86% of Kenyan Methadone Patients Tested Positive for Cannabis at Baseline | Research

The takeaway

Among 874 methadone patients in Nairobi, cannabis use was extremely common at 85.8% at baseline and remained high at 62.7% during follow-up, alongside widespread polysubstance use.

Addiction medicine specialists; public health professionals working in sub-Saharan Africa; researchers studying polysubstance use in opioid treatment.

85.8% cannabis prevalence at methadone enrollment

What the researchers found

Cannabis prevalence was 85.8% at baseline and 62.7% during follow-up among methadone patients. Opioids, cannabis, and benzodiazepines were the most commonly co-used substances. University education was associated with lower cannabis use (OR 0.1).

Why it matters

Methadone programs in sub-Saharan Africa are relatively new, and understanding co-occurring substance use patterns is critical for designing effective treatment. The extremely high cannabis prevalence suggests it should be addressed as part of opioid treatment.

The numbers in context

Baseline cannabis prevalence: 85.8% (95% CI 83.3-88.0). Follow-up prevalence: 62.7% (95% CI 59.5-65.8). Mean age: 35.3 years. 76% unemployed. 51.4% had primary-level education. 48.5% divorced or separated. University education OR for cannabis use: 0.1 (95% CI 0.02-0.8).

How the study worked

Retrospective study of 874 patients enrolled in a methadone maintenance program in Nairobi, Kenya, from December 2014 to November 2018. Cannabis use was determined by urine drug screens. Demographic data was collected from patient files.

What this study cannot tell us

This is a single-site study in one Kenyan city. Urine drug screens detect recent use but do not measure frequency or quantity. The retrospective design limits the ability to determine whether cannabis use affected methadone treatment outcomes.

How to read the evidence

Moderate: large sample from a real-world clinical setting, though limited to a single site and retrospective design.

When this study was published

Published in 2022, covering data from 2014-2018.

The bigger picture

Most research on cannabis use in opioid treatment comes from North America and Europe. This study highlights that polysubstance use patterns in East Africa may require different treatment approaches, particularly given the much higher cannabis co-use rates than typically reported in Western settings.

Questions still open

Does cannabis use during methadone treatment affect retention or opioid relapse rates in this population? Would integrated cannabis interventions improve methadone treatment outcomes? How do these patterns compare to other East African methadone programs?

Common questions

Did cannabis use decrease during methadone treatment?

Cannabis prevalence dropped from 85.8% at baseline to 62.7% during follow-up, suggesting some reduction, but rates remained high. The study could not determine whether methadone treatment caused the decline.

Why was cannabis use so high in this group?

The study did not investigate reasons, but the high rates likely reflect both the general pattern of polysubstance use among people with opioid dependence and the specific drug use context in Kenya.

Read the original research

The prevalence and pattern of cannabis use among patients attending a methadone treatment clinic in Nairobi, Kenya.

Substance abuse treatment, prevention, and policy, 17(1), 12

View on PubMed ↗Publisher’s paper ↗

Citation

Ngarachu, Elizabeth Wambui; Kiburi, Sarah Kanana; Owiti, Frederick R; Kangethe, Rachel. (2022). The prevalence and pattern of cannabis use among patients attending a methadone treatment clinic in Nairobi, Kenya.. Substance abuse treatment, prevention, and policy, 17(1), 12. https://doi.org/10.1186/s13011-022-00437-7