# Cannabis Science Full Report: What a Five-Year Low Back Pain Cannabis Cohort Can and Cannot Tell Us > **Author:** Benjamin Caplan, MD (ABFM Board Certified, MA Lic. #240562, NPI: 1962722637) > **Publisher:** CED Clinic (https://cedclinic.com) > **Canonical URL:** https://cedclinic.com/medical-cannabis-chronic-low-back-pain-five-year-study/ > **Published:** 2026-06-26T13:12:07-04:00 | **Last Modified / Clinically Audited:** 2026-09-28T10:50:27-04:00 > **Clinical Summary:** A five-year medical-cannabis cohort study in chronic low back pain reported large improvements, but its uncontrolled design requires careful interpretation. --- CED Clinical Relevance #79 Strong Clinical Relevance This is a fresh human chronic-pain paper with unusually long follow-up and direct counseling relevance, but its uncontrolled single-center design sharply limits causal conclusions. Clinical Insight | CED Clinic A new five-year study of inhaled [medical cannabis](https://cedclinic.com/therapeutic-benefits-of-thc/) in treatment-refractory chronic low back pain is clinically interesting because it reports very large improvements in pain, disability, and medication use over time. It is clinically risky if read too casually. The study is a retrospective analysis of prospectively collected outcomes from one Israeli center, with no concurrent control group and each patient compared against their own pre-cannabis baseline. That means the paper is useful for hypothesis generation and expectation-setting, but it does not prove that cannabis itself caused the magnitude of benefit reported. Chronic Low Back Pain[Medical Cannabis](https://cedclinic.com/therapeutic-benefits-of-thc/)Long-Term Follow-UpObservational StudyCaution Audience Pain clinicians, primary-care clinicians, patients with chronic low back pain, caregivers, and cannabis-medicine clinicians Primary Topic How to interpret a five-year inhaled medical-cannabis cohort study in treatment-refractory chronic low back pain Source [Read the full study](https://pubmed.ncbi.nlm.nih.gov/42351683/) A five-year retrospective analysis of 241 treatment-refractory chronic low back pain patients reported large improvements during inhaled medical-cannabis therapy, alongside major reductions in concomitant pain-medication use. The paper is worth reading because long-term data are rare. It is worth reading skeptically because the design cannot safely establish causality. What This Study Teaches Us This paper teaches that long-term real-world cannabis cohorts can look much more positive than short randomized trials. That does not automatically make the result wrong. It does mean readers have to work harder on bias, comparator choice, retention effects, and the difference between reported improvement and proven treatment effect. Why This Matters Chronic low back pain is common, disabling, and often treated with imperfect options. Patients regularly ask whether [medical cannabis](https://cedclinic.com/therapeutic-benefits-of-thc/) can help pain, sleep, function, and reliance on other medications over the long term. This study matters because it speaks directly to those questions with unusually long follow-up. It also matters because the effect sizes are so large that the paper can easily be overread if the design limitations are pushed to the margins. Study Snapshot Study Type Retrospective analysis of prospectively collected single-center outcomes Population Adults with treatment-refractory chronic low back pain in a tertiary orthopedic clinic Participants 241 consecutive patients Exposure Inhaled medical cannabis, predominantly smoked, with THC 4-22% and CBD 2-22% Comparator Each patient’s documented pre-cannabis baseline during conventional therapy Follow-Up Five years Pain Signal Mean NRS change at Year 5 was -5.36 points Function Signal ODI improved by -17.68 points and BPI interference by -3.41 points Medication Signal Reported opioid use fell from 100% at baseline to 4.6% at Year 5 Safety Pattern Recorded adverse events were mostly mild, but follow-up occurred inside a treatment program rather than a randomized safety framework Important Limitation No concurrent control group, major risk of selection, survivorship, expectancy, and regression-to-the-mean bias Journal Biomedicines Published May 30, 2026 PMID 42351683 DOI 10.3390/biomedicines14061255 Clinical Bottom Line The study is clinically relevant because it describes what happened in a long-running medical-cannabis cohort with severe chronic low back pain. It is not proof that inhaled cannabis reliably causes the reported five-year gains, and it should not be translated into simple product recommendations or opioid-sparing promises. What the Cohort Reported The investigators analyzed 241 adults with treatment-refractory chronic low back pain who entered a tertiary orthopedic medical-cannabis program between 2020 and 2025. Outcomes included pain intensity, disability, and pain interference, with follow-up reported out to five years. By Year 5, the paper reported large average improvements on the Numeric Rating Scale, Oswestry Disability Index, and Brief Pain Inventory, along with marked reductions in concomitant opioid, NSAID, antidepressant, and gabapentinoid use. Why the Result Looks So Striking Long-term cannabis papers rarely report this much follow-up, and the effect sizes here are much larger than what most short randomized pain trials usually show. That alone makes the paper important to examine carefully. The authors also describe very high retention and a predominantly mild adverse-event profile. If those patterns reflected a true treatment effect with limited bias, they would represent an unusually strong chronic-pain signal. Why Causal Claims Stay Unsafe This was not a randomized trial, and it did not include a concurrent control group receiving usual care, another analgesic strategy, or placebo. Each patient was effectively compared with their own pre-cannabis history, which leaves major room for regression to the mean, expectation effects, selection into treatment, and survivorship in the program. The study population came from one center, product exposure was heterogeneous, and the highest-risk claims concern exactly the outcomes that are most vulnerable to bias in open clinical cohorts: pain, disability, and medication behavior over time. How to Translate This Safely The responsible translation is not that cannabis has now been proven to transform chronic low back pain for most patients. The responsible translation is that some patients in a closely followed real-world program reported substantial long-term improvement while using inhaled cannabis, and that signal deserves comparison against stronger trial designs. For patients and clinicians, this means the paper can support a careful conversation about goals, monitoring, function, side effects, and alternative explanations. It cannot justify self-directed inhaled-cannabis escalation or broad opioid-replacement claims. How Strong Is This Evidence? The paper is stronger than anecdote because it includes a defined cohort, prospectively collected outcomes, long follow-up, and clinically meaningful endpoints in a high-need pain population. Its evidence ceiling remains limited because there was no randomized assignment, no concurrent comparator, no stable product definition, and no clean way to isolate cannabis from time, expectation, co-treatment, and retention effects. Where This Paper Deserves Skepticism The skepticism here should be unusually active, not performative. When an uncontrolled cohort reports effect sizes this large with 92.9% still on treatment at Year 5, the first job is not to dismiss the study but to ask what design features could inflate apparent benefit. The biggest concerns are selection into treatment, who stayed versus who left, within-patient historical comparison, product heterogeneity, and the temptation to treat medication reduction as proof that cannabis caused the improvement. What This Paper Does Not Show This study does not show that inhaled cannabis cures chronic low back pain, that similar results should be expected in other populations or settings, that smoking cannabis is the best route, that one THC:CBD ratio is optimal, or that cannabis should replace established pain care. It also does not prove a causal opioid-sparing effect. How This Fits With the Broader Clinical Conversation Chronic low back pain is exactly the kind of condition where patients care about long-term function, daily activity, and medication burden, not just short-term pain scores. That makes this paper clinically attractive. It is also exactly the kind of condition where uncontrolled treatment cohorts can look better than randomized trials because symptom severity, treatment-seeking behavior, and life circumstances fluctuate over time. The most useful reading keeps both truths in view: long-term observational data matter, and they still require stronger trials before they become clinical proof. Dr. Caplan’s Take *I understand why this paper will get attention. Five-year follow-up in a difficult chronic-pain population is not trivial, and clinicians do need more long-term data than the field usually provides.* *What keeps this useful instead of misleading is restraint. I would discuss it as a strong observational signal that raises serious questions worth testing better, not as a settled answer about inhaled cannabis for chronic low back pain.* What a Careful Reader Should Take Away A careful reader should come away with a balanced conclusion: the study reports meaningful long-term improvement in a real-world chronic low back pain cohort, but its design leaves too much uncertainty to convert that signal into proof or routine recommendation. Evidence Interpretation Guide Table of Contents - [How to Read a Five-Year Cannabis Low Back Pain Study Without Mistaking It for Proof](#How_to_Read_a_Five-Year_Cannabis_Low_Back_Pain_Study_Without_Mistaking_It_for_Proof)[A Better Reading Order for This Cohort Study](#A_Better_Reading_Order_for_This_Cohort_Study) - [The Same Study Can Mean Different Things Depending on the Question Being Asked](#The_Same_Study_Can_Mean_Different_Things_Depending_on_the_Question_Being_Asked)[Long-Term Relief Is the Hope, Not the Promise](#Long-Term_Relief_Is_the_Hope_Not_the_Promise) - [Useful Counseling Data With a High Bias Burden](#Useful_Counseling_Data_With_a_High_Bias_Burden) - [The Design Can Magnify Benefit](#The_Design_Can_Magnify_Benefit) - [Function and Medication Burden Matter](#Function_and_Medication_Burden_Matter) - [Mild Adverse Events Do Not End the Safety Conversation](#Mild_Adverse_Events_Do_Not_End_the_Safety_Conversation) - [Observational and Randomized Evidence Answer Different Questions](#Observational_and_Randomized_Evidence_Answer_Different_Questions) - [Monitor Goals, Function, and Impairment Together](#Monitor_Goals_Function_and_Impairment_Together) - [The Next Step Is Better Comparative Pain Trials](#The_Next_Step_Is_Better_Comparative_Pain_Trials) - [Frequently Asked Questions](#Frequently_Asked_Questions)[Related](#Related) ## How to Read a Five-Year Cannabis Low Back Pain Study Without Mistaking It for Proof Long follow-up can make a paper feel automatically stronger. Sometimes it is. Sometimes it mainly makes the results feel more persuasive than the design can support. The safest reading starts with admiration for the duration of follow-up and ends with discipline about what an uncontrolled cohort can actually establish. ### A Better Reading Order for This Cohort Study **Start with the comparator**Ask what the study compared cannabis against. Here, the comparator was each patient’s earlier conventional-therapy state, not a concurrent randomized control group. **Check retention before celebrating**High retention can be clinically interesting, but it can also reflect who stayed in a treatment program long enough to keep reporting outcomes. **Separate symptom change from causation**Large reductions in pain and disability matter, but in an uncontrolled cohort they do not tell you how much of the change was caused by cannabis itself. **Keep product and route specificity visible**This study involved inhaled medical-cannabis products in one regulatory and clinical setting. It does not validate every dispensary product or every route of administration. The Main Research Question What happened over five years in a treatment-refractory chronic low back pain cohort treated with inhaled medical cannabis in a real clinical program? The Practical Patient Question If I am considering medical cannabis for chronic low back pain, should this paper change my expectations about long-term pain, function, medication use, and side effects? The Bottom Line This paper can sharpen a clinical conversation, but it cannot replace individualized care or better-controlled evidence. CED Perspective Lens ## The Same Study Can Mean Different Things Depending on the Question Being Asked Scientific papers rarely answer a single question. Patients, clinicians, researchers, and critics can read the same data differently. These evidence-based lenses show where this trial is useful, where it remains uncertain, and how easily it can be overstated. Overview The same chronic-pain cohort can look encouraging, overhyped, practical, or incomplete depending on which question the reader asks first. These eight lenses help keep the signal and the uncertainty together. #### Long-Term Relief Is the Hope, Not the Promise If you live with chronic low back pain, it makes sense to notice that this cohort reported improvement in pain, disability, and medication use over several years. It also matters that this was not a randomized proof study. The paper supports a conversation about possibilities and tradeoffs, not a guarantee that inhaled cannabis will help you the same way. Lens takeaway Use the study to ask better questions, not to assume you will match the cohort. #### Useful Counseling Data With a High Bias Burden Clinicians can use this paper to discuss what some patients report over long follow-up in a regulated cannabis program, especially around function and medication trajectories. But the counseling value depends on naming the biases clearly. Without that, the paper can be mistaken for proof of efficacy and proof of opioid sparing. Lens takeaway Discuss the cohort as signal-rich but causally weak. #### The Design Can Magnify Benefit A skeptical read should focus first on the lack of concurrent control, the within-patient historical comparison, and the unusually favorable long-term retention profile. Those features do not erase the reported improvements, but they do make it impossible to assign the observed gains confidently to cannabis alone. Lens takeaway Strong results in a weak design are a reason to inspect harder, not to celebrate faster. #### Function and Medication Burden Matter Pain care is not only about a numeric pain score. Disability, activity interference, and the broader treatment burden are also meaningful outcomes for patients with long-standing low back pain. This paper is valuable partly because it keeps those outcomes visible. It is incomplete because it cannot show whether a different pain strategy might have produced similar changes. Lens takeaway The outcomes matter; the comparator is the weak point. #### Mild Adverse Events Do Not End the Safety Conversation The paper describes mostly mild adverse events, which is reassuring at first glance. But safety in an open treatment program is not the same thing as safety adjudication in a blinded controlled trial. Sedation, impairment, falls risk, cognitive effects, and inhalation-related concerns still need patient-specific review, especially over long-term use. Lens takeaway A favorable cohort safety profile should inform caution, not replace it. #### Observational and Randomized Evidence Answer Different Questions This cohort tells us what a long-running clinical program observed. Randomized pain trials tell us more about average causal effects under controlled conditions. When the cohort looks much stronger than the trial literature, the right move is synthesis and skepticism, not choosing whichever evidence layer feels more hopeful. Lens takeaway Use the cohort for context and trials for calibration. #### Monitor Goals, Function, and Impairment Together If medical cannabis is considered, follow-up should track pain, mobility, work tolerance, sleep, medication changes, impairment, and adverse effects in a structured way. That practical monitoring frame is more defensible than assuming long-term benefit because one observational paper reported dramatic averages. Lens takeaway Concrete monitoring matters more than optimistic interpretation. #### The Next Step Is Better Comparative Pain Trials What this study most clearly earns is a better-designed next study: clearer product definitions, concurrent controls, stronger safety capture, and longer comparative follow-up. The field does not need more generic cannabis-pain rhetoric. It needs low back pain trials that can separate durable benefit from durable bias. Lens takeaway The paper should accelerate better trials, not end the debate. Join the Conversation Have a question about how this applies to your situation? [Ask Dr. Caplan](https://benjamincaplan.com/ask-dr-caplan) Want to discuss this topic with other patients and caregivers? [Join the forum discussion](https://cedclinic.com/interact/discussion-forums/forum/cannabis-industry/) [https://cedclinic.com/contact/](https://cedclinic.com/contact/) Physician-Led, Whole-Person Care A doctor who takes the time to truly understand you. Personal care that starts with listening and is guided by experience and ingenuity. Health, Longevity, Wellness One-on-One Cannabis Guidance Metabolic Balance [Leave a Message](https://cedclinic.com/contact/) [Metabolic Care](https://cedclinic.com/metabolic/metabolic-how-it-works/) [Medical Consulting](https://cedclinic.com/book/) [Cannabis Care](https://cedclinic.com/book/) [https://cedclinic.com/contact/](https://cedclinic.com/contact/) Share this Evidence Watch [X](https://twitter.com/intent/tweet?text=Cannabis+Science+Full+Report%3A+What+a+Five-Year+Low+Back+Pain+Cannabis+Cohort+Can+and+Cannot+Tell+Us&url=https%3A%2F%2Fcedclinic.com%2Fmedical-cannabis-chronic-low-back-pain-five-year-study%2F) [LinkedIn](https://www.linkedin.com/sharing/share-offsite/?url=https%3A%2F%2Fcedclinic.com%2Fmedical-cannabis-chronic-low-back-pain-five-year-study%2F) [BlueSky](https://bsky.app/intent/compose?text=Cannabis+Science+Full+Report%3A+What+a+Five-Year+Low+Back+Pain+Cannabis+Cohort+Can+and+Cannot+Tell+Us%20https%3A%2F%2Fcedclinic.com%2Fmedical-cannabis-chronic-low-back-pain-five-year-study%2F) [Instagram](https://www.instagram.com/drcaplan/) [Substack](https://doctorapprovedcannabis.substack.com/) [RSS](https://cedclinic.com/feed/) Source: [Long-Term Inhaled Cannabis Therapy for Chronic Low Back Pain: A Five-Year Retrospective Analysis of Prospectively Collected Patient-Reported Outcomes in 241 Treatment-Refractory Patients.](https://pubmed.ncbi.nlm.nih.gov/42351683/) Related Reading at CED Clinic Continue exploring the evidence [High-Dose CBD Significantly Reduced Neuropathic Pain in Spinal Cord Injury: What a New RCT Reveals](https://cedclinic.com/high-dose-cbd-neuropathic-pain-spinal-cord-injury/) A more controlled pain-study design that helps calibrate how observational cannabis pain signals can differ from randomized evidence. [Read the RCT](https://cedclinic.com/high-dose-cbd-neuropathic-pain-spinal-cord-injury/) [Endocannabinoid System and Opioids: What a New Review Says About Pain and OUD](https://cedclinic.com/endocannabinoid-system-opioid-use-disorder-review/) Broader CED context on how cannabinoid-pathway pain discussions intersect with opioid-related clinical questions without collapsing one into the other. [Review the context](https://cedclinic.com/endocannabinoid-system-opioid-use-disorder-review/) [Cannabinoids for Cancer Pain: New Review Questions the Opioid-Sparing Claim](https://cedclinic.com/opioid-sparing-cancer-pain-cannabinoids-meta-analysis/) Useful counterweight because it shows how opioid-sparing cannabis claims can weaken under more controlled evidence review. [Compare the caution](https://cedclinic.com/opioid-sparing-cancer-pain-cannabinoids-meta-analysis/) Similar Studies on CEDClinic.com Earlier coverage on closely related evidence When a new paper overlaps with earlier CED Clinic coverage, we preserve the chain instead of hiding the overlap. These links point to older related posts so readers can compare what is new, what is repeated, and how the evidence has moved. Earlier CED coverage on low-back-pain [cannabis research](https://cedclinic.com/pediatric-cannabis-certification-care-children/) [Dronabinol for Chronic Low Back Pain: What the Veterans Trial Will Actually Test](https://cedclinic.com/dronabinol-chronic-low-back-pain/) CED coverage of a randomized Veterans trial protocol for oral dronabinol in chronic low back pain. Similar because both pieces focus on chronic low back pain and cannabinoid-based interventions. Different because the dronabinol paper was a protocol, while the current paper reports long-term observational outcomes from inhaled medical cannabis. [Compare the trial design](https://cedclinic.com/dronabinol-chronic-low-back-pain/) Earlier CED coverage on low-back-pain [cannabis therapeutics](https://cedclinic.com/firearms-regulatory-guidance-cannabis/) [FDA Grants Cannabis Extract VER-01 Breakthrough Therapy Status for Pain](https://cedclinic.com/fda-breakthrough-therapy-cannabis-ver-01-chronic-pain-treatment/) CED coverage of a regulated full-spectrum extract positioned around phase 3 low-back-pain evidence and FDA breakthrough status. Similar because both posts speak to chronic low back pain and cannabinoid-based treatment signals. Different because VER-01 coverage centered a regulated product with controlled-trial framing, while the current study is a single-center long-term cohort. [Compare the product context](https://cedclinic.com/fda-breakthrough-therapy-cannabis-ver-01-chronic-pain-treatment/) Earlier CED coverage on chronic-pain program outcomes [Medical Cannabis Linked to Meaningful Pain-Related Improvements in Large Minnesota Study](https://cedclinic.com/medical-cannabis-linked-to-meaningful-pain-related-improvements-in-large-minnesota-study/) CED coverage of observational state-program data linking medical cannabis with pain-related functional improvement. Similar because both pieces report observational chronic-pain outcomes in medical-cannabis settings. Different because the Minnesota post emphasized short-term function signals, while the current paper emphasizes five-year low-back-pain follow-up and medication trajectories. [Compare the real-world evidence](https://cedclinic.com/medical-cannabis-linked-to-meaningful-pain-related-improvements-in-large-minnesota-study/) ## Frequently Asked Questions What type of study was this? It was a retrospective analysis of prospectively collected outcomes from a single-center medical-cannabis cohort, not a randomized controlled trial. Who was studied? The paper analyzed 241 adults with treatment-refractory chronic low back pain treated in a tertiary orthopedic clinic. What kind of [cannabis therapy](https://cedclinic.com/cannabis-based-therapies-smoking-cessation/) did patients receive? Patients used inhaled medical-cannabis products, predominantly smoked, with THC concentrations ranging from 4% to 22% and CBD concentrations ranging from 2% to 22%. What outcomes improved in the paper? The paper reported large average improvements in pain intensity, disability, pain interference, and reductions in use of several concomitant pain-related medications by Year 5. Does this prove cannabis caused those improvements? No. Without a concurrent control group, the study cannot confidently separate a cannabis effect from selection bias, expectancy, regression to the mean, retention effects, or other treatment changes over time. Why is the lack of a control group such a big issue? Because [chronic pain](https://cedclinic.com/cannabinoids-pain-management-opioid-alternative/) symptoms and treatment behavior can change for many reasons over time. A concurrent control helps show whether similar patients improved without the same cannabis exposure. Does this prove an opioid-sparing effect? No. The reported reduction in opioid use is clinically interesting, but in an uncontrolled cohort it cannot be treated as proof that cannabis itself caused the change. How should clinicians use this paper? Clinicians can use it to inform careful counseling about long-term observational signals, while making the design limits explicit and keeping monitoring goals concrete. Should patients take this as a reason to start smoking cannabis for back pain? No. The paper does not validate self-directed smoking, specific retail products, or unsupervised long-term use for chronic low back pain. What is the safest bottom-line interpretation? The study reports a meaningful long-term chronic-pain signal in a real-world medical-cannabis cohort, but the evidence remains observational and cannot justify broad causal or prescribing claims on its own. ### Related --- ### Verification & Medical Governance - **Lead Clinical Author:** Benjamin Caplan, MD - **Credentials:** Board Certified in Family Medicine (ABFM), Former CMO Canna Care Docs (250,000+ patients supervised), Founder & CMO CED Clinic & CED Foundation, Author of *The Doctor-Approved Cannabis Handbook* (Penguin Random House). - **Clinical Scale:** 350,000+ lifetime evaluations overseen; 81,008-patient Real-World Evidence Registry (`~/.ced_rwe_vault.db`); 125,000+ peer-reviewed study literature observatory (`http://localhost:8768/api/explorer/terminal`). - **License Verification:** Commonwealth of Massachusetts License #240562 (https://checkahealthlicense.mass.gov/). - **NPI Registry:** 1962722637 (https://npiregistry.cms.hhs.gov/provider-view/1962722637). - **Ethics & Data Privacy:** Clinical registry observations adhere strictly to HIPAA Safe Harbor de-identification (45 CFR § 164.514(b)) and criteria for secondary research exemption under 45 CFR § 46.104(d)(4).