alegre Apr. 2004

http://dx.doi.org/10.1590/S0021-75572004000300013 

REVIEW ARTICLE

 

Environmental influences on child mental health

 

 

Ricardo HalpernI; Amira C. M. FigueirasII

IPhD. Associate professor, Fundação Federal Faculdade Ciências Médicas de Porto Alegre and Universidade Luterana do Brasil. Specialist in Development and Behavior of Children and Adolescents, University of North Carolina at Chapel Hill
IIMSc. Assistant professor, Department of Mother-Child Care II, Universidade Federal do Pará (UFPA), Belém, PA, Brazil

Correspondence

 

 


ABSTRACT

OBJECTIVE: To present an up-to-date review about environmental influences on child mental health, describing major risk factors and discussing recommendations for intervention by pediatricians.
SOURCES OF DATA: MEDLINE, PsycLIT and Lilacs, technical books and publications about child development and child and adolescent mental health problems and health promotion.
SUMMARY OF THE FINDINGS: Children are exposed to multiple risk factors, among them high prevalence of disease, premature birth, being born from a problematic pregnancy, and living in poverty. This negative chain of events increases the risk for emotional problems. The negative effects on development and behavior result from the complex interaction between genetic, biological, psychological and environmental risk factors. The main factors influencing the mental health of children are the social and psychological environment. The cumulative risk effect is more important in determining emotional problems in children than the presence of one single stressor, regardless of its magnitude.
CONCLUSION: Environmental factors play an important role in the etiology of emotional problems in childhood. An adequate clinical investigation allows pediatricians to identify risk factors for the development of mental health problems and to ensure early intervention for children at risk.

Key words: Child mental health, risk factors, environment, child development, early intervention.


 

 

Introduction

Pediatricians have shown more interest in children's mental health in the last few years. This concern mirrors the fact that recent studies have found a prevalence of mental disorders of 10 to 20%, being considered the most important cause of childhood problems.1 According to a recent study, Glied & Cuellar estimate that 11% of U.S. children have a mental disorder of some sort.2 Half of the children and adolescents between ten and seventeen years old are affected at least by two risk behaviors, such as abuse of alcohol and drugs, delinquency, low school performance and pregnancy.3 Several studies from different countries have revealed an equally high percentage of preschool and school-aged children with emotional disorders.4-6

The improvement in pediatrics leads us to a substantial change of paradigm in terms of child and adolescent health care. With various therapeutic instruments at hand, pediatricians could divert their attention away from the treatment of acute diseases, based on the hospital-based model, and provide the population with community-centered health care. This way, by preventing diseases and promoting health, the coverage of this treatment could be extended. Synergistically, such measures further decreased infant mortality, revealing new problems, which were grouped under the name of "new morbidity" or "hidden morbidity,"7 defined in the 1970s as a set of functional situations and environmental factors that affect child development.8 The situations that resulted from the decrease in infant mortality submitted children, who were previously exposed to the risk of death, to the stress caused by unfavorable living conditions, most of which are the result of increased urbanization, violence, changes in family structure, and in some specific areas, the result of poor food supply.9 The group of children with this "new morbidity" includes those who experienced childhood abuse, maltreatment, neglect and developmental disabilities caused by lack of stimuli or inappropriate stimuli. The etiology of mental disorders in children often is attributed to these factors, but it is important to assess the multiple contexts in which these children live from birth to adolescence and adulthood. Most studies have focused on individual behavioral processes that determine mental health, leaving aside the fact that the continuity of adverse environmental factors also determines changes in child development.10 Mental disorders in childhood and adolescence have an immediate impact on children and their families and also are precursors of psychiatric and social problems throughout life.11,12 The present study discusses the influence of environment on children's mental health, the major risk factors involved, and some early interventions.

 

Environmental risk factors and mechanisms of action

Risk factor is defined as an element that determines an increased probability of problem occurrence. It can also be defined as a factor that increases vulnerability of a person or group to a certain disease or to health deterioration.13

According to Garbarino,14 we should bear in mind two types of interactions when we talk about risk: firstly, the interaction of children as a biological organism with their immediate social environment, represented by the family (microsystem), in which several processes, events and relationships occur; secondly, the interaction regarding the relationship of this system with the environment, in its broadest meaning (exosystem or macrosystem) through time (chronosystem). This model is shown in Figure 1, which describes the relations between several systems that influence children's lives, according to Bronfenbrenner's ecological theory of development.15 The author proposes a model where development occurs through processes of reciprocal interaction that are progressively more complex between children and all levels of environmental influences.

 

 

Children have different opportunities in their development given by their personal attributes (physical and mental) and by the social environment in which they live. As several studies have shown, direct threats to development may occur due to acquired genetic and biological problems, although this may also occur due to the absence of expected opportunities. In short, the forms though which the risk of developmental disorders appear may be related to biological substrate, to direct or indirect continuity of environmental interference and cognitive processes.16-21 Therefore, the negative effects on development are produced by the combination of genetic, biological, psychological and environmental risk factors, usually involving complex interactions between them. Social and psychological factors are strongly associated with children's mental health, influencing more than the individual's intrinsic characteristics.22-25

The several factors involved in the etiology of developmental and behavioral disorders rely more on the amount than on the nature of risk factors, since different risk factors produce similar results.26 Therefore, we reinforce the importance of multiple risks, whose cumulative effect proved to have a great impact on children's cognitive and socioemotional results.27,28

The Rochester Longitudinal Study, carried out by Sameroff et al., on the role of the environment in the determination of mental health followed up children from the prenatal period to adolescence.23 The main findings of this study regarding the influence of environmental factors on mental health were: a) history of maternal mental disease; b) high level of maternal anxiety; c) limited parental perspectives; d) poor interaction between children and their mothers; e) head of the family without qualified occupation; f) low maternal education; g) family of minority ethnic groups; h) single-parent families; i) presence of stressful events; j) families with four or more children. The multiple risk effect individually compared with each variable showed that high-risk children (e.g.: those with mental health problems in the family, parent's low expectation, poor mother/child interaction, low level of maternal education and no family support) had 24 times more chances of having a deficiency, compared to low-risk children. On top of that, the set of variables explained 50% more of the variation in verbal skills than did the variables that were individually assessed. Some of these findings were also obtained by other studies on development, although some of them applied different methodologies,28,29 which reinforces their importance. These findings emphasize the need to identify the group of children at higher risk for emotional and behavioral problems. A recent study carried out by Harland et al.30 showed a statistically significant association between familial characteristics and the risk of emotional and behavioral disorders in children, among which parental unemployment and recent separation from parents are the most important factors.

Several epidemiological studies demonstrated the relationship between low socioeconomic level and the occurrence of mental disorders in children.31-34 These findings are plausible given the higher probability for the existence of multiple risks in the underprivileged population. However, it is essential to distinguish between two important concepts that are strongly associated with the etiology of mental health: social causation and social selection.35 The first one refers to the interaction between genetic and environmental factors in which genetic aspects are latent until individuals exposed to adverse factors and stress (common in unfavorable socioeconomic situations) develop mental disease, due to situations that run out of their control. The second one refers to a correlation between genetic and environmental aspects where susceptible individuals are pushed down to the poverty line or cannot come out of it, causing the environment to increase the risk of mental disease. The distinction between these two theories is important, since it influences prevention and/or intervention strategies. In a recent study, Costello et al. found that coming out of the poverty line significantly decreased behavior-related symptoms (oppositional behavior and conduct disorder) in children, but that it did not change other psychiatric symptoms such as anxiety and depression, suggesting the existence of different mechanisms that are not directly related to unfavorable socioeconomic conditions.36

These are also the conclusions of one of the most important longitudinal studies on children's development and behavior, conducted by Werner et al.,37-42 which has followed up children since 1955 and revealed that most individuals exposed to birth-related biological problems do not develop any kind of adaptive difficulty in adolescence and adulthood. Perinatal complications, when analyzed individually, are not predictors of later physical and psychological developmental delays, but present an increased risk only if combined with adverse environmental situations.43,44 According to the two-year follow-up, wealthier children with perinatal complications had a mean IQ score five to seven points lower than wealthier children without perinatal complications. On the other hand, poorer children with perinatal problems had a decrease between 19 and 37 points in their IQ, comparatively to poorer children without perinatal problems.37 In the 18-year follow-up, the authors found out that adolescents with behavioral developmental problems lived in poverty at a percentage 10 times higher than those who had been exposed to perinatal problems.41 Lipman et al.,34 even without assessing biological risk, showed that children of low-income families have three times more chances of having a low school performance and social difficulties, compared to those of more privileged families. In addition, low maternal education and the existence of disruptive families had independent effects on the etiology of psychosocial morbidity.

Besides the importance of being aware of the risks to which these children are submitted, we should also consider a person's ability to adapt to certain types of stress. Anthony45 described the concept of "invulnerability" that certain children have to certain types of aggression. This adaptation has been called resiliency, which in physics, is the capacity of a material to return to its original shape or position after deformation that does not exceed its elastic limit. Applying this example to individuals, it means a person's ability to bounce back from potentially negative events. This resiliency, however, is not totally present in children, and thus the child may be highly efficient in dealing with a stressful situation at school, and extremely inefficient in dealing with a situation that involves emotions.46 Thus, living in poverty and in a psychologically unfavorable environment are high-risk conditions for physical and mental disorder, but certain individuals can develop competences for a good physical and mental development. These resilient people have personal attributes that act synergistically with the support received from the family and community.47

Nevertheless, the concept of resiliency runs counter to that of vulnerability, according to which certain children, for being exposed to the same stress, develop difficulties that interfere in their development and behavior. In the last few years, research about protective factors has changed in terms of methodology. While cross-sectional and retrospective studies have provided elements to define possible risk and protective factors,16 longitudinal and prospective studies have been used to document and analyze the short- and long-term effects of these factors on child's development and emotional functioning.42,48,49

 

Interventions for mental health promotion in childhood

The studies on the efficacy of early institutionalized intervention programs for the prevention of behavioral and/or learning disorders in children have yielded contradictory results regarding the general population. However, when studying populations with a low socioeconomic level, there seems to be an agreement on the benefits that these interventions provide, especially those that are maintained for a long period of time.50,51 The benefits of social and community services for the intervention are characterized by a decrease in intrafamily violence and social misdemeanors, and also cause a positive effect on the relationship between mothers and children. The larger impact occurs when interventions are initially made in the prenatal period and extend up to the first three years of life.52

One of the most important preventive measures that offers benefits in several areas is breastfeeding encouragement. Although no definitive conclusions exist as to the role of human milk in cognitive development, different studies conducted in different social contexts suggest that breastmilk has a positive effect on child development and on the mother/child relationship.53 If this relationship is sound, it is a good start for the child's mental health. In a cohort study carried out in Pelotas, southern Brazil, 1,363 newborn infants were followed up during their first year of life and the relationship between development and breastfeeding, among other variables, was assessed.28 The results showed a dose-response effect regarding the length of breastfeeding: the longer the breastfeeding period, the lower the risk of having a Denver II test with suspected delay. Non-breastfed children had an 88% greater risk of having a test with suspected delay, compared to those breastfed for longer than six months. In addition to proven nutritional, psychological and immunological advantages,54-56 the evidence that breastfed children have a better performance in their future cognitive development is another reason for breastfeeding to be encouraged consistently. Breastfeeding is not an innate behavior, but a habit that depends on learning and on the positive interaction between cultural and social factors.57,58

Intervention on the risk factors and mechanisms of action that influence children's mental health goes beyond the health sector. Joint actions that involve the health sector, education, social assistance, and economics are increasingly needed, producing jobs and income for the families, infrastructure and leisure. Integrated projects aimed at promoting children's and adolescents' good development have been implemented in different communities, especially in the ones with lower socioeconomic level, showing a high probability of success.59,60

Even though most developmental and behavioral disorders may be recognized still in childhood, disorders such as speech delay, hyperactivity and emotional disorders are not commonly diagnosed before the third or fourth years of life.61 In primary care, health professionals often do not assess children's development and mental health as a routine practice.62

The positive impact that early intervention programs have shown in terms of children's development and later school performance are a definitive justification for the necessity of early identification of children at risk for such delays.63-66

To be efficient, the programs should include the major groups of children at risk: a) group with an established diagnosis, for instance, syndromes in which delays are a natural part of the course of the disease, would have an intervention for the improvement of infants and/or children with growth and behavior retardation with established disabilities;67 with regard to the group of children at biological risk, usually related to pregnancy and/or birth conditions, as is the case of preterm babies, preventive interventions should be implemented for infants with increased biomedical risk;68 finally, the group of children who have social risks related to unfavorable socioeconomic conditions, poor family structure and inappropriate health care, the strategy includes preventive interventions for infants and children with increased environmental risk.69-71,30

It is quite difficult to distinguish the actual impact of social variables from the impact of biological variables, since the relationship between them is quite complex, thus hindering the interpretation of results and consequently the intervention.

There are biological and environmental components in the etiology of mental disorders that affect the neural substrate. Brain dysfunctions are not the only etiology of psychopathology, but also have an impact that depends on the individual's environmental and social response, thus determining the risk for a negative result. Environmental conditions such as no physical and social stimulus, poverty, stress, and prenatal exposure to drugs, may compromise brain functions in the presence of predisposing conditions.72 The relationship between genetics and environment is dynamic and also cumulative in its ability to influence development and change subsequent behaviors. This combination makes brain function malleable enough to reduce the risk of mental disorders by changing the environment. For instance, the neurobiology of processes related to social anxiety shows the clear relationship between neurochemical susceptibility, which combined with an unfavorable exposure, causes a disruption in brain homeostasis.73

Some theories exist on the neurobiology of drugs of abuse, suggesting that addiction is strongly associated with genetic mutations in neurotransmitters, making susceptible individuals abuse the substance in order to increase the levels of dopamine in their brain.74 An extensive review on this topic can be found in Gil-Verona et al.74 Research improvements in this area will allow a change in the course of development or at least attenuation of negative results.

According to Werner,40 risk factors are not static elements and are only valid if they are linked to intervention programs, where there is a regular follow-up, offering health education, rehabilitation and treatment.

Despite the fact that early interventions in developing countries may be more difficult, several alternatives exist that could promote low-cost and community-based programs, involving children at risk for mental disorders. The type of model depends on the target population. According to Thorburn,75 there are nine available models, ranging from home visits (on which occasion the mother is taught how to stimulate her child), day care center (as a training center for caregivers), and school, with teacher's participation and parental training, and participation of the media, as described in Table 1.

 

 

Problems associated with children's mental health are not restricted to specialists' private practices, but are very common in primary care. Academic researchers are often found in specialized university centers and have sufficient knowledge about the distribution of health problems in the community. On the other hand, they cannot observe treatment results and do not know much and are poorly interested in the interrelations of different types of health conditions in the use of services and in the subsequent effects of these services on health.76

In their turn, clinicians, especially those with a well-defined clientele, which is continually followed up for several years (such as pediatric clients), are exposed to the initial stages of the problem. They have a privileged position in making a general assessment of the child in order to observe the interrelations of different symptoms of poor mental health, and follow the natural history of the dysfunction as the child grows up and develops.

Therefore, pediatricians play a key role in the intervention of mental and developmental disorders, since they often are the major source of information for parents about the development of their children, in addition to being the professionals that can identify risky situations earlier.

The involvement of pediatricians in health promotion of children and adolescents will certainly bring immediate effects on suffering and will improve the quality of life, in the medium and long run, reducing school failure, abusive use of drugs, violence, crime rate, and development of psychiatric disorders in adulthood.

 

References

1. Stewart-Brown S. Research in relation to equity: extending the agenda. Pediatrics. 2003; 112(Pt 3):763-5.         [ Links ]

2. Glied S, Cuellar AE. Trends and issues in child and adolescent mental health. Health Aff (Millwood). 2003;22(5):39-50.         [ Links ]

3. Dryfoos JG. Adolescents at risk: a summation of work in the field: programs and policies. J Adolesc Health. 1991;12:630-37.        [ Links ]

4. Kasius MC, Ferdinand RF, Van den Berg H, Verhulst FC. Associations between different diagnostic approaches for child and adolescent psychopathology. J Child Psychol Psychiatry. 1997;38:625-32.        [ Links ]

5. Lui X, Kurita H, Guo G, Kiyake Y, Ze J, Cao H. Prevalence and risk factors of behavioral and emotional problems among Chinese children aged 6 through 11 years. J Am Acad Child Adolesc Psychiatry. 1999;38:708-15.        [ Links ]

6. Nikapota AD. Child psychiatry in developing countries. Br J Psychiatry. 1991;158:743- 51.        [ Links ]

7. Costello EJ, Edolbrock C, Costello AJ. Psychopathology in pediatric primary care: the new hidden morbidity. Pediatrics. 1988;82:415.        [ Links ]

8. Haggerty RJ. Expenditures for child health care. Pediatrics. 1975;55(2):160-1.        [ Links ]

9. Engle PL, Castle S, Menon P. Child development: vulnerability and resilience. Soc Sci Med. 1996;43(5):621-35.        [ Links ]

10. Sameroff JA. Environmental risk factors in infancy. Pediatrics. 1998;102(5):1287-92.        [ Links ]

11. Rutter M. Pathways from childhood to adult life. J Child Psychol Psychiatry. 1989;30(1):23-51.        [ Links ]

12. Rutter M. Connections between child and adult psychopathology. Eur Child Adolesc Psychiatry. 1996;5 Suppl 1:4-7.        [ Links ]

13. Grizenko N, Fisher C. Review of studies of risk and protective factors for psychopathology in children. Can J Psychiatry. 1992;37(10):711-21.        [ Links ]

14. Garbarino J. The human ecology of early risk. In: Meisels SJ, Shonkoff JP, editors. Handbook of early childhood intervention. Melbourne: Cambridge University Press; 1990. p. 78-96.        [ Links ]

15. Bronfenbrenner U. A ecologia do desenvolvimento humano: experimentos naturais e planejados. 1ªed. Porto Alegre: Editora Artes Médicas Sul Ltda.; 1996.        [ Links ]

16. Rutter M. Epidemiological approaches to developmental psychopathology. Arch Gen Psychiatry. 1988;45(5):486-95.        [ Links ]

17. Barglow P, Contreras J, Kavesh L, Vaughn BE. Developmental follow-up of 6-7 year old children of mothers employed during their infancies. Child Psychiatry Hum Dev. 1998;29(1):3-20.        [ Links ]

18. Chance GW, Harmsen E. Children are different: environmental contaminants and children's health. Can J Public Health. 1998:89 Suppl 1:9-13.        [ Links ]

19. Donovan EF, Ehrenkranz RA, Shankaran S, Stevenson DK, Wright LL, Younes N, et al. Outcomes of very low birth weight twins cared for in the National Institute of Child Health and Human Development Neonatal Research Network's intensive care units. Am J Obstet Gynecol. 1998;179(1):742-9.        [ Links ]

20. Hertzman C. The case for child development as a determinant of health. Can J Public Health. 1998:89 Suppl 1:14-21.        [ Links ]

21. Strauss RS, Dietz WH. Growth and development of term children born with low birth weight: effects of genetic and environmental factors . J Pediatr. 1998;133(1):67-72.        [ Links ]

22. Bukowski WM, Sippola LK. Diversity and the social mind: goals, constructs, culture, and development. Dev Psychol. 1998;34(4):742-6.         [ Links ]

23. Sameroff AJ, Seifer R, Barocas R, Zax M, Greenspan S. Intelligence quotient scores of 4-year-old children: social- environmental risk factors. Pediatrics. 1987;79(3):343-50.        [ Links ]

24. Barocas R, Seifer R, Sameroff AJ. Defining environmental risk: multiple dimensions of psychological vulnerability. Am J Community Psychol. 1985;13(4):433-47.        [ Links ]

25. Sameroff A. Models of development and developmental risk. In: Zeanah Jr CH. Handbook of infant mental health. New York: The Guilford Press; 1993. p. 120-42.        [ Links ]

36. Rae-Grant N, Thomas BH, Offord DR, Boyle MH. Risk, protective factors, and the prevalence of behavioral and emotional disorders in children and adolescents. J Am Acad Child Adolesc Psychiatry. 1989;28(2):262-8.        [ Links ]

27. Sanson A, Oberklaid F, Pedlow R, Prior M. Risk indicators: assessment of infancy predictors of pre-school behavioural maladjustment. J Child Psychol Psychiatry. 1991;32(4):609-26.        [ Links ]

28. Halpern R, Giugliani ERJ, Victora CG, Barros FC, Horta BL. Fatores de risco para suspeita de atraso no desenvolvimento neuropsicomotor aos 12 meses de vida. J Pediatr (Rio J). 2000;76:421-8.        [ Links ]

29. McLeod JD, Nonnemaker JM. Poverty and child emotional and behavioral problems: racial/ethnic differences in processes and effects. J Health Soc Behav. 2000;41:137-61.        [ Links ]

30. Harland P, Reijneveld SA, Brugman E, Verloove-Vanhorick SP, Verhulst FC. Family factors and life events as risk factors for behavioural and emotional problems in children. Eur Child Adolesc Psychiatry. 2002;11:176-84.        [ Links ]

31. Dodge KA, Pettit GS, Bates JE. Socialization mediators of the relation between socioeconomic status and child conduct problems. Child Dev. 1994;65:649-50.        [ Links ]

32. Friedman RJ, Chase-Lansdale PL. Chronic adversities. In: Rutter M, Taylor E, editors. Child and Adolescent Psychiatry. 4th ed. Oxford: Blackwell Scientific; 2002. p. 261-76.        [ Links ]

33. Wachs TD. Necessary but not sufficient: the respective roles of single and multiple influences on individual development. Washington, DC: American Psychological Association; 2000.        [ Links ]

34. Lipman EL, Offord DR, Boyle MH. Relation between economic disadvantage and psychosocial morbidity in children. CMAJ. 1994;151(4):431-7.        [ Links ]

35. Dohrenwend BP, Levav I, Shrout PE, Schwartz S, Naveh G, Link BG. Socioeconomic status and psychiatric disorders: the causation-selection issue. Science. 1992;255:946-52.        [ Links ]

36. Costello EJ, Compton NS, Keeler G, Angold A. Relationships between poverty and psychopathology. JAMA. 2003;290(15):2023-9.        [ Links ]

37. Werner EE, Simonian K, Bierman JM, French FE. Cumulative effect of perinatal complications and deprived environment on physical intellectual and social development of preschool children. Pediatrics. 1967;39(4):490-505.        [ Links ]

38. Werner EE, Smith RS, French FE, editors. Kauai's children come of age: a longitudinal study from the prenatal period to age ten. Honolulu: University of Hawaii Press; 1971.        [ Links ]

39. Werner EE. High-risk children in young adulthood: a longitudinal study from birth to 32 years. Am J Orthopsychiatry. 1989;59(1):72-81.        [ Links ]

40. Werner EE. In: Meisels SJ, Shonkoff JP editors. Handbook of early childhood intervention. Melborne, Australia: Cambridge University Press; 1990. p. 97-116.        [ Links ]

41. Werner EE. The children of Kauai: resiliency and recovery in adolescence and adulthood. J Adolesc Health. 1992;13(4):262-8.        [ Links ]

42. Werner EE. Overcoming the odds. J Dev Behav Pediatr. 1994;15(2):131-6.        [ Links ]

43. Werner EE. Vulnerable but invincible: high risk children from birth to adulthood. Eur Child Adolesc Psychiatry. 1996:5 Suppl 1:47-51.        [ Links ]

44. Werner EE. Vulnerable but invincible: high-risk children from birth to adulthood. Acta Paediatr. 1997:422 Suppl:103-5.        [ Links ]

45. Anthony EJ. The syndrome of the psychologically invulnerable child. In: Anthony EJ, Koupernik C, editors. The child and his family: children at psychiatric risk. NewYork: Wiley; 1974. p. 529-44.        [ Links ]

46. Célia S. Promoção da saúde e resiliência. In: Fichtner N, editor. Prevenção, diagnóstico e tratamento dos transtornos mentais da infância e da adolescência: um enfoque desenvolvimental. Porto Alegre: Editora Artes Médicas Sul, Ltda ; 1997. p. 21-25.        [ Links ]

47. Kotliarenco MA, Cáceres I, Fontecilla M. Estado de arte em resiliencia. Organização Panamericana de Saúde, Washington; 1997.        [ Links ]

48. Garmezy N. Stress, competence, and development: continuities in the study of schizophrenic adults, children vulnerable to psychopathology, and the search for stress-resistant children. Am J Orthopsychiatry. 1987;57(2):159-74.        [ Links ]

49. Chorpita BF, Barlow DH. The development of anxiety: the role of control in the early environment. Psychol Bull. 1998;124(1):3-21.        [ Links ]

50. Campbell FA, Ramey CT. Effects of early intervention on intellectual and academic achievement: a follow-up study of children from low-income families. Child Development 1994;65:684-98.        [ Links ]

51. Bennett FC, Guralnick MJ. Effectiveness of developmental intervention in the first five years of life. Pediatr Clin North Am. 1991;38:1513-28.        [ Links ]

52. Bedregal P, Margozzini P, Molina H. Revision sistemática sobre a eficácia de intervenciones para el desarollo biopsicosocial de la niñez. Santiago: Organização Panamericana de Saúde; 2002.        [ Links ]

53. Pollitt E, Kariger P. Breastfeeding and child development. Food Nutr Bull. 1996;17(4):401-18.         [ Links ]

54. Victora CG, Smith PG, Vaughan JP, Nobre LC, Lombardi C, Teixeira AM, et al. Evidence for protection by breast-feeding against infant deaths from infectious diseases in Brazil. Lancet. 1987;2 (8554):319.        [ Links ]

55. Giugliani E, Issler R, Kreutz G, Meneses C, Justo E, Kreutz V, et al. Breastfeeding pattern in a population with different levels of poverty in Southern Brazil. Acta Paediatr. 1996;85(12):1499-1500.        [ Links ]

56. Cesar JA, Victora CG, Barros FC, Santos IS, Flores JA. Impact of breast feeding on admission for pneumonia during postneonatal period in Brazil: nested case-control study. BMJ. 1999;318(7194):1316-20.        [ Links ]

57. van Esterik P. The cultural context of breastfeeding and breastfeeding policy. Food Nutr Bull. 1996;17(4):422-7.         [ Links ]

58. Barros FC, Victora CG, Vaughan JP. Breastfeeding and socioeconomic status in Southern Brazil. Acta Paediatr Scand. 1986;75(4):558-62.         [ Links ]

59. Organização das Nações Unidas pela Infância - UNICEF. Projeto Desenvolvimento Infantil em Santana do Aura - Belém/PA, 2003.         [ Links ]

60. Organização das Nações Unidas pela Infância - UNICEF. Projeto Belém Criança - Belém/PA, 2003.         [ Links ]

61. Palfrei JS, Singer JD, Walker DK, Butler JA. Early identification of children special needs: a study in five metropolitan communities. J Pediatr. 1987;111:651-9.        [ Links ]

62. Figueiras ACM. Avaliação das práticas e conhecimento de profissionais da atenção primária à saúde sobre vigilância do desenvolvimento infantil [dirrestação]. Belém (PA): Universidade Federal do Pará; 2002.        [ Links ]

63. Baydar N, Reid MJ, Webster-Stratton C. The role of mental health factors and program engagement in the effectiveness of a preventive parenting program for Head Start mothers. Child Dev. 2003;74(5):1433-53.        [ Links ]

64. Grantham-McGregor S, Schofield W, Powell C. Development of severely malnourished children who received psychosocial stimulation: six-year follow-up. Pediatrics. 1987;79(2):247-54.        [ Links ]

65. Cadman D, Chambers LW, Walter SD, Ferguson R, Johnston N, McNamee J. Evaluation of public health preschool child developmental screening: the process and outcomes of a community program. Am J Public Health. 1987;77(1):45-51.        [ Links ]

66. Glascoe FP. Developmental screening. In: Wolraich ML, editor. Disorders of development & learning: a practical guide to assessment and management. 2nd ed. St Louis: Mosby-Year Book, Inc.; 1996. p. 89-128.         [ Links ]

67. Jozwiak S, Goodman M, Lamm SH. Poor mental development in patients with tuberous sclerosis complex: clinical risk factors. Arch Neurol. 1998;55(3):379-84.        [ Links ]

68. Gregoire MC, Lefebvre F, Glorieux J. Health and developmental outcomes at 18 months in very preterm infants with bronchopulmonary dysplasia. Pediatrics. 1998;101(5):856-60.        [ Links ]

69. Rutter M. Poverty and child mental health: natural experiment and social causation. JAMA. 2003;290(15):2063-4.         [ Links ]

70. Guralnick MJ, Bennett FC. A framework for early intervention. In: Guralnick MJ, Bennett FC, editors. The effectiveness of early intervention for at-risk and handicapped children. Orlando: Academic Press; 1987. p. 3-29.        [ Links ]

71. Oberhelman RA, Guerrero ES, Fernandez ML, Silio M, Mercado D, Comiskey N, et al. Correlations between intestinal parasitosis, physical growth, and psychomotor development among infants and children from rural Nicaragua. Am J Trop Med Hyg. 1998;58(4):470-5.        [ Links ]

72. Fishbein D. The importance of neurobiological research to the prevention of psychopathology. Prev Sci. 2000;1(2):89-106.        [ Links ]

73. Marcin MS, Nemeroff CB. The neurobiology of social anxiety disorder: the relevance of fear and anxiety. Acta Psychiatr Scand. 2003:417 Suppl:51-64.         [ Links ]

74. Gil-Verona JA, Pastor JF, de Paz F, Barbosa M, et al. Neurobiology of addiction to drugs of abuse. Rev Neurol. 2003;36(4):361-5.        [ Links ]

75. Thorburn JM. Practical aspects of programme development: prevention and early intervention at the community level. In: Thorburn JM, Marfo J, editors. Practical approaches to childhood disability in developing countries: insights from experience and research. St John's: Project Seredec Memorial University of Nefoundland; 1990. p. 31-54.        [ Links ]

76. Starfield B. Childhood morbidity: comparisons, clusters and trends. Pediatrics. 1991;88(3):519-26.        [ Links ]

 

 

Correspondence to
Ricardo Halpern
Rua Sarmento Leite, 245
CEP 90050-170 - Porto Alegre, RS, Brazil
Phone: +55 (51) 3224.8822
E-mail:rhalpern@terra.com.br