Cause of Death in Prison Custody

(Supplementary Tables B1 to B15)

In this section we cover the following topics:

• Summary of Causes of Death in Prison Custody
• Probable Suicide Deaths
• Diseases of the Circulatory System Deaths
• Drug Misuse Deaths and Accidents
• Deaths from Other Causes
• Cancer (malignant neoplasms) Deaths and
• Deaths Involving COVID-19

Summary of Causes of Death in Prison Custody

When a death is registered with National Records of Scotland (NRS), each cause of death listed on the medical certificate cause of death (MCCD) is assigned a code from the International Statistical Classification of Diseases and Related Health Problems (10th Revision) (ICD-10). Following the classification schema, one cause will be defined as the underlying cause of death or the “disease or injury which initiated the chain of morbid events leading directly to death”. NRS statistics are based on the underlying cause of death unless stated otherwise. More information about Death Certificates and Coding the Causes of Death and how NRS attribute cause of death to a case can be found on the NRS website.

Individual cause of death codes can be grouped together to produce analysis of broader causes of death, such diseases of the circulatory system or probable suicide. NRS publish statistics for specific causes of death, on the basis of pre-defined groupings of death codes.

The following table provides a breakdown of deaths in prison custody by cause of death for the period 2012-13 to 2022-23. All causes are based on the underlying cause of death, with the exception of COVID-19, which is based on any mention on the MCCD.

Table 1 shows the total count of each cause of death over the period 2012-13 to 2022-23.

Cause of Death	Number of Cases
Probable Suicide	105
Diseases of the circulatory system	71
Accidents	51
Drug Misuse	50
Other causes	50
Ischaemic (coronary) heart disease	37
Cancer (malignant neoplasms)	36
COVID-19 mentioned	16
Cerebrovascular disease	15
Diseases of the respiratory system	14
Chronic Obstructive Pulmonary Disease	8
Alcohol specific	2
Dementia and Alzheimer’s disease	0

Supplementary table B2 lists the ICD-10 codes that are used to define each cause of death.

Please note that the sum of the deaths by cause is higher than the total number of deaths. This is because some deaths are attributed to more than one cause. As an example, a death that has been classified as Chronic Obstructive Pulmonary Disease (ICD-10 codes J40-44) will also be counted as Diseases of the respiratory system (ICD-10 codes J00-99).

The following table sets out the combinations of overlapping causes of death in prison custody over 2012-13 to 2022-23, and how often each occurs over this reporting period.

Table 2 shows all combinations of multiple causes of death from all deaths in prison custody between 2012-13 and 2022-23.

Cause of Death Combination	Number
Drug misuse and Accidents	47
Diseases of the circulatory system and Ischaemic (coronary) heart disease	37
Diseases of the circulatory system and Cerebrovascular disease	15
Diseases of the respiratory system and Chronic Obstructive Pulmonary Disease (COPD)	8
COVID-19 mentioned and Diseases of the circulatory system	1
Drug misuse and Probable suicide	1
Drug misuse, Probable suicide and COVID-19 mentioned	1

The most frequently occurring causes of deaths in prison custody are examined in further detail in this report.

It is important to note that due to the total number of cases being charted over the 11-year period being relatively small, small volume changes in the number for any year may appear as a substantial change.

Probable Suicide deaths

(Supplementary Tables B4 and B5)

Probable suicide deaths are identified based on the underlying cause of death and additional information. NRS determine whether a death is a probable suicide using the MCCD and information provided by official sources such as the Crown Office and Procurator Fiscal Service. The methodology document that accompanies the NRS publication provides more detail about the specific ICD-10 codes that relate to probable suicide deaths.

This methodology document also sets out that the ICD has separate categories for deaths that can be used depending on the available information. These categories are ‘Intentional Self-Harm”, and “Events of Undetermined Intent”. Events of undetermined inent are “cases where it is not clear whether the death was the result of intentional self-harm, an accident or an assault”(p.3). Because of this, the number of suicides may be over-estimated.  

Between 2012-13 and 2022-23, 105 deaths in prison custody were classified as probable suicide. This is the most common cause of death in prison custody over the reporting period, with probable suicides accounting for around 30% of deaths in prison custody (n=345).

Figure 8 shows the number of probable suicide deaths in prison custody in each year 2012-13 to 2022-23.

The number of probable suicide deaths in each financial year fluctuates across the reporting period. The highest number of probable suicide deaths in prison custody occurred in both 2016-17 and 2021-22, with 15 such deaths recorded in each year. In 2022-23 there were 9 probable suicide deaths, a decrease of 6 from 2021-22. 

Figure 9 shows probable suicides deaths in prison custody plotted alongside all deaths in prison custody, 2012-13 to 2022-23.

While there is a general upward trend in the overall number of deaths in prison custody across the period 2012-13 to 2022-23, the number of probable suicide deaths has not followed the same pattern. However, the number of probable suicide deaths year on year is at a slightly increased level from 2016-17 to 2022-23 when compared against the earlier years in the reporting period.

Method of Suicide

(Supplementary Table B6)

Probable suicide deaths can be classified by method. In their latest probable suicide publication, NRS group probable suicide deaths into three broad categories, showing the change over time. These categories are: ‘Hanging, strangulation, suffocation’, ‘Poison’, and ‘Other’. The table below shows the probable suicide deaths that occurred in prison custody between 2012-13 and 2022-23 categorised by method.

Table 3 shows the method of suicide by NRS category for all probable suicide deaths in prison custody between 2012-13 and 2022-23.

Method of Suicide	Number of Cases	Proportion of Probable Suicide Deaths
Hanging, strangulation, suffocation	96	91.4%
Other	6	5.7%
Poison	3	2.9%

Over 91% of probable suicide deaths occuring in prison custody from 2012-13 to 2022-23 have an underlying cause of ‘X70 Intentional self-harm by hanging, strangulation and suffocation’. This overall trend is consistent with the NRS Probable Suicide report, with hanging, strangulation and suffocation noted as the most common method in probable suicide deaths in the general population over the same time period.

If you are a journalist covering these statistics in the media, please consider following the guidelines issued by Samaritans on the reporting of suicide.

If you are struggling to cope, help is available.

NHS inform has a list of resources available to anyone, with many of these available 24 hours a day.

Samaritans can be called for free on 116 123 (UK and Republic of Ireland) or contacted via email at jo@samaritans.org. Visit the Samaritans website for more information.

Diseases of the Circulatory System deaths

(Supplementary Table B7)

The second most frequent cause of death in prison custody between 2012-13 and 2022-23 was diseases of the circulatory system (ICD-10 codes I00-I99). 71 of the deaths that occurred in prison custody over this period were caused by circulatory system diseases (20.6% overall).

Figure 10 shows the number of deaths in prison custody caused by diseases of the circulatory system in each year 2012-13 to 2022-23.

This chart shows fluctuation in the number of circulatory system deaths in prison custody year on year, with peaks occuring in 2014-15 (11 deaths) and 2022-23 (10 deaths). As such there is no clear overall trend across the time period.

37 deaths caused by diseases of the circulatory system were classified as Ischaemic (coronary) heart disease, while 15 were associated with Cerebrovascular disease. 52 of the 71 (around 73%) diseases of the circulatory system deaths that occurred in prison custody between 2012-13 and 2022-23 fell into either of these subsets.

Drug Misuse deaths

(Supplementary Table B8)

Drug related deaths in Scotland are categorised as drug misuse deaths. As explained in the latest NRS Drug Related Deaths publication, this term has been defined by the Advisory Council on the Misuse of Drugs cross UK working group.

Drug misuse deaths are those with an underlying cause of drug abuse, or where the underlying cause was poisoning and there was a controlled drug present in the body. ‘Controlled drugs’ are those that are listed under the Misuse of Drugs Act (1971). This definition covers both recreational drugs, and some prescribed drugs.

A death is only categorised as a drug misuse death where the drug use has directly caused the death. NRS consult with experts in Public Health Scotland to determine whether individual deaths meet the definition of a drug misuse death. More information about NRS classsification of drugs deaths can be found in their methodology documents. Information about the ICD-10 codes that relate to drug misuse deaths can be found in Annex A of the methodological documents produced by NRS.

Between 2012-13 and 2022-23, there were 50 drug misuse deaths in prison custody. This represents around 14.5% of all deaths in prison custody within this time period.

Figure 11 shows the number of drug misuse deaths in prison custody in each year 2012-13 to 2022-23.

While there are some fluctuations year to year, the number of drug misuse deaths in prison custody has increased over the reporting period. In 2022-23 there were 9 drug misuse deaths in prison custody, a decrease of 3 from the peak of the previous year (12 in 2021-22). While this is a small decrease, the figure for 2022-23 is the second highest point in the time series.

The increase in drug misuse deaths in prison custody is similar to the trend observed in the general population. In their latest Drug-related Deaths publication, NRS reported that “drug misuse deaths in Scotland have generally been increasing over the last two decades.”(p.5), with the highest number of drug misuse deaths in the general population occurring in 2020.

Substances

(Supplementary Tables B9 and B10)

For this report, information on the substances identified in drug misuse deaths in prison custody has been taken from the information on the medical certificate cause of death (MCCD) published by SPS. This information was not published by SPS prior to 2019. Therefore this section only covers the 31 drug misuse deaths in prison custody from 2019 onwards, rather than the 50 drug misuse deaths recorded over the full reporting period (2012-13 to 2022-23).

The information on the MCCD is checked and expanded upon by NRS when drug misuse deaths are coded. NRS receive information from pathologists on the substances involved in drug misuse deaths, which may contain more detail than is available from the MCCD.

For future reporting, the complete information on substances identified in drug misuse deaths will be sought.  

The following table provides a count of the different substances identified on the MCCD in drug misuse deaths in prison custody from 2019 to 2022-23. The number of substances is greater than the number of deaths that have occurred due to multiple substances being identified in some cases. In 28 of the 31 drug misuse deaths occurring, multiple substances were listed on the MCCD or reference was simply made to ‘multi-drug intoxication/ toxicity’.

Table 4 shows the count of each individual substance listed on the MCCD for drug misuse deaths in prison custody from 2019 to end 2022-23.

Substance	Count
Etizolam	14
Buprenorphine	10
Multi-drug Intoxication/ Toxicity	8
Methadone	5
Pregabalin	5
Cocaine	4
Heroin	3
Amitriptyline	3
Tramadol	3
Flubromazepam	2
Flualprazolam	1
Quetiapine	1
Flubromazelam	1
Gabapentin	1
Codeine	1
Diazepam	1
Phenazepam	1
4F-MDMB-BINACA	1
5F-MDMB-PICA	1
Synthetic Cannabinoid Receptor Agonist	1

For summary purposes, substances can be categorised by the family of drugs each belongs to.

Figure 12 shows the prevalence of broad substance types identified on the MCCD in the 31 drug misuse deaths in prison custody between 2019 and 2022-2023.

From the information available, the most common type of substance identified on the MCCD in drug misuse deaths in prison custody from 2019 onwards are ‘Opiates/Opioids’. These are identified in 22 of the 31 drug misuse deaths in prison custody (around 71%).

Twenty of the drug misuse deaths occurring in prison custody from 2019 onwards (around 87%) had a form of Benzodiazepines recorded on the MCCD.

Full information from NRS records on drug misuse deaths occurring in prison custody is needed to explore these patterns further.

Drug Misuse and Accidents 

(Supplementary Table B11)

There is a considerable overlap between deaths in prison custody categorised as drug misuse and those categorised as accidents. Of the 50 drug misuse deaths that occurred in prison custody between 2012-13 and 2022-23, 47 were also categorised as accidents.

The venn diagram below illustrates this overlap.

Figure 13 shows a venn diagram illustrating the overlap between drug misuse and accidental deaths in prison custody, 2012-13 to 2022-23

Looking at the individual ICD-10 codes, this shows that 47 of the drug misuse deaths within the prison population were due to accidental poisonings involving various substances. Of the cases that were not classed as an accidental poisoning, two were recorded as resulting from ‘mental and behavioural disorders’ due to multiple drug use and use of other psychoactive substances and one was a poisoning of undetermined intent. 

The high proportion of drug misuse deaths in prison custody being classified as an accidental poisoning is broadly consistent with the trend found in the general population.

Deaths from other causes

(Supplementary Table B12)

Table 1 of this report shows that 50 deaths in prison custody (around 14.5%) between 2012-13 and 2022-23 were categorised as deaths from ‘other causes’.

These cases are attributed to a range of different chapters within the ICD-10 framework. 

The table below breaks down the deaths from other causes occurring in prison custody 2012-13 to 2022-23 by the ICD-10 chapters attributed to them.

Table 5 contains a breakdown of ICD-10 chapters attributed to ‘other causes’ deaths in prison custody 2012-13 to 2022-23.

ICD Chapter	Number of Deaths
XI - Digestive system diseases (K00-K99)	18
XVIII - Symptoms, signs and abnormal clinical and laboratory findings not elsewhere classified (R00-R99)	7
I - Certain infectious and parasitic diseases (A00-B99)	6
IV - Endrocrine, nutritional and metabolic diseases (E00-E90)	5
VI - Nervous system diseases (G00-G99)	5
XX - External causes of morbidity and mortality (V01-Y98)	3
XII - Diseases of the skin and subcutaneous tissue (L00-L99)	2
XIV - Genitourinary system diseases (N00-N99)	2
II - Neoplasms (C00-D48)	1
V - Mental and behavioural disorders (F00-F99)	1

The most common ICD-10 chapter for deaths in prison custody recorded as occurring from ‘other causes’ is XI - Digestive system diseases (K00-K99), attributed to 18 deaths over the period 2012-13 to 2022-23. These deaths are distributed across a range of different sub-chapters. The largest number of these cases are attributed to K74 – Fibrosis and cirrhosis of the liver (5 deaths).

Cancer (malignant neoplasms) deaths

(Supplementary Tables B13 and B14)

Deaths caused by cancer (malignant neoplasms, listed under ICD-10 codes C00-C97), accounted for 36 (around 10.4%) of all deaths in prison custody between 2012-13 and 2022-23.

Figure 14 shows the number of cancer (malignant neoplasms) deaths in prison custody in each year 2012-13 to 2022-23.

While the number of cancer (malignant neoplasms) deaths in prison custody have fluctuated year on year, the numbers have been at a generally higher level in the second half of the reporting period. Between 2012-13 and 2017-18 there were 15 cancer (malignant neoplasms) deaths in prison custody, compared to 21 between 2018-19 and 2022-23.

Of the cancer (malignant neoplasms) deaths occurring, 14 (38.9%) were recorded as malignant neoplasm of bronchus and lung. This is the most common type of cancer recorded for deaths in prison custody. Ten cancer (malignant neoplasms) deaths in prison custody were categorised as ‘Other’. The category “Other” contains deaths that may fall under sub-categories such as non-Hodgkin’s lymphoma, Leukaemia, and malignant neoplasms of other areas of the body.

Table 6 shows the the most common ICD-10 codes recorded in cancer (malignant neoplasms) deaths in prison custody between 2012-13 and 2022-23.

ICD-10 Code	Number of Deaths
C34 - Malignant neoplasm of bronchus and lung	14
Other	10
C22 - Malignant neoplasm of liver and intrahepatic bile ducts	4
C15 - Malignant neoplasm of oesophagus	3
C18 - Malignant neoplasm of colon	3
C80 - Malignant neoplasm without specification of site	2

COVID-19

(Supplementary Table B15)

In their monthly mortality statistics methodology document, NRS define a death involving COVID-19 as “any death where COVID-19 is mentioned on the death certificate; this can be as the underlying cause of death or as a contributory factor.” 

In total, there were 16 deaths in prison custody that involved COVID-19 (ICD-10 codes U07.1, U07.2, U09.9, U10.9) over the reporting period.

Figure 15 shows the number of deaths in prison custody involving COVID-19 in each year 2020-21 to 2022-23.