Time trends in family risks and their impact Stephan Collishaw & Barbara Maughan MRC SGDP Centre Institute of Psychiatry Kings College London

Time trends in family risks and their impact


Stephan Collishaw & Barbara MaughanStephan Collishaw & Barbara Maughan

MRC SGDP CentreMRC SGDP CentreInstitute of Psychiatry King’s College LondonInstitute of Psychiatry King’s College London

Time trends in family risksTime trends in family risks

Recent decadesRecent decades• Marked changes in family demographicsMarked changes in family demographics

– age at marriage / cohabitationage at marriage / cohabitation– age at birth of first childage at birth of first child– family sizefamily size– partnership stability / breakdown partnership stability / breakdown – complexity of family formscomplexity of family forms

• Increases in psychosocial disorders among Increases in psychosocial disorders among young peopleyoung people

Time trends in adolescent conduct problemsTime trends in adolescent conduct problems 1974-19991974-1999

0

2

4

6

8

10

12

14

16

18

% h

igh

sco

res

1974 1986 1999

Boys

Girls

Collishaw et al, 2004

QuestionsQuestions• do changing family patterns ‘explain’ trends in do changing family patterns ‘explain’ trends in

child outcomes?child outcomes?

• do the same risk factors contribute todo the same risk factors contribute to

– individual differencesindividual differences in behaviour problems?in behaviour problems?

– overall overall levelslevels of behaviour problems?of behaviour problems?

• does thedoes the impactimpact of family risks change when of family risks change when

their prevalence changes?their prevalence changes?

0

2

4

6

8

10

12

14

16

1961 1966 1971 1976 1981 1986 1991 1993 1996 1999

ONS Population Trends 102, 2000 &Social Trends 20, 1990

Divorce rate per 1,000 married population

1961-1999 (England & Wales) Divorce rate per 1,000 married population

1961-1999 (England & Wales)

HypothesisHypothesis• increasing prevalence of divorce associated increasing prevalence of divorce associated

with with reductionreduction in impact in impact– pre-divorce ‘selection’ effectspre-divorce ‘selection’ effects

• less troubled familiesless troubled families• less parental discordless parental discord

– post-divorce consequencespost-divorce consequences• less social stigmaless social stigma• increased awareness of impact for childrenincreased awareness of impact for children

Parental divorce and child outcomesmeta analysis (Amato, 2001)

0

0.1

0.2

0.3

Me

an

eff

ec

t s

ize

Academic Conduct Self-concept

1950-1979 1980-1989Decade of publication

Parental divorce and child outcomesmeta analysis (Amato, 2001)

0

0.1

0.2

0.3

Me

an

eff

ec

t s

ize

Academic Conduct Self-concept

1950-1979 1980-1989 1990-1999Decade of publication

UK CohortsEly et al, 1999; Sigle-Rushton et al, 2005

0

0.5

1

1.5

2

OR / RR

Education Adult Malaise

1946 1958 1970Cohort

Possible explanationsPossible explanations• change in nature of marital dissolutionchange in nature of marital dissolution

– ‘‘low discord’ divorce especially distressing for low discord’ divorce especially distressing for childrenchildren

• increasing gap in economic well-beingincreasing gap in economic well-being– single-parent families not benefited from economic single-parent families not benefited from economic

expansionexpansion

AimsAims• update picture to include more recent cohortupdate picture to include more recent cohort• examine 3 family indicatorsexamine 3 family indicators

– family typefamily type– family incomefamily income– family sizefamily size

• explore changes in prevalence and impactexplore changes in prevalence and impact• illustrate changes in correlatesillustrate changes in correlates• test how far changing family risks ‘account for’ test how far changing family risks ‘account for’

rising levels of conduct problemsrising levels of conduct problems

Samples

C o h o r t 1

C o h o r t 2

C o h o r t 3

S t u d y N a t i o n a l C h i l d D e v e l o p m e n t S t u d y ( N C D S )

1 9 7 0 B r i t i s h C o h o r t S t u d y ( B C S 7 0 )

O N S C h i l d M e n t a l H e a l t h S u r v e y

D e s i g n L o n g i t u d i n a l

L o n g i t u d i n a l

C r o s s - s e c t i o n a l

P a r e n t r a t i n g s

R u t t e r A R u t t e r A G o o d m a n S D Q

N A g e 1 6

1 0 , 4 9 9 1 9 7 4

7 , 2 9 3 1 9 8 6

8 6 8 1 9 9 9

Age 16

• Family-based correlates– Family type (single vs. step vs. intact)

– Family income (<60% median vs. remainder)

– Family size (4+ children vs. 1-3 children)

• Adolescent conduct problems– fighting

– bullying

– stealing

– lying

– disobedience

Measures

0

2

4

6

8

10

12

14

16

1961 1966 1971 1976 1981 1986 1991 1993 1996 1999

ONS Population Trends 102, 2000 &Social Trends 20, 1990

Cohort 1

Cohort 2

Cohort 3

Divorce rate per 1,000 married population

1961-1999 (England & Wales) Divorce rate per 1,000 married population

1961-1999 (England & Wales)

Teenagers living with both birth parents

0

10

20

30

40

50

60

70

80

90

%

1974 1986 1999

Teenagers living in a step-family

0

5

10

15

20

%

1974 1986 1999

Teenagers living in single-parent households

0

5

10

15

20

25

30

%

1974 1986 1999

Low income by cohort: intact families

0

5

10

15

20

25

%

1974 1986 1999

Proportion of families in poverty: Single parent vs. intact families

01020304050607080

%

1974 1986 1999

SingleIntact

Increasing income-inequality: single parent vs. intact families

01020304050607080

%

1974 1986 1999

OR = 8.5

SingleIntact


01020304050607080

%

1974 1986 1999

OR = 8.5 OR = 10.1

SingleIntact


01020304050607080

%

1974 1986 1999

OR = 8.5 OR = 10.1 OR = 19.4

SingleIntact

Family type and conduct problems by cohort

0

2468

101214161820

% c

on

du

ct p

rob

lem

s

1974 1986 1999

Intact

Single parent

Family typeOR = 1.9


0

2468

101214161820

% c

on

du

ct p

rob

lem

s

1974 1986 1999

Intact

Single parent

Family typeOR = 1.9

OR = 2.1


0

2468

101214161820

% c

on

du

ct p

rob

lem

s

1974 1986 1999

Intact

Single parent

Family typeOR = 1.9

OR = 2.1

OR = 1.8


0

2468

101214161820

% c

on

du

ct p

rob

lem

s

1974 1986 1999

Intact

Step family

Family type

OR = 2.7


0

2468

101214161820

% c

on

du

ct p

rob

lem

s

1974 1986 1999

Intact

Step family

Family type

OR = 2.7OR = 2.2


0

2468

101214161820

% c

on

du

ct p

rob

lem

s

1974 1986 1999

Intact

Step family

Family type

OR = 2.7OR = 2.2

OR = 1.6

Summary: family type

Risk factor Exposure ‘Impact’

Single parent family Up No change

Step family Up Down?

50

75

100

125

150

175

200

225

250

1974 1986 1999

aver

age

inco

me

(100

= 1

970

leve

l)

Social Trends, 2002

Absolute household disposable income in the UK

(1974-1999)

Absolute household disposable income in the UK

(1974-1999)

0

5

10

15

20

25

30

1974 1986 1999

< 6

0% m

edia

n i

nco

me

Children All households

Social Trends, 2006

“Relative poverty” in the UK (1974-1999) “Relative poverty” in the UK (1974-1999)

0

5

10

15

20

25

30

1974 1986 1999

< 6

0% m

edia

n i

nco

me

“Relative poverty” by study cohort “Relative poverty” by study cohort

‘Relative poverty’ and conduct problems by cohort

0

5

10

15

20

25

% c

on

du

ct p

rob

lem

s

1974 1986 1999

no

yes

Low incomeOR = 1.4


0

5

10

15

20

25

% c

on

du

ct p

rob

lem

s

1974 1986 1999

no

yes

Low incomeOR = 1.4

OR = 2.1


0

5

10

15

20

25

% c

on

du

ct p

rob

lem

s

1974 1986 1999

no

yes

Low incomeOR = 1.4

OR = 2.1

OR = 1.7

Family size by cohort: % four or more children

0

5

10

15

20

25

30

%

1974 1986 1999

Family size and conduct problems by cohort

0

5

10

15

20

25

% c

on

du

ct p

rob

lem

s

1974 1986 1999

0-3

4+

N childrenOR = 3.0


0

5

10

15

20

25

% c

on

du

ct p

rob

lem

s

1974 1986 1999

0-3

4+

N childrenOR = 3.0

OR = 2.3


0

5

10

15

20

25

% c

on

du

ct p

rob

lem

s

1974 1986 1999

0-3

4+

N childrenOR = 3.0

OR = 2.3

OR = 1.8

Summary of findings up to now

Risk factor Exposure ‘Impact’

Single parent family Up No change

Step family Up Down?

‘Relative poverty’ No change Up

Large family size Down Down

Conduct problems: high scores

0

2

4

6

8

10

12

14

16

18

% h

igh

sco

res

1974 1986 1999

Boys

Girls

Total OR = 1.56 per cohort

What contributes to time trends in conduct problems?

1

1.2

1.4

1.6

1.8

2

Base model Family type and lowincome

Od

ds

rati

o


1

1.2

1.4

1.6

1.8

2

Base model Family type and lowincome

Od

ds

rati

o


1

1.2

1.4

1.6

1.8

2

Base model Family type andlow income

All predictors

Od

ds

rati

o


1

1.2

1.4

1.6

1.8

2

Base model Family type andlow income

All predictors

Od

ds

rati

o

Some conclusions

• 1. Parallel trends in risks and outcomes do not imply a causal link

– Increase in divorce rate over the past 30 years– Increase in conduct problems over the same time period– However, trends in family type appear largely

independent of trends in conduct problems

Some conclusions

• 2. Correlates of risk factors may change over time

– E.g. Amato– Only had limited data with which to look at this– Socio-economic disadvantage even more strongly

associated with single parenthood in more recent cohorts

Some conclusions

• 3. Implication: changes in impact of a risk factor as important as changes in exposure

– Focus on changes in exposure insufficient– Also need to consider possible change in association

between risk and outcome

– E.g. 1: family type and conduct problems; impact the same or reduced over time

– E.g. 2: relative poverty and conduct problems; impact gone

up over time

Some conclusions.

• 4. Different explanatory models needed for understanding individual differences and level differences

– Family type, income and size all associated with CP at individual level

– But, trends in these aspects of family life only made modest contribution to understanding of level differences

– Different factors may be relevant for the two



Stephan Collishaw & Barbara MaughanStephan Collishaw & Barbara Maughan

MRC SGDP CentreMRC SGDP CentreInstitute of Psychiatry King’s College LondonInstitute of Psychiatry King’s College London

Prevalence and odds of low income by family type and cohort

0

10

20

30

40

50

60

70

%

Traditional Single Step

1974

1986

1999

8.5 10.1 19.4

1.6 2.2 1.6

OR =

OR =

Documents

Time trends in family risks and their impact Stephan Collishaw & Barbara Maughan MRC SGDP Centre Institute of Psychiatry Kings College London