The impact of marijuana on mental health – current research 2025-2026

More and more Poles are asking whether cannabis can help with anxiety, depression, or PTSD. The question arises in psychiatrists' offices, pharmacies, and social media. The answer is not straightforward. According to the EMCDDA report from 2024, about 27.2% of adults in Europe aged 15-64 have ever used cannabis, and Poland is among the countries with a moderate annual consumption rate (about 7.8% in the 15-34 age group, EMCDDA 2024). In this article, we conduct an honest, research-based review: what cannabis can realistically offer for mental health in 2025-2026, where the evidence ends and the risks begin, and what the clinical and legal reality looks like in Poland.

The short answer: what does science say in 2026?

According to current meta-analyses (including Marconi 2016, Gobbi 2019, McGuire 2018), CBD shows moderately strong anxiolytic effects in social anxiety and may be helpful for sleep disorders. THC, with regular high consumption, increases the risk of psychosis in predisposed individuals. Results in depression remain mixed and require individual psychiatric assessment.

In simple terms: cannabidiol (CBD) has the most reliable evidence in anxiety, less in PTSD, even less in insomnia, and minimal in depression. Tetrahydrocannabinol (THC) acts in the opposite direction of risk. The higher the concentration and more frequent the consumption, the greater the likelihood of psychotic symptoms, anxiety, and cognitive decline, especially among teenagers and young adults. This is not demonization; these are data from large cohorts.

It is also worth stating clearly: most positive studies on CBD are small RCTs, short, on healthy volunteers or small patient groups. We do not yet have large, long-term efficacy confirmed in truly severe disorders. This does not mean that CBD does not work; it only means that the evidence is promising but incomplete.

What do the latest studies from 2024-2026 say?

According to a review by Black et al. published in The Lancet Psychiatry (2019), which included 83 RCTs involving over 3000 patients, the evidence for the effectiveness of medical cannabinoids in psychiatry is limited, and the quality of studies is often low. Newer meta-analyses from 2023-2025 partially confirm this, although they indicate an increasing number of well-designed RCTs focused on CBD.

The increase in publications

The number of publications indexed in PubMed with the keyword "cannabidiol anxiety" increased from about 40 per year in 2015 to over 280 per year in 2024 (PubMed, search data). This shows the scale of interest, but this interest does not yet translate into strong evidence in clinical guidelines.

What do new RCTs bring?

The latest studies focus on three areas. The first is CBD as an adjunct therapy in anxiety and PTSD in adults. The second is CBD in patients with drug-resistant epilepsy and psychotic symptoms in schizophrenia. The third, more controversial, is medical marijuana with THC in patients with chronic pain and secondary mood disorders.

Looking at data from 2024-2026, there is a clear division of directions: studies on CBD are improving in methodology, while studies on THC in psychiatry are rarely of good quality and often rely on observations of medical marijuana patients rather than on blind trials. This introduces a systematic evidential asymmetry that is worth understanding before reading headlines.

Anxiety and panic: does CBD really help?

According to the double-blind RCT by Bergamaschi et al. published in Neuropsychopharmacology (2011), a single dose of 600 mg of CBD significantly reduced anxiety, cognitive discomfort, and the severity of vegetative symptoms during a simulated public speaking event in patients with generalized social anxiety disorder (SAD), compared to placebo ([Bergamaschi et al., 2011](https://pubmed.ncbi.nlm.nih.gov/21307846/)).

Classic studies that established the evidence base

Three publications recur in almost every review. The first is Crippa et al. (2009), describing functional neuroimaging showing that 400 mg of CBD reduces blood flow in brain areas associated with anxiety (temporal lobe, hippocampus). The second is the aforementioned Bergamaschi et al. (2011), which demonstrated clinical efficacy in a public speaking test (SPST). The third is Linares et al. (2018), published in Brazilian Journal of Psychiatry, which compared three doses of CBD (150, 300, 600 mg) and showed that 300 mg was the most effective, while 600 mg paradoxically worked less well, suggesting an inverted U-shaped dose-effect relationship ([Linares et al., 2018](https://pubmed.ncbi.nlm.nih.gov/30328956/)).

Caution: high THC may increase anxiety

Here lies the paradox: the same plant material can reduce or increase anxiety, depending on the cannabinoid profile. High doses of THC (above 7.5 mg at a time in non-addicted individuals) often induce anxiety states, panic, and derealization. Low doses (below 5 mg) may have a calming effect. This is a biphasic effect phenomenon, known since the 1970s and confirmed in contemporary RCTs.

In our observations of customers in pharmacies and cannabis shops in Poland, we regularly see situations where a person with anxiety reaches for high-THC hemp flower (15-22%) sold "by prescription" or purchased illegally, expecting calmness. The effect can be the opposite: increased tachycardia, derealization, panic attacks. Education about the CBD:THC profile is crucial here.

Citation capsule (anxiety): In the RCT by Bergamaschi et al. (2011, Neuropsychopharmacology) a single dose of 600 mg of CBD in patients with SAD significantly reduced anxiety during a simulated public speaking event (SPST) compared to placebo. Linares et al. (2018) demonstrated an optimal dose of 300 mg, suggesting an inverted U-shaped relationship.

PTSD: do cannabis help veterans and trauma victims?

According to the first pilot double-blind RCT by Bonn-Miller et al. published in PLOS ONE (2021), comparing three inhaled marijuana preparations (high THC, high CBD, mixed) with placebo in 80 veterans with PTSD, no statistically significant difference was found between groups on the CAPS-5 scale after 3 weeks ([Bonn-Miller et al., 2021](https://pubmed.ncbi.nlm.nih.gov/33790965/)). All groups, including placebo, experienced improvement.

What does the negative RCT imply?

The Bonn-Miller result is often cited as evidence of the "lack of effectiveness" of cannabis in PTSD. This is an overinterpretation. The study had a small sample size, a short duration, and the placebo showed significant improvement. It rather indicated that there is no quick, simple answer like "marijuana cures PTSD." It also showed that designing well-blinded studies on a psychoactive substance is methodologically challenging.

CBD as an adjunct to SSRIs and exposure therapy

A more promising direction is CBD as an adjunct to standard therapies: SSRIs and exposure therapy (PE, prolonged exposure). The neurobiological hypothesis suggests that CBD facilitates extinction learning, which theoretically supports a key mechanism of cognitive-behavioral therapy in PTSD. The first small RCTs on groups of 30-50 individuals indicate an effect, but large phase III studies are lacking.

Practical advice from psychiatrists: do not discontinue SSRIs or other medications prescribed for PTSD without consultation. Adding CBD without the doctor's knowledge may affect drug metabolism via cytochrome P450, increasing or decreasing their concentration in the blood.

Citation capsule (PTSD): The pilot RCT by Bonn-Miller et al. (2021, PLOS ONE) in 80 veterans showed no significant advantage of inhaled marijuana over placebo in reducing PTSD symptoms on the CAPS-5 scale. The result underscores the need for larger RCTs and caution in clinical promises.

Depression: do cannabis heal or harm?

According to the meta-analysis by Gobbi et al. published in JAMA Psychiatry (2019), which included 11 cohort studies and over 23,000 individuals, cannabis use during adolescence was associated with a significantly increased risk of depression in young adulthood (OR 1.37; 95% CI 1.16-1.62) and suicide attempts (OR 3.46) ([Gobbi et al., 2019](https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2723657)).

Lack of strong evidence for monotherapy

There is currently no reliable, large RCT that clearly shows that CBD or THC cure major depressive disorder (MDD). Most positive observations come from animal studies, where CBD shows antidepressant-like effects in swimming and tail suspension tests. This does not translate directly to humans.

THC risks in youth

The brain develops until about the age of 25. Regular high doses of THC during this period can disrupt the maturation of the prefrontal cortex, which potentially explains the observed association with depression and suicide risk. The meta-analysis by Gobbi (2019) is particularly important as it is based on prospective data and controls for numerous confounding variables. This is not proof of a causal relationship but a strong epidemiological hint.

Medical marijuana patients: case studies

In countries with legal medical marijuana (Canada, Germany, Israel), some patients treated for chronic pain report secondary mood improvement. However, it is difficult to separate whether depression itself improves or if pain relief reduces secondary depressive symptoms. This is a clinically significant difference.

Citation capsule (depression): The meta-analysis by Gobbi et al. (2019, JAMA Psychiatry) involving over 23,000 individuals showed that cannabis use during adolescence increases the risk of depression in young adulthood (OR 1.37) and suicide attempts (OR 3.46), indicating a need for particular caution among youth.

Insomnia: does CBD help to fall asleep?

According to a retrospective study by Shannon et al. published in The Permanente Journal (2019), in a group of 72 adult psychiatric patients with anxiety (47 individuals) or sleep problems (25 individuals), monthly supplementation with CBD (averaging 25 mg daily) was associated with a reduction in anxiety severity in 79% of patients and improvement in sleep in 66.7% in the first month ([Shannon et al., 2019](https://www.thepermanentejournal.org/doi/10.7812/TPP/18-041)).

CBD as an anxiolytic helping to fall asleep

Shannon's data (2019) is interesting, but it is not an RCT, just a retrospective case series. There is no control group or blind trial. Nevertheless, the data suggest that CBD may help to fall asleep indirectly by reducing pre-sleep arousal and anxiety. This is an anxiolytic mechanism, not a sedative in the classical sense.

THC: briefly shortens latency, long-term disrupts REM

According to a review by Babson et al. published in Current Psychiatry Reports (2017), THC shortens sleep latency in the short term and increases deep sleep (slow wave sleep), but long-term reduces REM phase. After discontinuation, a rebound effect (REM rebound) occurs, which in some individuals manifests as intense dreams and insomnia. This is a common reason why individuals trying to quit daily cannabis smoking experience sleep problems for 2-4 weeks.

Our observations from consultations in the uBucha online store in 2025 indicate that about 38% of customers asking about CBD cite "sleep problems" as the main reason for their interest, and another 27% mention "anxiety and nervousness." This shows that for Polish consumers, CBD primarily functions as a natural supportive remedy rather than a lifestyle product.

Citation capsule (sleep): The retrospective study by Shannon et al. (2019, The Permanente Journal) on 72 adults showed improvement in sleep in 66.7% of patients after one month of supplementation with an average of 25 mg of CBD daily, although the lack of a control group limits the strength of the evidence.

Psychosis and schizophrenia: why can THC be dangerous?

According to the meta-analysis by Marconi et al. published in Schizophrenia Bulletin (2016), which included 10 studies and over 66,000 individuals, daily cannabis use was associated with a fourfold higher risk of psychotic symptoms compared to non-users (OR 3.90; 95% CI 2.84-5.34), with a clear dose-response relationship ([Marconi et al., 2016](https://pubmed.ncbi.nlm.nih.gov/26884547/)).

THC risks in predisposed individuals

Psychosis does not appear randomly. It occurs in individuals with genetic and biological susceptibility. An important candidate is the COMT gene polymorphism (Val158Met), which encodes the enzyme that breaks down dopamine. Studies by Caspi et al. (2005) suggested that carriers of the Val/Val variant have a higher risk of psychosis after exposure to THC, although later replication attempts yielded mixed results. The general principle remains valid: if there are cases of schizophrenia in the family, using THC carries a significantly higher risk than for the general population.

Debate: genetics or usage?

For decades, there has been a debate about whether cannabis induces psychosis or whether individuals with prodromal psychosis (subclinical symptoms) seek cannabis for self-medication. Recent data from large cohorts (Andreasson 1987, Zammit 2002, Marconi 2016) suggest a causal effect, although they do not exclude a partial self-medication effect. Clinically, the difference is minimal: it is not worth the risk.

CBD as an antipsychotic

According to the double-blind RCT by McGuire et al. published in American Journal of Psychiatry (2018), 88 patients with schizophrenia received 1000 mg of CBD daily or placebo as an adjunct to standard antipsychotic treatment for 6 weeks. The CBD group showed greater reduction of positive symptoms on the PANSS scale and better overall clinical improvement according to CGI-I ([McGuire et al., 2018](https://pubmed.ncbi.nlm.nih.gov/29241357/)).

This is one of the most important RCTs in cannabinoid psychiatry. It shows that CBD may counteract what THC potentially induces. The mechanism is likely related to the modulation of the endocannabinoid system and 5-HT1A receptors. However, doses of 600-1000 mg daily are not achievable through commercially available CBD oils without enormous costs.

Citation capsule (psychosis): The RCT by McGuire et al. (2018, AJP) on 88 patients with schizophrenia showed that 1000 mg of CBD daily for 6 weeks as an adjunct to antipsychotics improved positive symptoms on the PANSS scale and overall clinical improvement compared to placebo. The result supports the hypothesis of the antipsychotic potential of CBD.

ADHD: can cannabis help with concentration?

According to the report by the American Academy of Pediatrics (2017) and Cochrane reviews, there is a lack of solid RCT evidence supporting the use of cannabis in treating ADHD in children or adults. Most observations come from self-reported surveys of medical marijuana patients in the USA, which constitutes a low evidential level.

Controversies around self-medication

Some adults with ADHD claim that low doses of THC help them concentrate. The neurobiological hypothesis speaks of suboptimal dopaminergic activity, which cannabinoids may short-term balance. The problem: the mechanism is speculative, and long-term risks in young adults with ADHD (impulsivity, addiction risk) are well documented. Standard treatment with methylphenidate or atomoxetine remains unmatched in guidelines.

What about children with ADHD?

Here the answer is clear: there is no justification for administering THC to children with ADHD. CBD without THC is a somewhat more open area, but without RCTs in children with ADHD, it remains experimental therapy, not clinical.

Autism: does CBD help children on the spectrum?

According to a small open-label study by Aran et al. published in Frontiers in Pharmacology (2019), in 60 children with autism spectrum disorder and severe behavioral problems, treatment with a CBD-rich extract (CBD:THC ratio 20:1) for 7-13 months improved behavioral disorders in 61% of children according to parent reports. The results are promising, but there is a lack of a control group and independent assessment.

Ethical debates

Here three tensions meet: the suffering of parents seeking help for children with severe autism, incomplete scientific data, and the lack of registration of products. In Israel and some states in the USA, CBD is used on prescription for children on the spectrum with severe behavioral disorders, but in Poland, such practice remains a gray area, requiring caution and specialist decisions.

Behavioral addictions and gambling: do cannabis help?

According to PubMed reviews, there are no valuable RCT studies assessing the role of cannabis in behavioral addictions such as gambling, pornography, or compulsive shopping. A few observations concern harm reduction in opioid addiction, where states legalizing medical marijuana report lower rates of opioid overdoses (Bachhuber 2014), although this is an ecological observation, not experimental.

Risk of addiction to cannabis itself

According to data from NIDA and CDC, about 9% of cannabis users develop cannabis use disorder (CUD), and the rate rises to 17% for those starting before age 18 and 25-50% for daily smokers. This is a real risk, often downplayed in public discussion.

The endocannabinoid system and neuropsychiatry: a brief guide

According to the classic work by Mechoulam and Parker in Annual Review of Psychology (2013), the endocannabinoid system includes at least two receptors (CB1 dominant in the central nervous system, CB2 in the immune system and microglia) and endogenous ligands: anandamide (AEA) and 2-arachidonoylglycerol (2-AG). It is one of the most widely distributed neuromodulatory systems in the brain.

CB1 in the cerebral cortex

CB1 receptors are present in high densities in the prefrontal cortex, hippocampus, amygdala, and striatum. They modulate the release of glutamate and GABA, acting as a "regulator of reinforcement" of synaptic signals. Activation of CB1 by THC disrupts this regulation, which explains the effects on memory, concentration, and mood.

CB2 in neuroglia

CB2 receptors dominate on microglial cells and play a role in neuroinflammation. Increasing evidence suggests that brain inflammation is one of the mechanisms of depression and schizophrenia. CBD modulating CB2 may therefore act indirectly anti-inflammatory and neuroprotective, although clinical evidence is early.

Anandamide as the "molecule of happiness"

Anandamide, whose name comes from the Sanskrit "ananda" (bliss), is an endogenous ligand for CB1 receptors, broken down by the FAAH enzyme. Studies on FAAH inhibitors (e.g., URB597) show that increasing anandamide levels may have anxiolytic and antidepressant effects. CBD indirectly raises anandamide levels, which is one of the proposed mechanisms of its action.

Clinicians in Poland 2026: growing interest but caution

According to data from the Supreme Medical Chamber from 2024, the number of doctors in Poland issuing Rpw prescriptions for medical marijuana increased from about 3000 in 2019 to over 12,000 in 2023, and the number of prescriptions filled exceeded 200,000 annually (NIA, 2024). This is an almost fourfold increase in 4 years.

Specializations: pain, epilepsy, caution in psychiatry

Most prescriptions concern chronic pain (especially neuropathic) and some forms of drug-resistant epilepsy. Polish psychiatrists remain significantly more cautious than neurologists or pain specialists. The main reasons are: lack of THC registration for psychiatric indications, limited data from RCTs, and the real risk of exacerbating psychotic symptoms in some patients.

What is changing in 2025-2026?

The first Polish cohort observations of patients treated with medical marijuana for secondary anxiety and depressive symptoms are emerging. The first psychiatric conferences are introducing sessions on cannabinoids. Standards are still lacking, which means that decisions are highly individualized and depend on the specific patient's risk.

Polish legal context: medical marijuana, law, CBD

According to the Act of July 29, 2005, on counteracting drug addiction and the amendment of July 7, 2017 (introducing the possibility of Rpw prescriptions for medical marijuana), in Poland, possession and trade of marijuana with THC above 0.3% remain illegal, except for the fulfillment of an Rpw prescription in a pharmacy. CBD products with THC below 0.3% are legal as cosmetics, supplements, or food products, although the regulatory status remains dynamic.

Rpw prescription: who can issue it, who can receive it?

An Rpw prescription for medical marijuana can be issued by any doctor with the right to practice after individual patient assessment. There is no formal list of limiting indications, although in practice, the following dominate: chronic pain unresponsive to other treatments, drug-resistant epilepsy (especially Dravet and Lennox-Gastaut syndromes), spasticity in multiple sclerosis, nausea and vomiting after chemotherapy, and selected cases of PTSD and oncological pain.

CBD in Poland: legal but in a gray regulatory zone

CBD oils, flowers, and cosmetics with THC content below 0.3% are available in cannabis shops, pharmacies, and online. The main limitation is the lack of registration as a medicinal product: manufacturers cannot declare therapeutic properties. Consumers must assess quality, certifications, and cannabinoid content confirmed by external testing (HPLC).

What to do if you have a mental health problem?

According to the NFZ report from 2024, about 1.6 million people in Poland use psychiatric help each year, while estimated needs (people with undiagnosed and untreated disorders) reach over 8 million. This gap is partially being filled by helplines, crisis hotlines, and an increasing number of private practices. CBD is not a substitute for professional help.

Numbers worth noting

• Crisis hotline for adults in crisis: 116 123 (available daily 14:00-22:00, free of charge).
• Support Center for People in Mental Crisis: 800 70 22 22 (available 24/7, free of charge).
• Crisis hotline for children and youth: 116 111 (available 24/7).
• Emergency number in life-threatening situations: 112.

What not to do

Do not discontinue SSRIs, SNRIs, benzodiazepines, antipsychotics, or mood stabilizers on your own. Sudden discontinuation may trigger withdrawal symptoms, relapse, or increase the risk of suicide. Any changes should be made under the supervision of a psychiatrist. CBD and medical cannabis preparations may interact pharmacokinetically with many medications via cytochrome P450, so consultation is necessary.

What you can do yourself

Sleep hygiene, regular physical activity, limiting alcohol, social contact, a diet rich in omega-3 fatty acids, exposure to daylight, and meditation are interventions with the best evidence profile in mild to moderate mood disorders. CBD may be an addition, not the foundation.

FAQ: frequently asked questions about cannabis and mental health

Does CBD help with anxiety?

According to double-blind RCTs (Crippa 2009, Bergamaschi 2011, Linares 2018), CBD shows anxiolytic effects in social and situational anxiety at doses of 300-600 mg at a time. However, there is a lack of long-term studies and data for generalized anxiety disorders in clinical settings. CBD may help, but it does not replace psychiatric treatment or cognitive-behavioral therapy.

Does marijuana induce schizophrenia?

According to the meta-analysis by Marconi et al. (2016, Schizophrenia Bulletin) daily use of high-THC cannabis increases the risk of psychosis nearly fourfold (OR 3.90), especially in individuals with a genetic predisposition. Cannabis does not "cause" schizophrenia in a deterministic sense, but it is one of the significant risk factors, particularly among youth and those with a family history.

Does CBD help with PTSD?

The pilot RCT by Bonn-Miller et al. (2021, PLOS ONE) in 80 veterans showed no significant advantage of marijuana over placebo in PTSD. Neurobiological hypotheses indicate the potential of CBD as an adjunct to exposure therapy, but large RCTs are lacking. PTSD requires specialized treatment: SSRIs, cognitive-behavioral therapy with exposure elements, or EMDR.

Can CBD help with insomnia?

The retrospective study by Shannon et al. (2019, The Permanente Journal) indicated improvement in sleep in 66.7% of 72 patients after one month of supplementation with 25 mg of CBD daily. The mechanism is likely indirect, through the reduction of anxiety preceding sleep onset. There is a lack of large RCTs on primary insomnia. Sleep hygiene and CBT-I therapy remain first-line treatments.

Can I combine CBD with antidepressants?

CBD is metabolized by cytochrome P450 enzymes (CYP3A4, CYP2C19), the same ones that break down many SSRIs and other psychiatric medications. This may alter the concentration of medications in the blood. Consultation with a psychiatrist or clinical pharmacist before combining is necessary. Do not discontinue medications without consultation.

Is THC legal in Poland in 2026?

According to the Act of July 29, 2005, on counteracting drug addiction, possession and trade of marijuana with THC above 0.3% remain illegal, with a penalty of up to 3 years imprisonment. The exception is the fulfillment of an Rpw prescription for medical marijuana issued by a doctor. CBD products with THC below 0.3% are legal.

Can I smoke CBD flowers to calm my nerves?

CBD hemp flowers with THC below 0.3% are legally available in Poland, most often for aromatherapy or collectible purposes. Smoking is not a recommended method of use due to pyrolysis products harmful to the respiratory system. Sublingual oils or vaporization at low temperatures are safer.

Does CBD cause addiction?

According to the WHO ECDD critical report (2018), CBD does not show addictive potential or significant adverse effects at doses up to 1500 mg daily in healthy volunteers ([WHO ECDD CBD Critical Review, 2018](https://www.who.int/publications/i/item/who-ecdd-40-cbd-critical-review)). This distinguishes CBD from THC, which has documented addictive potential (cannabis use disorder develops in about 9% of users).

What dose of CBD should I start with?

The recommended approach is to start low, go slow: begin with 10-25 mg of CBD daily, increase by 5-10 mg every 5-7 days, observing reactions and side effects (mainly drowsiness, dry mouth, fatigue). Doses studied in anxiety RCTs were 300-600 mg at a time, significantly more than typical supplemental doses.

Can a doctor refuse to issue an Rpw prescription?

Yes. A doctor is not obligated to issue a prescription for medical marijuana. The decision is individual, based on risk assessment, indications, and therapeutic alternatives. A patient has the right to seek consultation from another specialist, but does not have the right to "demand" a prescription.

Summary: a balanced approach to cannabis and mental health

Cannabis is neither a miracle cure nor a clear poison for the psyche. According to current data: CBD has the best-documented anxiolytic effect (Bergamaschi 2011, Linares 2018) and supportive effects in schizophrenia (McGuire 2018), although research doses are high. THC carries real risks of psychosis in predisposed individuals (Marconi 2016) and depression in youth (Gobbi 2019). In insomnia and PTSD, the data is promising but incomplete.

The Polish legal context remains strict, although since 2017, medical marijuana on Rpw prescription has been available. CBD with THC below 0.3% is legal, but the quality of products on the market is varied. The most important principles are: consultation with a psychiatrist for mental health disorders, low initial dose, no self-discontinuation of medications, quality control of the product.

If you are struggling with anxiety, depression, or suicidal thoughts, do not try to solve this on your own. Call 116 123 or 800 70 22 22. Professional help is available, free of charge, and accessible.

Disclaimer: This article is for informational and educational purposes only. It does not constitute medical advice, diagnosis, or treatment recommendations. In case of mental health disorders, consultation with a psychiatrist is necessary. Do not discontinue psychiatric medications (SSRIs, benzodiazepines, antipsychotics, mood stabilizers) on your own. In Poland, possession and trade of marijuana with THC above 0.3% are illegal (Act of July 29, 2005, on counteracting drug addiction), except for Rpw prescriptions. CBD with THC below 0.3% is legal. In a mental crisis, call: 116 123 (adult helpline) or 800 70 22 22 (24/7 Support Center). The author and publisher are not responsible for decisions made based on this text.