Cannabis: Both Benefits and Risks Explained
What Researchers Found About and Cannabis
The Study at a Glance
Published
Clinical Pharmacology and Therapeutics, 2019
Researchers
Tel Aviv University (Israel)
Study Type
Systematic ReviewKey Finding
Cannabis has both therapeutic potential and documented risks. While cannabinoids show promise for neurological and psychiatric conditions, repeated use is associated with respiratory, cardiovascular, cognitive, and psychiatric adverse effects. The evidence requires careful weighing of benefits against harms.
Key Finding: Cannabis has both therapeutic potential and documented risks. While cannabinoids show promise for neurological and psychiatric conditions, repeated use is associated with respiratory, cardiovascular, cognitive, and psychiatric adverse effects. The evidence requires careful weighing of benefits against harms.
What Researchers Studied About This Condition and Cannabis
Cannabis is the most commonly used illicit drug in the Western world. But what does the science say about both its benefits and its harms?
This comprehensive review from Johns Hopkins University examines the evidence for both the therapeutic potential and the adverse effects of cannabis and cannabinoid-based drugs.
The goal: provide a balanced, evidence-based perspective on a controversial topic.
How This Systematic Review Was Conducted
Researchers conducted a systematic review examining:
• Short-term and long-term side effects of cannabis use • Respiratory and cardiovascular effects • Cognitive and psychiatric effects • Therapeutic potential for medical conditions • Safety considerations for cannabinoid-based drugs
This Condition Treatment Results
The Main Results:
- 1Cannabis associated with respiratory and cardiovascular disorders
- 2Cognitive alterations observed with repeated use
- 3Links to psychosis, schizophrenia, and mood disorders
- 4Therapeutic potential for neurological conditions
- 5Promise for psychiatric disorder treatment
- 6Causal relationships not always established
By the Numbers
| Statistic | What It Means |
|---|---|
| Most popular | illicit drug in Western world |
| Both | benefits AND risks documented |
| Unclear | causation for some adverse effects |
| Growing | use for medical and recreational purposes |
illicit drug in Western world
benefits AND risks documented
causation for some adverse effects
use for medical and recreational purposes
What This Means for This Condition Patients
This balanced review helps you understand both sides of the cannabis debate:
Documented benefits: • Therapeutic potential for neurological disorders • Promise for certain psychiatric conditions • Pain relief and other symptom management
Documented risks: • Respiratory effects (similar to tobacco smoke) • Cardiovascular concerns • Cognitive changes with repeated use • Association with psychosis/schizophrenia • Mood disorder connections
Important nuances: • Many associations don't prove causation • Individual responses vary widely • Risk-benefit balance depends on your situation • Medical use differs from recreational patterns
Bottom line: Cannabis is not simply "good" or "bad." It has real therapeutic potential AND real risks. The right choice depends on weighing benefits against harms for your specific situation, ideally with medical guidance.
Quick Answers: This Condition and Cannabis
Direct answers based on the findings of this study:
Research Summary: Answers are based on published peer-reviewed studies and represent research findings, not medical recommendations. Individual results may vary. Always consult a healthcare provider before making treatment decisions.
Is weed good or bad for you?
It's both—cannabis has real benefits for some conditions (pain, epilepsy) AND real risks (lung/heart effects, cognitive changes, psychosis links). Whether it helps or hurts depends on your situation, how much you use, and your health.
Source: Sholler et al., Clinical Pharmacology and Therapeutics, 2019 (PMID: 30703255)
What are the negative effects of smoking weed?
Documented risks include lung problems, heart effects, memory/thinking changes, and links to psychosis and mood disorders—especially with heavy/repeated use. A Johns Hopkins review found both benefits and harms.
Source: Sholler et al., Clinical Pharmacology and Therapeutics, 2019 (PMID: 30703255)
Does marijuana do more harm or good?
Depends entirely on you and why you're using it. For some conditions (epilepsy, chronic pain) benefits clearly outweigh risks. For recreational heavy use, risks may outweigh benefits. It's not simply "good" or "bad."
Source: Sholler et al., Clinical Pharmacology and Therapeutics, 2019 (PMID: 30703255)
This is educational content, not medical advice
The research summarized here is for informational purposes only. Individual results may vary, and what works in studies may not work the same way for everyone. Always consult with a qualified healthcare provider before making changes to your treatment plan or starting medical cannabis therapy.
Important Limitations
This study has some caveats to keep in mind when interpreting the results:
- Many studies show association, not proven causation
- Difficult to control for other factors in observational studies
- Cannabis products vary in composition
- Long-term medical use less studied than recreational
- Rapidly evolving field requires ongoing updates
The Bottom Line on Cannabis for This Condition
This Johns Hopkins review provides a balanced perspective on cannabis: it has genuine therapeutic potential for neurological and psychiatric conditions, but also documented risks including respiratory, cardiovascular, cognitive, and psychiatric effects. The evidence doesn't support viewing cannabis as either a harmless plant or a dangerous drug—the truth is more nuanced. Patients considering cannabis should weigh the specific benefits against risks for their situation, recognizing that individual responses vary significantly.
Do You Qualify for Medical Marijuana?
If you're living with qualifying condition, you may qualify for a medical marijuana card. Our licensed physicians can evaluate you from home via telehealth.
Related Research & Resources
Related Research
Get Your Card
This condition qualifies for medical marijuana in:
Source
Cohen K, Weizman A, Weinstein A "Positive and Negative Effects of Cannabis and Cannabinoids on Health" Clinical Pharmacology and Therapeutics. 2019. DOI: 10.1002/cpt.1381
Important Information
Study Age: This study was published 7 years ago. Newer research may have updated or refined these findings.
Not Medical Advice: This research summary is for educational purposes only. It should not be used to diagnose, treat, cure, or prevent any disease or medical condition. Always consult a qualified healthcare provider before starting or changing any treatment.
Individual Variation: Research findings represent group averages. Your individual response to cannabis may differ based on genetics, other medications, underlying conditions, and many other factors.
Last reviewed: January 24, 2026
Important Notices
Research Summary Disclaimer
This content represents our interpretation of published scientific research for educational purposes. It should not be used to make treatment decisions without consulting a qualified healthcare provider. Individual results may vary from study findings.
FDA Notice
These statements have not been evaluated by the FDA. Cannabis is not intended to diagnose, treat, cure, or prevent any disease. The FDA has not approved cannabis for any medical condition except specific prescription medications.
Copyright & Fair Use
Research summaries are provided under fair use (17 U.S.C. § 107) for educational purposes. We provide brief summaries with attribution, not full reproductions. All studies remain the intellectual property of their respective authors and publishers.
Data Sources
Study information sourced from PubMed®, U.S. National Library of Medicine. Inclusion does not imply endorsement by NLM, NIH, or the federal government.
For complete information, see our Terms of Use and Research Content Policy.
FAQs: Cannabis for This Condition
Is cannabis good or bad for health?
It's both. Cannabis has documented therapeutic benefits for certain conditions AND documented risks including respiratory, cardiovascular, cognitive, and psychiatric effects. The balance depends on individual circumstances.
What are the long-term effects of cannabis use?
Yes, several risks are documented. Research shows associations with respiratory effects, cognitive changes, and psychiatric conditions (psychosis, mood disorders) with repeated use. Effects vary by individual.
Is medical cannabis safer than recreational use?
Medical cannabis use is typically more controlled (dosing, product quality), but the same drug has similar risks regardless of legal status. Medical supervision may help manage risks better.