Psychiatric disorders are more severe among suicide victims of higher occupational level

EDITOR—Agerbo et al reported that people with a history of mental illness and a high income are at greater risk of committing suicide than their counterparts with a lower income.1 The authors, and Gunnell in a commentary on their paper, suggested that possible explanatory factors for this finding were the presence of a more severe mental illness or the stigmatising effects of psychiatric admission; they called for further studies measuring the severity of the psychiatric illness.

Because Finland has one of the world's highest death rates from suicide2 and most of the population is treated in public hospitals (regardless of socioeconomic status) we examined this issue. We explored whether suicide victims with senior occupations or higher socioeconomic status, or both, more commonly had mental disorders or psychoses or misused alcohol or drugs than did other people. We also investigated whether the method of suicide was somehow related to the occupation.

We used a large, prospectively collected, 13 year database of all suicides (1296 males, 289 females) during 1988-2000 in northern Finland (the province of Oulu). Details of the database and study protocols have been reported.3 The lifetime diagnoses of the suicide victims, based on psychiatric admissions and relevant codes from the international classification of diseases, were extracted from the Finnish hospital discharge register until the end of 1999. Our definitions for psychotic disorders were identical with those of Agerbo et al.

The proportion of admissions due to psychoses was higher in people in senior positions or with a high level of education than in other employed people (table). Thus Agerbo et al's findings were supported. In addition, these patients had more days of hospital treatment; this perhaps indicated more severe manifestations of psychoses, as suggested by Gunnell.1 The proportion of admissions with any psychiatric disorder was highest among retired people; that in the people with the most senior jobs, however, did not differ from that in the other occupational groups. The admissions due to alcohol or drug misuse did not differ between occupational groups.

Violent methods of suicide are associated with low impulse control.4 In our study the method of suicide was less commonly violent in the highest occupational group. This might reflect non-impulsiveness in these suicides. It seems possible therefore that people in high income groups are more determined and that, because of the stigmatising effect, their suicides are better planned than those of people from lower income groups.

Direct association between social status and risk of suicide was not found in Germany

EDITOR—Agerbo et al report that in Denmark people with a history of mental illness and a high income are at greater risk of suicide than lower income groups.1 In his accompanying commentary Gunnell says that relative poverty is typically associated with an increased risk of suicide; hence residual confounding may underlie the findings. We do not agree that there is a general inverse association between socioeconomic status and mortality from suicide; cultural factors and their influence on risk of suicide must be considered.

We used cases of suicide reported on death certificates in Germany in 1998 to estimate the risk of suicide for two population subgroups: the 7.4 million residents of non-German nationality and the 12.7 million residents of the former East Germany. The residents of non-German nationality, many of whom are from Turkey, make up 9% of the total population of Germany; as a group they have lower socioeconomic status, rising unemployment, reduced access to health care, and problems of cultural adaptation. The residents of the former East Germany constitute 18% of the total German population; their access to clinical care does not differ substantially from that of people in the former West Germany.

The table shows the relative risk of suicide for non-German nationals (424 cases) versus Germans (11 214 cases) and former East Germans (2363 cases) versus former West Germans (8851 cases). Non-German nationals are at a lower risk of suicide relative to Germans at all ages, despite their lower socioeconomic status. Germans in the former East Germany have a higher relative risk. This cannot be a consequence of the economic decline in the former East Germany after reunification in 1990 since the relative risk was highest in those aged over 84 (1.79 (95% confidence interval 1.42 to 2.24) in men; 1.93 (1.44 to 2.56) in women). Moreover, suicide rates have been higher in the former East Germany for at least 50 years yet have declined since the mid-1980s.2

The association between socioeconomic status and nationality and place of residence in our dataset is merely ecological. Nevertheless, our findings indicate that there must be factors modifying the association between socioeconomic status and risk of suicide. Nationality might imply a different cultural or religious acceptability of suicide (for example, in Turkish Muslims). Likewise, suicide may have been culturally more acceptable in the former East Germany.

Our findings show that the association between socioeconomic status and mortality from suicide is not always inverse and is far from straightforward.

Neomycin should not be used to treat hepatic encephalopathy

EDITOR—In their clinical review on portal hypertension Krige and Beckingham mention neomycin as treatment for hepatic encephalopathy.1 Although neomycin has been used as a standard treatment of hepatic encephalopathy for almost 40 years, there is no evidence that the drug is effective. The only randomised, placebo controlled study found no benefit of neomycin compared with standard treatment alone.2 Also, the combination of neomycin with lactulose was not superior to placebo.3 On the basis of these negative studies and the potential for serious adverse effects of this drug, neomycin should not be prescribed for hepatic encephalopathy. Other antibiotics, including paromomycin, metronidazole, vancomycin, and rifaximin, are better tolerated, and several randomised controlled trials support their efficacy. 4 5