Randy Katz

Past and present state examination: the assessment of lifetime ever psychopathology

A Past History Schedule (PHS) for use in conjunction with the Present State Examination (PSE) is described. The PHS/PSE interview enables a rating of lifetime ever psychopathology to be performed. It provides good inter-rater reliability, as well as a satisfactory agreement between retrospective interviews and casenote-based assessment of past psychopathology. The PHS has been devised specifically for use in a family-genetic study of affective illness, but the general approach may be applicable to other categories of psychiatric disorder.

Genetic influences on eating attitudes in a normal female twin population

The Eating Attitudes Test (EAT) and the Eating Disorder Inventory (EDI) were administered to a female volunteer twin population aged 18 to 45 years. Both members of 147 monozygotic (MZ) and 99 dizygotic (DZ) twin pairs completed the questionnaires. Thirty-five subjects scored over the cut-off point of the EAT-26. Interviews of these high-scoring twins and their co-twins identified three subjects with a past history of anorexia nervosa, and three others with a history of a partial syndrome. A heritability value of 41% was obtained for the overall EAT scores, while factor analysis produced a dieting factor with a heritability of 42%. The body dissatisfaction and drive for thinness subscales of the EDI had heritability values of 52 and 44% respectively. The genetic contribution to the variance in body mass index in the twin sample was estimated at 64%. For all the above phenotypes, an environmental model of transmission with heritability constrained to be zero, could be rejected. Conversely, we were unable to reject a purely additive genetic model with shared environmental variance constrained at zero, suggesting that family environment has little or no effect on the transmission of many of these traits.

Nature, nurture and depression: a twin study.

We studied a series of twins systematically ascertained through 214 probands (84 monozygotic, 130 dizygotic) who had had one or more episodes of hospital-treated major depression. A variety of definitions of depression were applied to the co-twins all of which resulted in (a) markedly higher rates of disorder than are found in the general population, (b) significantly higher monozygotic than dizygotic concordance. The results of applying a simple additive model in which depression is considered as a threshold trait suggested that both genetic factors and shared family environment make substantial and significant contributions to the familiality of depression.

Neuroticism in familial depression

This study examined the relationship between personality factors and depression in subjects who may have a familial vulnerability to depression (i.e. first-degree relatives of depressed patients). Four groups comprised our study sample: relatives who had never experienced a psychiatric episode of depression; relatives who had experienced a psychiatric episode of depression but were currently well; relatives who had never experienced a psychiatric episode of depression but were currently depressed; and relatives who had experienced a past history of depression and were currently depressed. Of the four personality characteristics measured (Psychoticism, Extraversion, Neuroticism and Lie), the only significant effects between groups appeared to be attributable to Neuroticism (N). The strongest association was between current illness and N. There was also a tendency for subjects with a past history of depression to have an inflated N score. However, this appeared to be associated with the presence of current depressive symptomatology. Our findings indicate that when current symptomatology is taken into account Neuroticism does not seem to reflect the trait of liability to depression, but is strongly associated with the state of being depressed.

The risk of minor depression before age 65: results from a community survey

Data from a general population survey of psychiatric disorder in Camberwell were used to calculate the risk of a CATEGO-defined depressive episode before the age of 65, using a modification of Strömgrens method. Current depression was defined as cases within the relevant categories of the CATEGO program and at threshold level or above on the Index of Definition (Wing et al. 1978). A past history of depression was elicited using key symptoms such as persistent tearfulness and depressed mood, already enquired after in the course of the PSE, to identify potential episodes, followed by questions to determine accessory symptoms, duration, and degree of social impairment. Clinical judgement was then used to decide whether the disturbance constituted a significant depressive episode. Risk under one set of assumptions was 46% for men and 72% for women. Using another method based on (untenably) conservative assumptions, it became 16% and 30% respectively. The status and implications of these high values are discussed, particularly for genetic studies.

Hazard, heredity and depression. A family study

The relationship between proband characteristics and familial aggregation of depression was assessed in an interview study of 83 families ascertained via probands who had a recent onset of depression. Contrary to expectations and to previous reports in the literature there were no differences between the frequencies of depression in the first degree relatives of probands who had or had not experienced adversity prior to the onset of their illness. Depression was actually slightly more common among the first degree relatives of probands who had experienced a threatening life event compared with the relatives of those who had not. Early onset of depression (before 32 yr) and a neurotic pattern of symptoms in probands were associated with significantly higher rates of current illness in relatives. However, both these differences disappeared when lifetime prevalence or morbid risk to age 65 were considered. Indeed the morbid risk of severe depression in the relatives of endogenously depressed probands was nearly twice that in the relatives of neurotic probands.