Social Psychiatry and Psychiatric Epidemiology

, Volume 40, Issue 10, pp 769–777

Childhood adversities as risk factors for adult mental disorders

Results from the Health 2000 study

Authors

    • Dept. of Mental Health and Alcohol ResearchNational Public Health Institute (KTL)
    • Health and Social Services DivisionSTAKES (National Research and Development Centre for Welfare and Health)
  • Erkki Isometsä
    • Dept. of Mental Health and Alcohol ResearchNational Public Health Institute (KTL)
    • Dept. of PsychiatryUniversity of Helsinki
  • Hillevi Aro
    • Dept. of Mental Health and Alcohol ResearchNational Public Health Institute (KTL)
  • Laura Kestilä
    • Dept. of Health and Functional CapacityNational Public Health Institute
  • Juha Hämäläinen
    • Dept. of Mental Health and Alcohol ResearchNational Public Health Institute (KTL)
  • Juha Veijola
    • Dept. of PsychiatryUniversity of Oulu and Muurola Hospital, Hospital District of Lapland
  • Olli Kiviruusu
    • Dept. of Mental Health and Alcohol ResearchNational Public Health Institute (KTL)
  • Jouko Lönnqvist
    • Dept. of Mental Health and Alcohol ResearchNational Public Health Institute (KTL)
    • Dept. of PsychiatryUniversity of Helsinki
Original Paper

DOI: 10.1007/s00127-005-0950-x

Cite this article as:
Pirkola, S., Isometsä, E., Aro, H. et al. Soc Psychiat Epidemiol (2005) 40: 769. doi:10.1007/s00127-005-0950-x

Abstract

Background

The sex-specific role of stressful or traumatic childhood experiences and adverse circumstances in developing adulthood mental disorders is complex and still in need of comprehensive research.

Methods

Within the Health 2000 project in Finland, a representative sample of 4,076 subjects aged 30–64 years were investigated to examine associations between a set of retrospectively self-reported adverse environmental factors during childhood (0–16 years) and mental disorders diagnosed in the past 12 months by the Munich Composite International Diagnostic Interview.

Results

Of the 60% of adults reporting at least one childhood adversity, 17% had a current (past 12 months) mental disorder, compared to 10% of the non-reporters. A moderate dose–response relationship between the total number of adversities and current disorders was observed. Paternal mental health problems associated particularly strongly with male depressive disorders (OR 4.46), and maternal mental health problems with female depressive disorders (OR 3.20). Although seldom reported, maternal alcohol problems associated with alcohol use disorders in both sexes. Being bullied at school and childhood family discord predicted a variety of adulthood disorders in both sexes. All these four adversity items were more typical for depressive disorders with an earlier onset. Among females, more adversities were associated with mental disorders and their statistical significance was greater than among males.

Conclusions

There are marked sex differences and several diagnosis-related patterns in the associations between reported childhood experiences and environmental circumstances and adulthood mental disorders. The impact of adversities is probably composed of a wide range of factors from direct causal associations to complex, interacting environmental effects. Variations in the reported associations reflect the differing genetic and environmental transmission mechanisms of mental disorders.

Key words

mental disorderslife change eventsrisk factorsenvironmentalchildhood

Introduction

Numerous risk factors for mental disorders, particularly depressive disorders, have emerged from epidemiological research. Studies based on either selected or representative populations typically report age-, sex-, employment- and marital status-related sociodemographic characteristics, adverse life events and somatic illness [14] as risk factors for current mental disorders.

Parental depressive disorders, as well as other psychopathology, are known to raise the risk of mental disorders in offspring [57]. Depressive-, anxiety-, and substance use disorders are known to overlap as risk factors, and the role of both parents has been emphasized, particularly in cases of concordance of psychiatric disorders, as has chaotic family environment [79]. Childhood traumas and parental psychiatric history reportedly associate with adulthood current mood and anxiety disorders, and particularly with comorbidity of different disorders [2]. However, the effect of less traumatic, but possibly harmful childhood circumstances or environmental factors on the prevalence or variance of various mental disorders in adulthood is less well documented, although it has been studied and proposed to be stronger among females [10, 11]. Some researchers have stated that women tend to be more sensitive to the influence of childhood separation than men [7, 12, 13]. Reasons for these may be many, but different adolescent developmental pathways and joint effects of biological vulnerabilities and environmental factors most likely play a role [11, 14, 15]. Clustering of reported adversities reportedly plays a role in the onset or development of an adult psychiatric disorder, either in a dose–response relationship [16, 17] or in terms of certain events clustering in a typical manner [10].

The mechanisms of association between childhood environmental factors and other adversities and later psychiatric morbidity remain largely unclear, although both genetic and environmental factors as well as their interaction are known to play a role [1821]. Evidence for a causal link between temporally distant phenomena is extremely difficult to locate, due to methodological problems (e.g., multiple confounding factors). However, detailed data on the variety of previous adversities and their relation to different classes of mental disorders could clarify the nature of these associations and possibly suggest further studies on causality and the relative importance of genetic and environmental transmission mechanisms of mental disorders. For instance, the impact of childhood economic disadvantage or unemployment in the family, as well as family discord and parents' divorce, is probably complex, and simple causal (particularly genetic) effects are difficult to identify. On the other hand, certain individual, directly traumatic events like personal abuse or being bullied at school, or a serious medical illness in the family could theoretically have a more direct causal, but only partly genetic (vulnerability-related) component. Parental mental illnesses are known to carry a heightened risk of mental disorders for offspring, with complex environmental and genetic transmission mechanisms [9, 15, 22, 23].

In Health 2000, a nationwide representative study of the physical and mental health of the Finnish adult population, the prevalence of mental disorders along with their sociodemographic risk factors were studied [1]. In the present study, the aim was to investigate to what extent and how childhood adverse environmental factors or circumstances associate with adulthood mental disorders, and to explore possible differences between males and females in this regard. With a retrospective design, we expected to find that parental psychopathology, childhood family socioeconomic disadvantage, and personal adversities would be associated in a specific way with selected adulthood affective-, anxiety- and alcohol use disorders and their comorbidity. In addition, we expected that clustering of these reported adversities would have an impact. Therefore, we also tested whether the number of adversities would associate with current disorders and would show a more or less linear relationship between the frequency of adversities and the response in terms of mental disorders. By means of data on the onset of depressive disorders, we also tested if an earlier-onset type of depression would associate with parental psychopathology or other adversities, which would perhaps indicate a more severe, and possibly more genetically determined depressive phenotype.

Methods

The Health 2000 Study was a multidisciplinary epidemiological survey in mainland Finland involving a regionally stratified sampling frame composed of adults aged 30 years and over. The study was carried out in 2000–2001 and coordinated by the National Public Health Institute (KTL). Data were collected via home or telephone interviews and self-report questionnaires, followed by a clinical examination that included the structured mental health interview [Composite International Diagnostic Interview (CIDI)]. Project details and methodology have been published earlier [1]. The sampling and weighing procedure was designed to obtain a nationally representative sample of subjects from the general population, aged 30 years and over. The present study included subjects aged 30–64 years who had participated in the Munich Composite International Diagnostic Interview (M-CIDI) and previously answered a series of questions concerning childhood adversities (N=4,706). Subjects older than 64 years were excluded because of possible recall errors, a decision supported by the fact that prevalences of any mental disorders among these subjects were markedly low in this study sample [1, 24].

The M-CIDI interview

The computer-aided mental health interview was performed at the end of the comprehensive health examination. The interview was designed to determine, among other things, the 12-month prevalence of major depressive episodes and disorder, dysthymia, general anxiety disorder, panic disorder with or without agoraphobia, agoraphobia, social phobia, and alcohol abuse and dependence. The subjects were also asked to estimate the age of first onset of a depressive disorder, if such emerged.

The total number of reliably performed mental health interviews was 6,005, amounting to 75% of the original sample. Compared to participants in the CIDI interview, those who only attended the home interview were found to differ by somewhat higher scores in Beck Depression Inventory (BDI) and General Health Questionnaire (GHQ) symptom measures, by slightly older age, more frequent single marital status and lower education. This was reported and discussed in an earlier work [1].

Mental disorders and their comorbidity

The DSM-IV diagnoses found were grouped into categories of depressive-, anxiety- and alcohol use disorders. The depressive disorders category included diagnoses of major depressive disorder or dysthymia during the last 12 months. Anxiety disorders included diagnoses of panic disorder (with or without agoraphobia), generalized anxiety disorder, social phobia, and agoraphobia (without panic disorder). Subjects with alcohol use disorders were those who fulfilled the diagnostic criteria of alcohol dependence or alcohol abuse during the last 12 months. Between them, the diagnostic hierarchy was followed, as in several other similar studies [25]. Comorbidity was defined as having suffered from disorders in more than one category within the past 12 months.

Sociodemographic factors

Basic sociodemographic data—age, sex, marital status, and current employment status—were collected in the home interview. Persons living together were classified as cohabitants irrespective of their official marital status. Employment status was classified according to whether the subject was currently (1) full- or part-time employed, 2) unemployed or laid off, 3) retired, or 4) having other status.

Childhood environmental factors

The questionnaires given to the subjects during the initial home interview contained a series of questions about their childhood environment. The questionnaire was to be returned when entering the final health examination weeks later. The subjects were instructed to choose “no”, “yes”, or “cannot say” when asked the following:

“When you think about your growth years, i.e., before you were aged 16, ...;”
  1. 1.

    Did your family have long-term financial difficulties?

     
  2. 2.

    Were your father or mother often unemployed although they wanted to work?

     
  3. 3.

    Did your father or mother suffer from some serious disease or disability?

     
  4. 4.

    Did your father have alcohol problems?

     
  5. 5.

    Did your mother have alcohol problems?

     
  6. 6.

    Did your father have any mental health problem, e.g., schizophrenia, other psychosis, or depression?

     
  7. 7.

    Did your mother have any mental health problem, e.g., schizophrenia, other psychosis, or depression?

     
  8. 8.

    Were there any serious conflicts within your family?

     
  9. 9.

    Did your parents divorce?

     
  10. 10.

    Were you yourself seriously or chronically ill?

     
  11. 11.

    Were you bullied at school?

     
Only “yes” answers were coded positive for these questions.

The total number of reported adversities per subject was recorded from 0 to 11, in order to explore possible clustering.

Statistical methods

In statistical analysis, diagnostic categories and their correlates were first analyzed by basic bivariate analyses, including chi-square tests. Mann–Whitney U-test was used to determine if subjects with different disorders differed from those without the disorders in the number of reported adversities. Individual adversities were then tested in binomial logistic regression models by sex, to predict categories of adulthood mental disorders (unadjusted models/testing). To estimate the effect of the respondent's current sociodemographic factors, binomial logistic regression models predicting categories of mental disorders, with age, marital status, employment status, and the set of adversities as independent variables, were performed separately for males and females. Using these odds ratios (OR) for the background factors (adjusting for these factors), the adversities were then tested individually to obtain odds ratios comparable with the unadjusted ratios. Interactions between age groups and any adversity were tested for both sexes in order to explore whether the timespan between the recalled adversity and the diagnosed current disorder would correlate.

A backward stepwise procedure was chosen to perform a final multinomial logistic regression model, in which sex and childhood adversities (maternal problems with alcohol, paternal mental health problems, family discord, respondent's own serious or long-term illness, bullied at school) were the factors to remain and explain the mental disorder patterns and their comorbidity within a multicategorical outcome variable (pure alcohol use disorder, pure depressive disorder, pure anxiety disorder, comorbid alcohol use disorder, or comorbid anxiety and depressive disorder).

Results are presented in terms of ORs, together with 95% confidence intervals (95% CI). A weighting adjustment was used in the analyses to take into account the sampling design and non-participation (the details of the weighting procedures are to be published elsewhere). The STATA statistical package (version 8.0) and SPSS software (version 12.02.2) were used for the analysis.

Results

Altogether, 60% of the subjects reported at least one of the presented childhood adversities. The most frequently reported adversities were parental medical illness or injury (24%), financial difficulties (22%), family discord (18%), and paternal alcohol use problems (17%), whereas maternal alcohol use problems were reported in only 2% and paternal mental health problems in 3% (Table 1). The total number of reported adversities had an impact on current mental disorders: the greater the number, the more frequently the subjects were diagnosed with any of the disorders tested (Table 2). This was confirmed with the separate age- and sex-adjusted logistic models, in which the number of adversities as a continuous variable associated with depressive disorders (OR 1.30, 95% CI 1.22–1.39), anxiety disorders (OR 1.35, 95% CI 1.25–1.46) and alcohol use disorders (1.15, 95% CI 1.05–1.26).
Table 1

Prevalences (%) of DSM-IV disorders according to the Composite International Diagnostic Interview among males and females reporting different childhood adversities

N=4,076, age 30–64 years

Depressive disorders (%)

Anxiety disorders (%)

Alcohol use disorders (%)

Comorbid disorders (%)

Disorders, total (%) for both sexes

7.2

4.5

5.1

2.6

 

Males (5.5)

Females (9.2)

Males (3.9)

Females (5.0)

Males (8.6)

Females (1.8)

Males (2.8)

Females (2.5)

Adversities and their frequencies (%) reported by subjects

 Economical difficulties (22.1)

8.0c

13.0c

5.5

9.8c

11.0a

1.8

4.5b

4.9c

 Parental unemployment (6.5)

8.7

8.5

3.1

2.6

8.3

2.0

3.1

2.0

 Parental medical illness or injury (23.7)

7.0a

9.8

5.6a

6.2

7.3

2.1

3.9

3.0

 Paternal alcohol problems (16.9)

8.2a

10.3

4.9

7.9c

10.4

3.9c

4.3

3.9a

 Maternal alcohol problems (1.6)

8.2

16.4

8.7

7.2

25.3b

9.7c

8.5

5.4

 Paternal mental health problems (3.1)

18.5c

23.2c

5.2

12.5c

9.1

1.1

6.8

10.2c

 Maternal mental health problems (3.4)

10.8

23.1c

7.6

10.3a

7.5

5.2a

6.2

4.1

 Family discord (17.5)

11.8c

15.2c

7.0b

10.0c

11.0

4.0c

4.7a

6.0c

 Parental divorce (10.3)

4.9

13.9b

5.0

9.0c

12.0

3.5a

4.1

5.1b

 Serious or long-term illness (4.9)

8.5

16.0b

11.4c

11.7c

11.5

2.5

8.6c

7.5c

 Bullied at school (15.6)

11.2c

16.0c

9.1c

9.5c

10.0

1.8

5.7c

4.7

 Any adversity (59.6)

6.8c

11.3c

5.1c

6.7c

9.6

2.1

3.6b

3.4c

 No adversities

2.8

6.0

2.4

2.4

7.3

1.2

1.6

1.0

Chi-square test (continuity correction), adversity vs no adversity

ap≤0.05

bp≤0.01

cp≤0.005

Table 2

The frequencies and clustering of reported adversities and prevalence of current diagnosed mental disorders

Number of adversities

Frequency

Percent

Depressive disorders (%)a

Anxiety disorders (%)a

Alcohol use disorders (%)b

Comorbid disorders (%)a

Any diagnosis (%)a

0

1,989

42.4

4.5

2.4

4.5

1.3

10.0

1

1,164

24.7

6.7

4.3

5.6

2.7

13.6

2

729

15.5

8.8

5.3

4.4

2.4

15.5

3

398

8.4

11.7

8.2

4.5

5.1

19.1

4

227

4.8

11.9

7.5

8.1

5.8

22.1

5

126

2.7

12.4

10.0

9.4

4.6

28.4

6

49

1.0

24.5

12.2

8.1

12.4

30.3

7

14

0.3

40.9

21.0

16.5

21.0

56.4

8

6

0.1

16.6

31.9

19.1

16.6

47.7

9

3

0.0

 

34.4

  

34.4

11

1

0.0

     

Total

4,706

100.0

     

ap<0.001, Mann–Whitney U-test

bp<0.01, Mann–Whitney U-test

Of individual adversities, females more often reported paternal alcohol problems (19 vs 15%, χ2=10.06, df=1, p<0.01), maternal alcohol problems (2 vs 1%, χ2=8.12, df=1, p<0.01), and serious family discord (21 vs 15%, χ2=26.26, df=1, p<0.001), whereas males slightly more often reported parents' unemployment (7 vs 6%, χ2=4.40, df=1, p<0.05). No general trend was found in associations between age groups and reported adversities (data available on request). Overall, the youngest age group recalled financial difficulties, unemployment, parental medical illness, and adversities less often than older age groups, but recalled paternal and maternal alcohol and mental health problems, family discord, and divorce relatively more often.

The prevalences of specific DSM-IV disorders are presented in Table 1. Of the subjects reporting childhood adversities, 17% had a current mental disorder, compared to only 10% of those not reporting childhood adversities (χ2=33.57, df=1, p<0.001). Of the subjects with a depressive disorder, those reporting the age of onset before the age of 30 years were significantly more likely than others to recall paternal mental health problems (17 vs 7%, χ2=4.15, df=1, p<0.05), maternal mental health problems (14 vs 3%, χ2=8.21, df=1, p<0.01), maternal alcohol problems (6 vs 1%, χ2=3.79, df=1, p<0.05) and being bullied at school (39 vs 25%, χ2=4.53, df=1, p<0.05).

In the logistic model for males, financial difficulties at home and bullying at school associated with all specific mental disorders after adjustment (Table 3). Among females, maternal mental health problems, family discord, and parental divorce were associated with all specific mental disorders.
Table 3

Logistic models for both sexes, both unadjusted (adversities individually) and adjusted for basic sociodemographic variables (all variables entered)

(a) Males  

Depressive disorders

Anxiety disorders

Alcohol use disorders

Comorbid disorders

OR

95% CI

OR

95% CI

OR

95% CI

OR

95% CI

OR

95% CI

OR

95% CI

OR

95% CI

OR

Age (55–64 years as reference)

 30–44 years

  

2.37

1.08–5.18

  

3.67

1.33–10.16

  

1.45

0.82–2.58

  

4.57

 45–54 years

  

2.61

1.26–5.40

  

4.86

2.01–11.73

  

1.26

0.71–2.23

  

3.9

Marital status, married as reference

 Cohabiting

  

0.65

0.30–1.41

  

0.85

0.39–1.88

  

1.83

1.19–2.81

  

0.6

 Divorced or separated

  

2.45

1.45–4.13

  

1.86

1.00–3.47

  

2.5

1.54–4.04

  

3

 Widow

  

2.86

0.81–10.02

  

2.51

0.71–8.90

  

0.88

0.12–6.55

  

0

 Never married

  

1.58

0.91–2.74

  

1.51

0.82–2.78

  

1.67

1.04–2.68

  

1.51

Employment status, employed as reference

 Unemployed

  

2.73

1.51–4.95

  

4.63

2.59–8.29

  

2.8

1.70–4.60

  

4.25

 Retired

  

2.66

1.34–5.30

  

2.68

1.21–5.96

  

1.23

0.62–2.42

  

3.03

 Other

  

1.66

0.50–5.50

  

3.35

1.23–9.08

  

1.23

0.45–3.38

  

2.25

 

Unadjusted

Adjusted

Unadjusted

Adjusted

Unadjusted

Adjusted

Unadjusted

Adjusted

Adversities, entered individually

 Financial difficulties

1.87

1.26–2.78

1.82

1.19–2.79

1.6

1.02–2.5

1.56

0.97–2.51

1.45

1.03–2.05

1.44

1.01–2.06

1.91

1.11–3.30

1.85

 Parental unemployment

1.84

1.03–3.26

1.76

0.96–3.21

0.76

0.30–1.89

0.63

0.24–1.69

0.98

0.55–1.76

0.95

0.51–1.76

1.1

0.44–2.72

1

 Parental medical illness or inquiry

1.55

1.04–2.32

1.47

0.96–2.27

1.65

1.06–2.58

1.64

1.02–2.64

0.81

0.55–1.21

0.83

0.56–1.24

1.58

0.90–2.77

1.54

 Paternal problems with alcohol

1.84

1.11–3.04

1.63

0.96–2.79

1.32

0.75–2.31

0.99

0.54–1.82

1.34

0.87–2.07

1.18

0.75–1.86

1.72

0.90–3.32

1.2

 Maternal problems with alcohol

1.64

0.38–7.06

1.16

0.25–5.39

2.36

0.53–10.42

1.62

0.38–6.94

3.79

1.49–9.64

3.01

1.05–8.64

3.3

0.77–14.11

1.92

 Paternal mental health problems

4.46

2.36–8.53

4.13

2.01–8.48

1.33

0.40–4.47

1.14

0.337–3.97

1.08

0.41–2.88

1.07

0.42–2.72

2.61

0.88–7.70

2.12

 Maternal mental health problems

2.29

0.97–5.37

2.2

0.91–5.33

2.06

0.78–5.42

1.95

0.80–4.76

0.87

0.34–2.27

0.89

0.34–2.35

2.35

0.83–6.68

2.48

 Family discord

3.16

2.03–4.89

3.16

1.98–5.03

2.09

1.24–3.52

1.97

1.13–3.44

1.42

0.97–2.09

1.29

0.86–1.95

1.89

1.05–3.40

1.66

 Paternal divorce

0.95

0.51–1.78

0.86

0.45–1.68

1.33

0.69–2.54

1.14

0.57–2.30

1.58

1.02–2.46

1.42

0.89–2.32

1.87

0.78–3.16

1.28

 Serious or long-term illness

1.76

0.82–3.77

1.32

0.61–2.84

3.46

1.80–6.62

2.81

1.44–5.48

1.45

0.75–2.79

1.25

0.63–2.50

3.59

1.76–7.31

2.74

 Bullied school

2.96

2.01–4.37

2.42

1.61–3.62

3.29

2.13–5.08

2.58

1.63–4.08

1.26

0.84–1.88

1.12

0.74–1.68

2.58

1.60–4.17

1.83

(b) Females

Depressive disorders

Anxiety disorders

Alcohol use disorders

Comorbid disorders

OR

95% CI

OR

95% CI

OR

95% CI

OR

95% CI

OR

95% CI

OR

95% CI

OR

95% CI

OR

Age (55–64 years as reference)

 30–44 years

  

1.51

0.84–2.72

  

2.26

1.04–4.93

  

4.74

0.81–27.54

  

2.97

 45–54 years

  

1.37

0.76–2.49

  

2.5

1.17–5.37

  

2.26

0.44–15.99

  

3.14

Marital status, married as reference

 Cohabiting

  

1.06

0.64–1.74

  

1.02

0.56–1.88

  

2.29

0.99–5.30

  

1.52

 Divorced or separated

  

1.96

1.33–2.88

  

1.42

0.82–2.48

  

1.99

0.76–5.21

  

1.81

 Widow

  

3.09

1.50–6.37

  

0.7

0.15–3.38

  

3.42

0.35–33.14

  

0.77

 Never married

  

1.37

0.83–2.27

  

2.01

1.21–3.33

  

2.6

1.09–6.19

  

2.97

Employment status, employed as reference

 Unemployed

  

1.27

0.79–2.05

  

1.65

0.91–3.00

  

2.98

1.40–6.32

  

2.4

 Retired

  

1.35

0.69–2.62

  

2.6

1.26–5.38

  

0.59

0.07–5.00

  

3.21

 Other

  

1.01

0.54–1.90

  

1.58

0.72–3.46

  

1.96

0.71–5.36

  

2.53

 

Unadjusted

Adjusted

Unadjusted

Adjusted

Unadjusted

Adjusted

Unadjusted

Adjusted

Adversities, entered individually

 Financial difficulties

1.74

1.28–2.36

1.73

1.25–2.38

3

2.01–4.47

2.86

1.90–4.30

1.02

0.51–2.04

1.03

0.50–2.12

2.94

1.71–5.05

2.73

 Parental unemployment

0.91

0.51–1.64

0.89

0.49–1.63

0.5

0.19–1.33

0.45

0.16–1.25

1.16

0.36–3.77

1.15

0.36–3.66

0.78

0.25–2.49

0.7

 Parental medical illness or inquiry

1.09

0.77–1.55

1.08

0.76–1.55

1.34

0.89–2.02

1.32

0.88–1.97

1.3

0.67–2.52

1.57

0.81–3.04

1.26

0.69–2.30

1.26

 Paternal problems with alcohol

1.19

0.85–1.66

1.18

0.84–1.67

1.86

1.27–2.83

1.78

1.19–2.67

3.32

1.79–6.16

2.98

1.59–5.58

1.83

1.06–3.18

1.65

 Maternal problems with alcohol

2

0.95–4.22

 

0.88–3.75

1.48

0.53–4.14

1.23

0.43–3.54

6.91

2.68–17.81

4.58

1.64–12.82

2.29

0.69–7.55

1.74

 Paternal mental health problems

3.26

1.98–5.39

3.22

1.95–5.32

2.92

1.58–5.42

2.51

1.37–4.62

0.62

0.08–4.60

0.62

0.08–4.84

5.17

2.55–10.49

4.46

 Maternal mental health problems

3.2

1.94–5.27

3.16

1.91–5.23

2.27

1.13–4.55

1.93

0.95–3.90

3.33

1.30–8.48

2.8

1.09–7.20

1.71

0.65–4.47

1.3

 Family discord

2.16

1.58–2.94

2.07

1.51–2.846

2.95

2.01–4.35

2.71

1.83–4.01

3.52

1.89–6.56

2.85

1.49–5.43

3.89

2.29–6.61

3.33

 Paternal divorce

1.72

1.18–2.50

1.64

1.12–2.40

2.09

1.26–3.45

1.92

1.16–3.17

2.33

1.12–4.87

2.05

0.95–4.39

2.38

1.28–4.44

2.09

 Serious or long-term illness

1.99

1.22–3.26

1.79

1.08–2.99

2.73

1.54–4.86

2.37

1.33–4.20

1.46

0.44–4.88

1.36

0.40–4.65

3.63

1.78–7.40

3.03

 Bullied school

2.23

1.61–3.08

2.09

1.51–2.90

2.4

1.57–3.66

2.16

1.41–3.30

1.06

0.47–2.39

0.88

0.39–1.98

2.32

1.29–4.17

1.97

In the multinomial logistic regression model, significant findings were mostly convergent with the binomial models (Table 4). Comorbid alcohol use disorders were particularly strongly predicted by maternal alcohol problems (OR 5.79) and comorbid depressive- and anxiety disorders by serious or long-term illness (OR 3.95), family discord (OR 2.76), and paternal mental health problems (OR 2.58). Being bullied at school predicted all categories of mental disorders apart from pure alcohol use disorders.
Table 4

A sex-adjusted multinomial logistic regression modela for different diagnosis- and comorbidity patterns (no diagnosis as a reference)

 

Pure alcohol use disorder

Pure depressive disorder

Pure anxiety disorder

Comorbid alcohol use disorder

Comorbid depressive and anxiety disorder

OR

95% CI

OR

95% CI

OR

95% CI

OR

95% CI

OR

95% CI

Males

5.92

3.88–9.02

0.45

0.33–0.62

0.73

0.5–1.09

3.14

1.66–5.93

0.68

0.41–1.11

Maternal problems with alcohol

4.00

1.68–9.52

1.53

0.67–3.5

1.71

0.59–4.98

5.79

1.87–17.88

0.50

0.07–3.8

Paternal mental health problems

0.40

0.1–1.67

2.04

1.18–3.53

1.16

0.48–2.79

1.96

0.65–5.85

2.58

1.19–5.61

Family discord

1.60

1.05–2.43

1.79

1.3–2.47

2.06

1.34–3.18

2.02

1.05–3.91

2.76

1.65–4.63

Serious or long-term illness

1.19

0.57–2.5

1.02

0.55–1.89

1.51

0.74–3.09

1.86

0.71–4.92

3.95

2.07–7.53

Bullied at school

0.88

0.55–1.4

2.20

1.6–3.02

2.70

1.78–4.09

2.34

1.25–4.38

1.67

0.96–2.9

aA backwards stepwise procedure, where sex and all the adversities (financial difficulties, parental unemployment, parental medical illness or injury, paternal problems with alcohol, maternal problems with alcohol, paternal mental health problems, maternal mental health problems, family discord, parental divorce, serious or long-term illness, bullied at school) were entered at first

In terms of age and adversity interactions, the only statistically significant interaction occurred among males; the interaction of the 55- to 64-year age group with any childhood adversity had a negative association (p=0.014) with depressive disorders.

Discussion

In a nationally representative general population sample, we found strong associations between retrospectively self-reported childhood adversities and current (past 12 months) DSM-IV diagnoses of depressive-, anxiety-, and alcohol use disorders and their comorbidity. A slight clustering and a moderate dose–response relationship between the total number of adversities and current disorders was also observed. In separate analyses, several disorder- and adversity-specific associations were found. Mental health problems of either parent were particularly associated with current (12 months) depressive disorders of same-sex offspring, and mother's alcohol problems (although seldom reported) with DSM-IV alcohol use disorders in both sexes. An earlier onset of depressive disorders was associated with parental mental health and maternal alcohol problems, and being bullied at school. In adjusted multivariate logistic settings, some of the associations were less apparent, indicating an additional, perhaps moderating role of more recent sociodemographic factors. Certain associations retained their significance in different statistical settings, suggesting that childhood family discord, being bullied at school, parental mental health problems, and serious medical illness may have independent effects on the development of an adulthood mental disorder. Adversities probably exert influence over a relatively long period of childhood and adolescence. It seems reasonable to assume that individual, genetically determined (and sex-related) vulnerabilities moderate the final effect or impact of these circumstances [26, 27]. On the other hand, it may be that in the long run more recent circumstances or factors largely determine the prevalence of adulthood mental disorders.

Sex differences

As in previous research, parental mental health problems in our study appeared to raise the risk of adulthood mental and alcohol use disorders. Paternal mental health problems increased the likelihood of current depressive disorders in both sexes and, in addition, of anxiety disorders in females. Among females, maternal mental health problems associated with depressive- and alcohol use disorders, and paternal alcohol problems with current anxiety- and alcohol use disorders. Parental divorce associated with depressive, anxiety and alcohol use disorders (the latter only when unadjusted for sociodemographic factors) among females but not males. The sex differences could be gender-related as well as having a sex-related, genetic nature. The sex- or gender-specific transmission (either to same-sex or different-sex offspring) is certainly an interesting topic for further studies investigating gender roles, genetic factors, or complex models [15, 19, 23].

The effect of reported childhood adversities seemed to be somewhat stronger among females, as measured by the number of significant associations and their level of significance. The finding persisted after adjusting for the sociodemographic factors. In addition to possible sex-related differences in the recall process, sex differences probably also reflect a different role of specific childhood circumstances and parental relations in the development of adulthood mental disorders [14]. These findings also support the previous view of a stronger vulnerability of females to several stressful or traumatic events [11], but do not exclude the possibility that females are more psychologically minded and prone to attribute childhood factors as precipitants for adulthood states.

Specificity of the associations

Family discord seemed to be relatively associated non-specifically with most of the adulthood mental disorder patterns. This finding probably indicates both a tendency to recall such discord among subjects with mental disorders in general, as well as a true association of childhood family discord with these disorders.

The findings on parental mental disorders are convergent with the abundant literature on the impact of parental depressive disorder on the development of adulthood depressive and other mental disorders [7, 2830]. The fact that the significance of these associations was not affected by the logistic models adjusting for current sociodemographic factors tends to emphasize the fundamental role of this association, which is perhaps at least partly explained by genetic factors. The earlier onset of depressive disorders associated with parental mental and partly alcohol use problems may somewhat support this idea of a perhaps more genetically determined and severe form of these disorders.

On the other hand, no specific association between paternal alcohol problems and current alcohol use disorders among males was seen, which was unexpected on the basis of the concept of type II alcohol dependence. Interestingly, however, paternal alcohol problems had a slight but significant association with anxiety disorders among females.

According to the multinomial model, maternal alcohol problems associated with adulthood pure and comorbid alcohol use disorders. In the binomial models for the sexes, maternal alcohol problems associated with alcohol use disorders among both sexes, although adjusting for current sociodemographic factors slightly reduced the significance of this association. In this case, it is worth noting that maternal alcohol problems were relatively rare during the childhood of the subjects studied here: only 3.5% of them recalled this adversity. It is therefore possible that reported maternal alcohol problems have been in many cases prominent, comorbid with other psychopathology, and perhaps both psychosocially disrupting and genetically predisposing. For reasons unknown, but possibly related to alcohol culture issues, our finding is somewhat at variance to the report of Bijl et al. [31] from the NEMESIS study using methods similar to ours.

The impact of childhood socioeconomic circumstances is probably complex and confounded by several interactions between factors during follow-up. It is interesting that unemployment in the primary family did not seem to associate with psychiatric morbidity in adulthood—almost the contrary—but financial difficulties did. Something similar was noted with family discord and parental divorce: whereas discord associated with current mental disorders, divorce did so only for females. There may be several explanations. Parents' unemployment may be a major source of family discord and associate with current mental or alcohol use problems, but when uncomplicated it may also associate with better opportunities for a supportive family life. This, in turn, could compensate for any adverse effects on childhood development. However, family discord is likely to act as a stressor and may threaten the psychological development of the offspring. Divorce as a reasonable solution in many cases may partially compensate for this negative influence, explaining its smaller effect on psychiatric morbidity. The fact that a slight association was found between parents' divorce and current depressive and anxiety disorders among females, but not males, indicates a different long-term impact of divorce between the sexes [14].

Subjects of both sexes with current depressive and anxiety disorders recalled being bullied at school quite frequently. Such experiences may embody humiliating characteristics that seem to predispose individuals to episodes of major depression at least [20]. On the other hand, it cannot be excluded that premorbidly depressed subjects are more likely to be bullied at school than others [32]. In addition to financial difficulties, a serious or long-term illness associated specifically with comorbid depressive and anxiety disorders. A traumatic, relatively direct and causal mechanism could explain at least part of these associations.

Methodological considerations

In a retrospective design like this, considerable care is needed when interpreting the results. The possibility of “effort after meaning”-type of bias should caution against premature conclusions about causal relationships between childhood adversities and mental disorders in adulthood. It is most likely, and certainly worth considering, that subjects with existing mental disorders are more prone to recall childhood adversities in order to explain, or find meaning in, their current state. Moreover, the mental state itself may explain the tendency to recall negative events, e.g., those with depression may be more likely to report adverse childhood events than those without depression, due to their existing depressive state [33].

However, we do not believe that this can explain all the associations and variance between different adversities. In our opinion, a comprehensive, process-like data collection setting within a general health evaluation consisting of several sources of information (home interview, questionnaires and a health examination) is likely to have reduced the tendency for outcomes to be explained in this way, as the mental health questions were recorded at the end of the data collection (the final M-CIDI interview). The possibility of a recall bias regarding childhood adversities, being from a single data source, cannot be fully excluded though. However, even if there were tendencies to report past adversities because of present mental disorders, it remains most interesting and important that such associations differed markedly according to the current disorder and between the sexes. It is worth mentioning that the odds ratios found here were significantly high (>2 on average) and indicative of true associations, regardless of the existence or non-existence of any causal assumptions or conclusions.

Due to applied analysis design, numerous individual tests were performed on the same data, which may increase the chance of Type 1 errors. Therefore, some findings could have occurred by chance and should therefore be interpreted with caution.

We found no unambiguous evidence for a tendency to recall more or less adversities according to current age, but rather some probable cohort effects. Significant differences in associations between different adversities and disorder categories suggest further studies on possible mechanisms for these associations, irrespective of whether certain adversities raise the risk of certain mental disorders or certain disorders enhance the recall of certain childhood factors.

The lack of marked age–adversity interactions decreases the possibility of systematic age-related recall bias. It has been suggested that the recall of adversities would be relatively frequent among younger subjects overall [28], but we found no support for this. There was, however, marked variation in the associations between age groups and different adversities, and they indicated no obvious trend. This probably reflects generational or cohort differences in the prevalence of certain events and, on the other hand, varying tendencies to recall or forget. Less frequent recall of financial disadvantage and more frequent reporting of parental alcohol use and mental health problems, family discord and divorce by younger age groups perhaps support the notion of a cohort effect. It was particularly interesting that most of this variation diminished in size and lost its statistical significance (only partly due to smaller sample sizes) when analyzed solely for subjects with diagnosed mental disorders. Finally, and from the overall methodological perspective, it is worth mentioning that our study used a large, nationwide, unselected sample, which, despite precluding detailed examinations of individual cases, certainly offers representative findings.

Conclusions

There are remarkable sex differences and diagnosis-related patterns of associations between reported childhood experiences and environmental circumstances and currently diagnosed mental disorders in adulthood. The effect of parental mental disorders may include both genetic and environmental factors. The impact of childhood financial difficulties or family discord is probably complex, whereas for instance being bullied at school or having a serious or long-term illness may exert a more direct effect. Variations in these associations suggest the need for further study, even though they partly reflected a tendency to recall certain adversities in efforts to explain or understand a current state or trait. The reported findings would seem to indicate both genetic and environmental transmission mechanisms of the most common mental disorders, although it was not possible to study this directly in the present setting.

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© Springer-Verlag 2005