Abstract
Aims: This thesis sought to advance what is known about (i) the assessment of psychiatric family history, and (ii) the contribution family history can make to the UNDERSTANDING of longitudinal psychiatric phenotypes.
Methods: Family history of major depressive episode (MDE), anxiety disorder, schizophrenia, alcohol dependence, drug dependence, suicide attempt and conduct disorder/antisocial personality disorder (CD/ASPD), was assessed using the Family History Screen (FHS) for 981 members (51% male) of a longitudinal birth cohort.
Results" The FHS was shown to have acceptable levels of sensitivity and specificity (i.e., in line with other commonly used instruments). A number of informant characteristics (age, sex, disorder status) were found to bias family history reports. All disorders showed evidence of familiality. Family history scores that took account of 'density' (i.e., the number of disordered family members) predicted disorder outcomes better than scores that did not. Family history scores that took account of family size predicted disorder outcomes better than scores that did not only for disorders with a high population prevalence. Family history was associated with greater recurrence, worse impairment and greater service use for MDE, anxiety disorder, alcohol dependence and drug dependence (though not significantly for all disorders). Family history was not associated with age of onset for any disorder. Family history of externalising problems characterised boys on the lifecourse- persistent developmental pathway of CD/ASPD, but not boys on the childhood-limited or adolescent-onset pathways.
Conclusions: It is concluded that psychiatric family history data can he collected with adequate validity for clinical and research purposes. Moreover, across a number of disorders, family history is prognostic of later disorder outcomes. Thus, despite the advent of new technologies enabling genetic data to be collected quickly and inexpensively, our understanding of psychiatric illness is likely to continue to benefit from the use of the family history method.