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Drug use and prisons
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Dame Carol Black's Review of Drugs provides a detailed overview of drug use and prisons.

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Drug use and prisons

This is the ninth in a series of posts based on perhaps the most important drug-related report of the current century, Dame Carol Black’s Review of Drugs. Today’s post looks at the section from that report dedicated to drug use and prisons.

Dame Carol identifies three overlapping cohorts of drug users and drug-related offenders currently in the prison treatment system:

Carol Black drugs in prison groups

She goes on to profile prisoners in drug treatment:

  • Nearly 3/4 of adults received drug treatment in prison for less than six months.
  • This reflects their short sentences, particularly for opiate users.
  • Less than 5% received treatment for two years or more.


The report goes on to estimate the total prevalence of people in custody on a given day due to their drug use or for drug specific offences, based on three key assumptions:

  1. Those with drug offence sentences greater than two years will be in prison for trafficking and will be separate from the treatment cohort; 
  2. All those sentenced for possession will be in the treatment cohort; 
  3. All those on remand will also be in the treatment cohort.

As you can see from the table below, it is estimated that over 1/3 of people in prison are there for drug specific offences or offending related to their drug use.

Prison drug treatment

The report presents a detailed profile of adults in prison drug treatment:

  • There were nearly 50,000 people in contact with prison based drug treatment in 2017 18.
  • A fall of about 9% over the last three years.
  • Just under 60% were receiving treatment for opiates, which is a lower proportion than community treatment (73%).
  • Proportionally there are far less women in prison treatment than in the community with 1 in 10 overall and 1 in 20 for non opiates.
  • This will in part reflect that only 5% of the total prison population are female.
  • The ethnic breakdown for opiate users in treatment is very similar in prison as it is in the community.
  • However there is more difference in users of other substances with 84% White in the community compared to 75% in prison.
  • The largest differences are seen in Caribbean, Other Black and African ethnic groups. Again this will in part reflect the make up of the general prison population.
  • More opiate users presenting to prison treatment are also using crack cocaine, possibly reflecting the higher harms related to this polydrug use.
  • There is also a slightly higher % of people presenting with crack use (not with opiates) in prison.
  • People receiving treatment in prison tend to be younger than those treated in the community.
  • With the non opiate prison population being similar in age distribution as the general prison population.
  • And the opiate prison population being significantly older.

Importantly, the report flags up just how vital prison drug treatment is with many individuals not engaged with community drug services:

  • Over 60% of opiate users in prison treatment in 2017/18 were not in contact with community treatment.
  • Less than 1 in 10 users of other drugs were also in contact with community treatment in the year.
  • Just over 10% of opiate users had never been in contact with community treatment.
  • This compares to nearly half of non opiate users who have never had community treatment.
  • Overall almost nine out of ten people receiving treatment for non opiates had either not been treated in the community in the last 12 months or had never been treated.


Dame Carol points out that short prison sentences mean that prison drug treatment is rarely long enough to be effective and that community sentences would be more appropriate. Her key findings include:

  • Short sentences mean that prison treatment is not long enough to be effective and patterns of drug use and offending are likely to continue post release with poor continuity of care into community treatment for those that need it.
  • Positive drug test rates fell between 1999 and 2015 but have increased since then for traditional drugs and also because of t he introduction of tests for psychoactive substances.
  • The number of illicit drug finds has increased substantially over the last three years, but the increases have been in line with the overall rise in illicit seizures from prisoners. Therefore it is difficult to tell whether the increase is due to increased drug use or better  detection equipment and processes.
  • Rates of drug finds per person by prison function are relatively similar, though rates of positive tests vary substantially.
  • By prison, both rates of drug finds and positive drug tests show significant variation. Those prisons with the highest rates of drug use have the worst ‘purposeful activity’ HMP Inspectorate scores.
  • Psychoactive substance use has increased over the last few years, mainly driven by the use of ‘spice’. While this increase is causing substantial problems for users and staff, there is no evidence so far that this type of drug use continues on release.

Thanks to Andy Aitchison for kind permission to use the header image in this post. You can see Andy’s work here.

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