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EXECUTIVE SUMMARY

A research team based at the Universities of Edinburgh, Dundee and St Andrews ¹ has been funded by the Scottish Executive's National Programme for Improving Mental Health and Well-being to undertake a detailed epidemiological analysis of suicide ² in Scotland at national and local levels during the period 1989-2004. The study findings are intended to support the implementation of Choose Life, the national strategy and action plan to prevent suicide in Scotland.

Aim, objectives and scope

The broad aim of the project is to support the implementation of Choose Life by providing detailed information on the epidemiology of suicide at national and local levels.

The more specific objectives of the project were defined as:

1. To establish the incidence of suicide in Scotland over the period 1989-2004 ³, including time (temporal) trends ⁴, at national and local levels
2. To describe variation in suicide rates by sex, age and social class ⁵, over the period 1989-2002 ², at national and local levels
3. To examine the relationship between the suicide rate, on the one hand, and the gradient in suicide rates by age and social class ⁵, on the other, over the period 1989-2002 ³, at local level
4. To examine the relationship between the level of socio-economic deprivation ⁵, on the one hand, and the gradient in suicide rates by age and social class ⁵, on the other, over the period 1989-2002 ³, at local level.
5. To compare individual-level estimates of the relationship between suicide and social class ⁵ with area-level estimates of the relationship between suicide and socio-economic deprivation ⁵.

In fact, we were unable to fulfil objectives 3 and 4 because the number of suicide deaths at local level was too small to permit meaningful or interpretable analysis. However, we have considerably extended the study by examining in some detail:

• the allocation of deaths to intentional self harm or undetermined categories, including variation by method and geography ( section 3.1)
• methods of suicide, at national and local levels ( section 3.6)
• suicide rates by area deprivation, at national and local levels, including analyses by gender and age group, and calculation of changes in the social gradient ('suicide gap') ( section 3.9) .

These additional analyses take advantage of a greater range of available data and add value by: highlighting the consequences of adopting a broader definition of suicide; and identifying trends in methods of suicide and the influence of area-level deprivation, thereby contributing to the development of appropriate suicide prevention policy and practice responses.

The main focus of this report is the 14 year period leading up to and including 2002, the year in which Choose Life was launched ⁶. This is consistent with our intention to provide a detailed picture of suicide in Scotland prior to the implementation of the national suicide prevention strategy and action plan. In relation to the examination of suicide trends over time (at both local and national levels) (objective 1) , the analysis is extended to 2004, in order to provide some indication of stability or change in the suicide rate (key outcome measure) during the first two years of Choose Life implementation.

Methods

An anonymised dataset of intentional self harm and undetermined deaths occurring over the period 1989 to 2004 was provided by the General Registrar Office for Scotland ( GROS) . The dataset is confined to deaths among adults aged 15+ years. There were 13185 deaths recorded over the period 1989-2004, of which 74% percent occurred in males (n=9759) and 26% percent in females (n=3426) . The dataset permits description of this sample of deaths by key socio-demographic characteristics. With the exception of 189 deaths which did not have Output Area codes, each death record was assigned by the research team to a 2001 Census Output Area and also to a Consistent Area Through Time ( CATT) . The CATT enables small areas to be reliably compared using data from the 1981, 1991 and/or the 2001 Censuses. On the basis of residential address (postcode sector) , each death was assigned to one of five categories of socio-economic deprivation (Carstairs score) for analysis at the national level and to one of three deprivation categories for analysis at the local level.

Population data were obtained from the mid-year population estimates (from GROS) and from the 1991 and 2001 censuses. Mid-year population estimates provide denominators by sex and age for all suicide rates and standardised mortality ratios ⁷ ( SMRs) , while the census data provide denominators used to calculate suicide rates by social class. Denominators for social class were obtained from census data.

In order to examine local temporal trends in suicide, a three-year moving average of crude suicide death rates was computed separately for males and females in each local area and displayed against the national moving average.

National suicide rates by social class (at death) were computed for males during two time periods (separately) : 1989-1995 (based on 1991 census) and 1996-2002 (based on 2001 census) . The Registrar General's Social Class ( SC) was used as the measure of socio-economic classification. There are five SC categories, with one divided into two subgroups: professional etc (I) , managerial and technical (II) , skilled non-manual (IIIN) , skilled manual (IIIM) , partly-skilled (IV) and unskilled (V) .

The expected numbers of deaths were calculated for each local area using the death rates at the national level. The standardised mortality ratio ( SMR) is thus derived by dividing the observed number of deaths by the expected number of deaths. The age-adjusted ⁸ rate was obtained by multiplying SMR and crude death rate.

Methods of suicide were aggregated into eight categories: hanging, firearms/shooting, jumping, cutting, poisoning/overdose, gassing, drowning, other.

At national level and local levels, suicide death rates by age were calculated. At national level, seven age groups (15-24, 25-34, 35-44, 45-54, 55-64, 65-74, 75 and over) and three age groups (15-44, 45-64, 65+) were used. At local level, because small numbers are involved, only the latter three (broad) age bands were used.

For the area deprivation analysis, age and sex specific deaths from 1996-2002 were used as the numerators while the denominator was obtained from the 2001 Census. This standard population was used for the calculation of suicide SMRs for the 1989-1995 and 1996-2002 periods, to enable comparisons of suicide trends over time.

Main findings

Across the country as a whole male suicide rates increased by 22 percent and female suicide rates by 6 percent over the period.

In about half the local areas suicide incidence over the whole period was not significantly different to national suicide incidence. However, in Glasgow City, the suicide rate was significantly higher than the Scottish average in all years among both men and women. In Glasgow City and a few other local authorities (West Dunbartonshire, Highland, Eilean Siar, Dundee City and Argyll & Bute) all-person standardised suicide mortality ratios ( SMRs) were significantly elevated (compared to Scotland as a whole) . In West Lothian, South Lanarkshire, North Lanarkshire, Fife, Falkirk, East Renfrewshire, East Lothian, East Dunbartonshire, Angus and Aberdeenshire all-person SMRs were significantly lower than the national average.

There was no clear temporal trend in suicide at the local level. Rates tended to fluctuate or exhibit irregular patterns.

Male suicide rates were approximately three times higher than female suicide rates over the period. There was some variation in the male: female suicide ratio between local areas, with a suggestion that male vulnerability to suicide was greater in the more rural and remote areas of the country.

Across Scotland as a whole male suicide rates tended to decline with age, whereas among women there was an inverse U-shaped relationship (lower rates in youngest and oldest age groups) . The highest suicide rate among men (40.8 per 100,000) occurred in 25-34 year age group. High rates were also evident among men aged 35-54 years. Among women, the highest suicide rate (11.6 per 100,000) was found in the 45-54 year age group, with high rates also in the 25-44 year age groups. The excess of suicide deaths among males (approximately fourfold) was particularly marked in the younger age groups (15-34 years) . The age-related pattern found at national level is replicated at local level, although there are some anomalous patterns also ( e.g. highest rate in the oldest age group in a few areas) .

The most common method of suicide among males in Scotland were hanging (7.9 per 100,000) , self-poisoning (6.1) , drowning (3.1) and gassing (3.0) . Among females the most common method of suicide was self-poisoning (4.4 per 100,000) . Hanging suicide rates have significantly increased over time for both men and women, while death rates by gassing (mainly carbon monoxide [car exhaust] poisoning) have significantly decreased. In most local areas the rank ordering of methods and trends over time are similar to what is found at national level. The main difference is the greater popularity of drowning as a method of suicide in Highland and the islands.

At the national level there was a marked variation in male suicide rates by social class. Differences between rates in the non-manual groups were not statistically significant. However, there were significant differences between rates in the non-manual groups and social class IIIM, between IIIM and IV, and between IV and V. The slope of the social class gradient was more pronounced in 1996-2002 than in 1989-1995. Similar patterns and trends were found in local areas.

Across Scotland there was a strong relationship between suicide and socio-economic deprivation: the higher the level of deprivation, the higher the standardised suicide mortality ratio. The 'relative gap' between SMRs, calculated by dividing the SMR for the most deprived quintile by the SMR for the least deprived quintile, was larger ('widening gap') in 1996-2002 compared to 1989-1995. The magnitude of the widening gap was similar for men and women. Although the relative gap was higher among people aged 15-44 years than among people aged 45+ years, the widening gap was more pronounced in the older age group than in the younger age group. An analysis of suicide and socio-economic deprivation within local areas reveals evidence of a relative suicide gap in all but a few local authorities and health boards. A widening suicide gap over time was found in 24 (out of 32) local authorities and 12 (out of 15) health boards.

The suicide rate was found to be significantly higher in class V than in other social classes in all local areas, irrespective of the degree of socio-economic deprivation. In 1989-1995 the patterning of social class differences does not differ markedly between categories of socioeconomic deprivation. This that the main influence on suicide rates is at the individual, rather than area, level. In 1996-2002, however, there is evidence of a trend towards an increase in the social class gradient as the level of socioeconomic deprivation worsens: that is to say, the gap between suicide rates in the highest and lowest social classes increases as the level of socio-economic deprivation worsens. However, the compositional effect (the influence of individual social class) is undoubtedly far stronger than the area effect (the influence of the level of socio-economic deprivation in the locality) .

Implications

Social class and socio-economic deprivation

• The study findings suggest the need to give greater priority to the effects of social class (at individual level) and socio-economic deprivation (at area level) in local and national suicide prevention strategy and action plans.
• Targeted action is warranted in areas with high suicide rates where there is evidence of impact of socio-economic deprivation (eg Glasgow) .
• However, according to the analyses reported here, it is not enough to target suicide prevention activities exclusively on areas of social disadvantage, because this will not meet the needs of people who are in the lowest social classes but who live outside areas of economic deprivation. The analyses indicate that the influence of individual social class is far stronger than the influence of the level of socio-economic deprivation in the area.
• Addressing higher suicide risk in lower socio-economic groups would be consistent with Scottish Executive's wider strategies on promoting social justice and social inclusion, reducing social inequality and tackling health inequalities
• In addition to considerations of social class and socio-economic deprivation, the ratio of male to female age-adjusted suicide rates indicates a higher level of vulnerability to suicide among men in the more rural and remote areas in the country.

Supporting the national suicide reduction target

• If the recent reduction in suicide incidence is to be sustained in years to come, the public, government, policy makers, agencies, planners, academics, mass media and practitioners need to understand the role that suicide prevention activity in general, and Choose Life in particular, is playing and has played. In this context, it is important to note that in Scotland Choose Life sits in the broader context of health improvement, public health work and wider work on social justice (as part of the Executive's National Programme for Improving Mental Health and Well-being) . Initiatives such as 'Scottish Mental Health First Aid,' the 'Breathing Space' telephone line, the 'see me' anti-stigma campaign, work on recovery and social inclusion are all likely to be contributing to the recent reduction in the suicide rate in Scotland. Work on improving health and social care services, such as the recent emphasis on addressing depression and improving the delivery of mental health services (Delivering for Mental Health) may also be impacting on the suicide rate, as well as wider social, economic and public policy factors.
• To support the implementation of Choose Life, more detailed and up to date information about the epidemiology of suicide is needed, both nationally and locally. GROS has collected and collated a considerable amount of information on each suicide (or possible suicide) death in Scotland, but relatively little has been published to date. An in-depth exploration of these data would help to inform planners and practitioners about the suicide situation in Scotland.

Links with the evaluation of the first phase of Choose Life

This study was commissioned as part of a wide programme of research and evaluation to support the implementation of Choose Life. The evaluation of the first phase of Choose Life was published in September 2006 and members of the evaluation team also worked on this project. Findings from this study reinforce several of the recommendations made by the evaluation team. In particular:

• Enhanced focus on inequalities. The evaluation highlighted the omission of socio-economic deprivation and low socio-economic status from priority groups in the Choose Life strategy.
• Targets at local levels. Because the number of suicides and undetermined deaths fluctuates annually, it is not easy to translate a 10 year national target into meaningful local area targets, particularly in areas where the number of suicide deaths per annum is small. To maximise the engagement and continuing contribution of local areas towards the national 10 year target, it may be worthwhile considering the introduction of local targets.
• Possible 'proxy' target. One possible candidate would be non-fatal self harm incidence, operationally defined as admissions to hospital following self-poisoning and/or self-injury, although admissions to hospital and medical or psychosocial 'seriousness' are not perfectly correlated. Many (perhaps even the majority) of those treated in hospital will not represent a high suicide risk, and a small but significant minority of those who do not attend hospital (not referred or refusing to attend) will be high risk and will go on to die by suicide.

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