Cannabis for sleep and anxiety: a careful look

Sleep problems and anxiety top the list of reasons New Zealanders turn to medicinal cannabis — in 2025, sleep or insomnia featured in around 72% of medicinal users and mental-health reasons in around 62%. Yet these are also areas where the evidence is more limited, and the risks more nuanced, than the popularity suggests. Here's a careful, sourced look.

Sleep and insomnia

The evidence for cannabis and sleep is limited and emerging, with an important wrinkle: any benefit appears to be driven by THC-containing products, while CBD-only products have shown no significant effect on sleep in the research. A 2025 meta-analysis found subjective sleep improved versus placebo, but mostly from THC products, and most studies were of poor quality.

There are real cautions:

• Tolerance. The sleep benefit of THC can fade over time as tolerance develops.
• REM disruption. THC can suppress REM (dreaming) sleep.
• Next-day grogginess is common, especially with oral products that last into the morning.
• Rebound insomnia can follow stopping after regular use.

So while some people find a THC-containing product helps them sleep, it's not a clean or risk-free solution, and the evidence base is thin. Good sleep hygiene and addressing underlying causes remain first-line.

Anxiety

Here the picture is limited and genuinely mixed, and the central paradox is that THC can worsen anxiety even as CBD may help it.

A 2024 review of 15 randomised trials found roughly 40% positive results and 60% negative. The positive signals tended to involve CBD — for example around 300 mg of CBD for performance anxiety. Strikingly, the relationship isn't linear: two trials found that a higher dose (600 mg of CBD) actually increased anxiety, suggesting an inverted-U dose-response where more is not better.

Meanwhile THC is a known anxiety risk — at higher doses or in vulnerable people it can provoke anxiety, panic and paranoia. This is why, for anxiety, prescribers typically favour CBD and minimise or avoid THC, and why the dose has to be got right rather than simply maximised.

A serious caution: psychosis risk

For anyone considering THC for mental-health symptoms, the psychosis risk deserves emphasis. The research supports a dose-response relationship: daily use is associated with higher psychosis risk, and high-potency THC with daily use roughly doubles the odds, with earlier onset. A personal or family history of psychosis or schizophrenia, and use in adolescence, markedly raise the risk. People with such a history are generally screened out, and THC should be approached with great caution where mental health is the concern.

What this means for patients

• Cannabis is not a first-line treatment for sleep or anxiety, and the evidence is limited.
• For anxiety, CBD — not THC — is the more sensible candidate, at a carefully chosen dose, since more isn't better and THC can backfire.
• For sleep, only THC-containing products have shown benefit, but with tolerance, grogginess and rebound to weigh against it.
• Address the basics first — sleep hygiene, therapy for anxiety (psychological treatments remain frontline), and underlying causes.
• Screen carefully for psychosis risk before any THC product.
• Set realistic expectations and trial with clear goals, willing to stop if it isn't clearly helping.

The interaction between sleep and anxiety

Sleep and anxiety are deeply intertwined — anxiety wrecks sleep, and poor sleep worsens anxiety — and many patients come to cannabis hoping to break that cycle. The difficulty is that the two problems can point toward opposite products. THC-containing products are the ones with any sleep signal, yet THC is precisely the cannabinoid that can worsen anxiety, while CBD (the better candidate for anxiety) hasn't shown a sleep benefit on its own. There's no neat single answer, which is part of why these conditions need careful, individualised prescribing rather than a one-size product. Treating the root cause — through therapy for anxiety, good sleep habits, and addressing medical contributors — often does more than any cannabinoid, and may make a low-dose trial more likely to help if one is pursued at all.

A word on dependence and tolerance

Both sleep and anxiety are conditions where people can drift into nightly, escalating use, so it's worth naming the risks. Tolerance to THC's sleep effect can build, nudging people to higher doses; stopping after regular use can bring rebound insomnia and a withdrawal syndrome (irritability, anxiety, disturbed sleep, vivid dreams). For anxiety in particular, leaning on a substance can crowd out the psychological approaches that have the strongest evidence. None of this is a reason for blanket avoidance, but it's a reason to use the lowest effective dose, review regularly, and not treat cannabis as an indefinite nightly habit by default.

The bottom line

Sleep and anxiety are exactly the conditions where enthusiasm runs ahead of evidence. Cannabis may help some people — CBD for anxiety, THC products for sleep — but the research is limited, the dose-response can be counterintuitive, and THC carries real risks of worsening anxiety and, in vulnerable people, triggering psychosis. Treat it as a carefully chosen, closely supervised option after first-line approaches, not a go-to remedy.

Last reviewed 19 October 2026 — education, not medical advice. Sources: 2024 anxiety RCT review (PMC11595441); 2025 sleep meta-analysis; Robinson et al. — psychosis risk.