Mental health problems are associated with a range of adverse outcomes as well as increased risk of later morbidity and premature mortality. Help seeking is uncommon at the early stages of mental health problems. Rather, treatment is often sought by patients after illnesses have already caused considerable distress or had substantial adverse personal, social and economic impacts. The purpose of the current work is to investigate the role of a number of early life course risk factors in the development of later psychopathology, using advanced statistical and epidemiological approaches applied to longitudinal data to ascertain predictive and causal pathways. The overall scope of this thesis is to provide the evidence necessary for developing primary and secondary prevention programs aimed at reducing the burden of mental illness on society.
Aim 1: To investigate the role of intrauterine growth restriction in increasing the risk of psychiatric disorders characterised by negative affectivity.
Aim 2: To investigate the potential for a transmission of maternal psychopathology to offspring.
Aim 3: To assess whether maternal prenatal infection and exposure to stressful life events predict positive psychotic experiences in the offspring directly, or indirectly via postnatal risks and antecedents of psychosis.
Aim 4: To investigate potential risk factors for the increased rates of female post-traumatic stress disorders, including gender-specific vulnerability resulting from physical assault and cognitive ability.
The data came from the Mater University Study of Pregnancy (MUSP), a prospective pre-birth cohort study which began in 1981 at the Mater Hospital in Brisbane, Australia. The baseline sample consisted of 7,223 pregnant women attending their first obstetric visit for that pregnancy. Since then follow-ups over 21 years have prospectively ascertained a range of health related data on both mother and child. The current work uses predictor variables and covariates from every measurement period, and behaviour and mental health measures ascertained from the offspring at ages 14 and 21 years. A number of statistical and methodological approaches were applied to estimate the longitudinal association between a number of early life course risk factors and later psychopathology, and to account for attrition.
The relationship between birth weight and later psychopathology was specific to particular psychiatric diagnoses, namely Post-Traumatic Stress Disorders, and comorbid Major Depression and Generalised Anxiety Disorders. The combination of maternal prenatal depressive, anxious and stress symptoms predicted increased internalising and externalising behaviour problems in adolescent and adult offspring. Prenatal maternal infections and stressful life events predicted later offspring psychotic experiences via the intermediaries of early infant illness susceptibility and child behaviour problems respectively. The risk of Post-Traumatic Stress Disorder associated with physical assault and lower cognitive ability was greater in females.
The current work contributes a number of substantive findings to the existing body of work related to early life course determinants of psychopathology, using sophisticated statistical techniques applied to epidemiological methods to clarify relationships, and strengthens evidence for preventive approaches to psychopathology.