The results emphasize the importance of psychosocial risk factors for postnatal depression and suggest that most obstetric factors during pregnancy and birth do not significantly increase risk for this depression. Early identification of potential risk for postnatal depression should include assessment of sociodemography, personality, psychiatric history and recent life events, as well as past and present obstetric factors.

Neurotic syndromes are defined by characteristic patterns of symptoms, but the validity of the distinction between one syndrome and another depends on associations between the syndromes and clinical history, or treatment response factors that are independent of the defining phenomena. In both a group of twin volunteers and a group of patients with panic disorder/agoraphobia, the lifetime experience of more than one diagnosis of a neurotic syndrome was common but there was no evidence of patterns of co-occurrence of diagnoses being associated with particular syndromes. Receiving a diagnosis was associated with abnormal scores on measures of neuroticism and locus of control, the extent of the abnormality increasing with the number of different diagnoses satisfied. It is argued that the concept of a general neurotic syndrome depends in part on the presence of such predisposing personality factors, and that reduction in this predisposition to neurosis should be the focus of treatment.

The authors examined agreement between parent and child ratings on the Child Behaviour Checklist in a sample of 1299 referred adolescents over a period of three years. Correlations ranged between 0·72 and 0·08 (mean = 0·28), while agreement using kappa was similar but slightly lower (mean = 0·24; range 0·71‐0·07). Agreement on externalizing was higher than on internalizing items, and concordance increased with age for boys, while there were no differences in parent‐child agreement between boys and girls. Agreement was higher for dimensions of behaviour, e.g. depression (r = 0·40).

We asked a sample of 343 adult same-sex twin pairs a number of questions about the similarity of their social environment during childhood and early adolescence. A factor analysis of their responses indicated that their common environment was derived from two sources, one being similar treatment "imposed" upon them by their parents, the other being "elicited" by the twins' similar interests and behavior. Monozygotic (MZ) twins reported experiencing more similar "imposed" and "elicited" environments than dizygotic (DZ) twins. The extent of imposed similar treatment received during childhood and early adolescence was unrelated to either MZ or DZ twins' current behavioral similarity, as indicated by absolute intrapair differences in their Neuroticism, Anxiety, and Depression scores. Similar treatment imposed upon MZ twins on the basis of their zygosity alone is therefore not a threat to the validity of the twin method.

Our results suggest that a substantial proportion of the liability for FBD may be under genetic control. Whether this liability is related to the disorder itself or to other potential predisposing factors requires clarification.

An important contemporary conceptualization of anxiety has suggested that heightened early separation anxiety is specifically associated with the risk of adult panic disorder, with hereditary factors underlying that cluster of anxiety disorders. Yet there is a dearth of studies examining whether early separation anxiety is inherited. The present twin study, based on a retrospective approach, revealed a substantial genetic contribution to separation anxiety in females but not in males, with unique environmental influences being important in both gender groups. Although speculative, an evolutionary explanation is offered to account for the apparent gender difference in the inheritance of early separation anxiety. It is hypothesized that, in some women, phylogenetic vestiges of separation anxiety may conflict with their need to compete in an individualistic manner in the modern workplace. Whether such an attachment-autonomy conflict accounts for the increased rate of panic disorder and agoraphobia in women is worthy of further study.

Our results suggest that a substantial proportion of the liability for FBD may be under genetic control. Whether this liability is related to the disorder itself or to other potential predisposing factors requires clarification.

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