Researcher Perspective Talk:

Modelling developmental processes

Vaso TotsikaCEDAR

Intellectual Disability and Autism

• Intellectual disability: below average cognitive skills (coupled with significant limitations in adaptive skills)

• Present in about 3% of the population

• Autism: neurodevelopmental disorder. Problems in social interaction, patterns of communication, and a repetitive repertoire of interests and behaviours

• Present in about 1% of the population

• Why SEM?

What I/we knew so far….

• 10s of studies: children with autism have higher levels of behaviour problems than typically developing children

• 10s of studies: increased stress levels in mothers of children with autism

• The two must be related (?)

Yes, they are

• 10s of studies suggesting child behaviour problems a systematic ‘predictor’ of parental well-being

• Evidence suggested that child CB a significant ‘predictor’ of parental well-being even after accounting for child ability/severity of ASD.

• Evidence suggested that after controlling for child CB, parental well-being no longer different from parents of TD children

Cross-sectional…

Longitudinal studies

T1-T2 Change in par. stress

Child CB T2

Child CB T1

Parent Stress T1

T1-T2 Change in child CB

Parent Stress T2

Parent Stress T1

Child CB T1

Multiple Regression Model 1 Multiple Regression Model 2

• If R2 for step 2 increased and betas for other person’s variables p<.05: significant• If significant in both models: evidence of bidirectional relationship

What is a bidirectional relationship?

Developmental theory -How best to describe the relationship between children and parents? Children and parents are dynamic entities

- What are the processes that explain development? Children and their environments are in a state of constant

interplay, shaping one another all the time (transactional relationship –Sameroff’s work)

---- How can this be modelled??

Transactional model

Sameroff, 2009, p.13

Makes sense now…

Structural equation model, path model, cross-lagged panel study, cross-lagged path analysis

Structural Equation Models

• Statistical methodology• Main function: to confirm a theory.• Can model a number of relationships (structural

equations) simultaneously.• Structural relationships can be modelled pictorially

(very useful for longitudinal data).• Allows for observed variables but also latent factors• Not so well developed (yet) for non-interval-level

outcomes

Totsika et al., 2013

Conclusion

• Findings did not support the presence of a bidirectional relationship.

• Child behaviour had a near-zero effect on maternal well-being across all models.

• Maternal psychological distress was associated with an increase in child behaviour problems 2 years later

• Maternal life satisfaction was associated with decreased child behaviour problems 2 years later

• So, is maternal well-being a risk factor for child behaviour?

Identifying Risk

• Not an analysis issue• A conceptual issue that (should) affects the

design of studies that want to identify risk factors

• To establish that a factor is a risk factor for an adverse outcome:

(a) It has to precede the outcome (b) It has to be correlated to the outcome

Totsika et al., in press

How do risk factors work together?

• Independent risk factors• Mediators• Moderators• Proxy risk factorsAll risk factors. Three things are important in helping us determine their relationship: a. Temporal precedence, b. correlation, c. dominance

Kraemer et al., 2001; Kraemer 2010

• Systematic definition of risk• Framework applied when (a) established risk factors

but unknown relationship (e.g., predicting re-offence (Lofthouse et al., in press), (b) selecting variables for confirming a hypothesised relationship

Kraemer et al., 2001

Back to development

• (My) world is full of risk and moderators!• SEP is a risk factor for child behaviour• SEP is a risk factor for mat depression• SEP moderates child CB- mat. well-being r• Coping moderates child CB- mat. well-being r• Social support moderates child CB- mat. well-being r• Social support is a protective factor for mat. Depression• Poor parenting a risk factor for child behaviour

• Interaction terms in Regression /ANOVA p<.05= Moderator!

• Moderators are sig. interactions but not all interactions are significant moderators.

Back to theory

SEPParent

emotional probs

Child well-beingParenting

Conger & Donellan, 2007

T 1 T 2 T 4T 3

SEPParent

emotional probs

Child well-beingParenting

T 1 T 2 T 4T 3

Par. investment

?

?

SEM

• A very useful technique for describing developmental processes / longitudinal relationships

• Modelling many regressions at once approximates better real-life than a series of regression models

• Pictorial + many time points: helpful in understanding/test risk relationships

Thank you

V.Totsika@warwick.ac.uk

• Conger, R.D., & Donellan, M.B. (2007). An interactionist perspective on the socioeconomic context of human development. Annual Review of Psychology, 58, 175-199.

• Kraemer, H.C. (2010). Epidemiological methods: About time. International Journal of Environmental Research and Public Health, 7, 29-45.

• Kraemer, H.C., Stice, E., Kazdin, A., & Kupfer, D. (2001). How do risk factors work together to produce an outcome? Mediators, moderators, independent, overlapping and proxy risk factors. American Journal of Psychiatry, 258, 848-856.

• Lofthouse, R., Totsika, V., Hastings, R.P., Lindsay, W.R., Hogue, T.E., & Taylor, J.L. (2014). How do static and dynamic risk factors work together to predict violent behaviour amongst offenders with an intellectual disability? Journal of Intellectual Disability Research, 58,125-133.

• Totsika, V., Hastings, R.P., Vagenas, D., & Emerson, E. (in press). Parenting and the behaviour problems of young children with an intellectual disability: Concurrent and longitudinal relationships in a population-based study. American Journal on Intellectual and Developmental Disabilities.

• Totsika, V., Hastings, R.P., Emerson, E., Lancaster, G.A., Berridge, D.M., & Vagenas, D. (2013). Is there a bidirectional relationship between maternal well-being and child problem behaviors in autism spectrum disorders? Longitudinal analysis of a population-defined sample of young children. Autism Research, 6(3), 201-211.