Research into neurodegenerative diseases has found a promising ally in the endogenous cannabinoid system. This article explores the use of cannabinoids to alleviate spasticity and pain in multiple sclerosis, analyzing the available data.
In brief
- The endogenous cannabinoid system offers new pathways for symptomatic management in neurodegenerative diseases, especially in multiple sclerosis (MS).
- Sativex (nabiximols) is approved by the AEMPS as a second-line treatment for moderate to severe spasticity refractory to other medications.
- Observational studies confirm its long-term efficacy and safety, although they do not demonstrate a modification of the disease’s immunological course.
- The route of administration (spray vs. vaporized) can influence individual response, suggesting a need for personalized treatment.
- It is crucial to distinguish between symptomatic relief and a cure, while always maintaining a harm reduction approach and clinical prudence.
A new therapeutic horizon for neurodegenerative diseases
Diseases affecting the central nervous system represent one of the most complex challenges for modern medicine. As life expectancy increases in our countries, the impact of conditions like multiple sclerosis (MS) becomes increasingly visible and relevant. These conditions not only progressively deteriorate a patient’s physical and cognitive abilities but also generate a significant emotional and economic burden for their families and the healthcare system.
Traditionally, advances in neuroscience have been slow in this specific area. Available treatments are often limited to slightly delaying progression or alleviating specific symptoms, with high costs and side effects that frequently complicate the patient’s life. However, the discovery of the endogenous cannabinoid system has opened an interesting door: our own body possesses receptors (primarily CB1) in a large number of central nervous system structures. This suggests that pharmacological manipulation of this system could offer useful tools to modulate difficult symptoms.
Multiple sclerosis: A complex landscape
After epilepsy, MS is the most frequent neurological disease in young adults. It affects approximately one in every thousand people, is more common in women than in men, and constitutes a leading cause of paralysis in the West.
Under normal conditions, the central nervous system is protected by the blood-brain barrier. In MS patients, this barrier is compromised, allowing immune system cells to cross into the interior and attack myelin. This substance acts as an electrical insulator around neurons; its destruction (demyelination) prevents the correct transmission of nerve impulses, causing a wide range of motor, sensory, and cognitive symptoms.
Sativex: The approved drug and its therapeutic position
Since 2010, a medication known as Sativex (nabiximols) has been marketed in Europe. It is an oromucosal spray containing a fixed ratio of cannabinoids adapted from cloned plants: 27 mg/ml of THC and 25 mg/ml of CBD, along with small amounts of other active compounds.
The official indication is clear: it is prescribed as an add-on treatment to improve symptoms in patients with moderate to severe spasticity due to MS who have not responded adequately to other antispastic medications. Therefore, it is considered a second-line drug.
Initial clinical trials showed that between 40% and 50% of patients discontinued treatment due to a lack of efficacy or significant adverse effects within the first few weeks. However, those who tolerated it well experienced a notable improvement in muscle stiffness, pain, and urinary symptoms.
Long-term evidence: Safety and effectiveness
Initial approval was based on short-term studies. Subsequently, crucial research evaluating the long-term use of the drug was published. An observational study conducted between 2010 and 2016 analyzed data from more than 940 patients with extensive follow-up.
The results were encouraging: 83% of cases showed improvement due to the treatment, with 60% of participants maintaining long-term therapy. No signs of abuse or dependence were detected, nor were there serious long-term side effects that had not been previously known. It is also interesting to note the individual variations in skills such as driving: while some patients reported worsening, others noted improvements, which underscores the need for individualized supervision.
Alternative routes and treatment personalization
Research has not stopped at the oromucosal spray. Recent studies have explored the use of medicinal cannabis via vaporization (for example, with varieties such as Bedrocan) in patients who did not respond to the authorized spray. In a series of controlled cases, those who tried the oral or inhaled route obtained therapeutic effects superior to those of the spray in a significant number of patients.
This suggests that the response may depend heavily on the route of administration and the patient’s individual characteristics. Furthermore, research on real-world quality of life has confirmed palpable improvements in balance, walking ability, and muscle flexibility, beyond what is simply indicated by numerical scales.
Harm reduction and critical reading
It is essential to approach this topic with prudence. Although cannabinoids have demonstrated symptomatic efficacy, there is no robust scientific evidence that they slow the progression of the disease or modify its immunological course in the long term.
Furthermore, access to these treatments remains unequal in Spain, depending on the hospital and the treating neurologist. It is important to distinguish between what is a first-line drug (such as baclofen, gabapentin, or tizanidine) and a second-line one. Often, conventional treatments have limitations in efficacy or significant side effects, which has led some experts to reconsider the current therapeutic hierarchy.
Prudence is key: one should not promise miraculous cures or underestimate potential risks. Pharmaceutical marketing often presents new drugs with excessive enthusiasm, but in the case of neurodegenerative diseases, the evidence must be rigorous and balanced.
Toward more conscious medicine
Twelve years after the start of the first significant clinical trials, we have a much broader body of evidence on the therapeutic use of cannabis to alleviate symptoms in MS. However, its role in other neurodegenerative pathologies such as Parkinson’s, Alzheimer’s, or amyotrophic lateral sclerosis (ALS) remains to be investigated.
At Psiconáutica.org, we understand that the use of psychoactive substances must always be accompanied by a critical reading and an approach focused on holistic health. Science advances step by step, and each new piece of data brings us closer to more effective and safer treatments for those who need them.
This article is part of our series on therapeutic cannabis, where we explore with scientific rigor and human sensitivity how these tools can improve quality of life without falling into unfounded expectations. The next installment will address other neurological diseases, continuing this necessary dialogue between medicine, science, and society.
Article written by Fernando Caudevilla (DoctorX) for Psiconáutica.org
