Monitored Cannabis Abstinence Was Achievable for Many Schizophrenia Patients

Using contingency management, 42% of cannabis-dependent schizophrenia patients achieved 28 days of verified abstinence, comparable to the 55% rate in non-psychiatric controls.

Rabin, Rachel A et al.·Schizophrenia research·2018·Preliminary EvidenceProspective Cohort
RTHC-01802Prospective CohortPreliminary Evidence2018RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Prospective Cohort
Evidence
Preliminary Evidence
Sample
Not reported

What This Study Found

With contingency management incentives and twice-weekly urine monitoring, cannabis-dependent schizophrenia patients achieved abstinence rates statistically similar to controls (42.1% vs 55%, p=0.53). Both groups showed increased withdrawal symptoms during abstinence, confirming genuine cessation.

Key Numbers

42.1% (8/19) of patients achieved 28-day abstinence vs 55% (11/20) of controls (p=0.53). Quantitative THC-COOH metabolite levels below 20 ng/mL confirmed abstinence.

How They Did This

19 cannabis-dependent schizophrenia patients and 20 non-psychiatric controls underwent 28 days of monitored abstinence with contingency management. Urine was tested twice weekly using qualitative and quantitative methods (GC-MS). Subjective withdrawal assessments were also used.

Why This Research Matters

Cannabis use disorders are about 8 times more common in people with schizophrenia than in the general population. This study shows that structured abstinence programs can work for this population, and at rates not far from the general population.

The Bigger Picture

The high rate of cannabis use disorders in schizophrenia has long concerned clinicians. Demonstrating that structured abstinence is feasible opens doors for studying how stopping cannabis affects psychiatric symptoms and cognitive function in this population.

What This Study Doesn't Tell Us

Small sample size (39 total). Contingency management provides financial incentives that may not reflect real-world motivation. 28 days may not indicate long-term abstinence capacity.

Questions This Raises

  • ?What happens after the incentive structure is removed?
  • ?Does achieving abstinence improve psychiatric symptoms?
  • ?Would longer abstinence periods be achievable with continued support?

Trust & Context

Key Stat:
42% of schizophrenia patients vs 55% of controls achieved 28-day cannabis abstinence (no significant difference).
Evidence Grade:
Preliminary - small pilot study without randomization or control condition for the intervention itself.
Study Age:
Published in 2018.
Original Title:
A method to achieve extended cannabis abstinence in cannabis dependent patients with schizophrenia and non-psychiatric controls.
Published In:
Schizophrenia research, 194, 47-54 (2018)
Database ID:
RTHC-01802

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-ControlFollows or compares groups over time
This study
Cross-Sectional / Observational
Case Report / Animal Study

Enrolls participants and follows them forward in time.

What do these levels mean? →

Frequently Asked Questions

Can people with schizophrenia quit cannabis?

This study found that with structured monitoring and incentives, 42% of cannabis-dependent schizophrenia patients achieved 28 days of verified abstinence - not significantly different from non-psychiatric controls.

What is contingency management for drug use?

Contingency management provides incentives (often financial) for meeting behavioral goals like abstinence, verified through urine testing. This study used it to help cannabis-dependent participants stay abstinent for 28 days.

Read More on RethinkTHC

Cite This Study

RTHC-01802·https://rethinkthc.com/research/RTHC-01802

APA

Rabin, Rachel A; Kozak, Karolina; Zakzanis, Konstantine K; Remington, Gary; Stefan, Cristiana; Budney, Alan J; George, Tony P. (2018). A method to achieve extended cannabis abstinence in cannabis dependent patients with schizophrenia and non-psychiatric controls.. Schizophrenia research, 194, 47-54. https://doi.org/10.1016/j.schres.2017.05.006

MLA

Rabin, Rachel A, et al. "A method to achieve extended cannabis abstinence in cannabis dependent patients with schizophrenia and non-psychiatric controls.." Schizophrenia research, 2018. https://doi.org/10.1016/j.schres.2017.05.006

RethinkTHC

RethinkTHC Research Database. "A method to achieve extended cannabis abstinence in cannabis..." RTHC-01802. Retrieved from https://rethinkthc.com/research/rabin-2018-a-method-to-achieve

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.