ow are your dreams these days? If they’re unusually vivid and bizarre, you’re not alone. Your housemates might not be interested in the content, but that’s OK, the internet is, with social media and online forums awash with people outlining in detail their “lockdown dreams”. Some of these are clearly symbolic of our current daytime fears – difficulty breathing, trying to scrub bugs off our bodies, being trapped. But the virus and its consequences don’t always take centre stage. Some people’s dreams have entirely different distressing themes; others are finding that they are simply dreaming more, and that the dreams are more fantastical. It’s a strange irony that as our waking hours become more monotonous, our nighttime lives seem more varied. Scientifically, what makes our dreams more or less graphic is essentially mysterious. Research suggests that the more in tune we are with our feelings during our waking hours, the more colourful (literally) and memorable are our dreams. Medications that tinker with adrenaline and noradrenaline – two neurotransmitters that mediate our levels of arousal and our response to stress – can have dramatic effects on dreams. Many patients taking beta blockers, which interfere with these neurotransmitters, notice intense new dreams or nightmares. Other drugs that interfere with noradrenaline are used, along with therapy, to treat severe nightmares. Under lockdown we have fewer opportunities to use our normal coping strategies. Are the anxieties of our collective subconscious creeping out for unfettered play at night? A more prosaic factor may be the disruption of our usual routines. It’s probably not too controversial to say that we might be finding time for a little more morning rumination during the lockdown (before, ahem, leaping out of bed to work a productive eight-hour day from home). Disrupted or altered sleep is commonly reported after any kind of stress, from perceived social sleights to natural disasters. And we don’t have to be directly affected by events for them to start weighing on our subconscious. In 1986, the Nasa Challenger space shuttle exploded in footage that was widely viewed. Interviews several weeks later showed that even among children living on the west coast of the US, in the wrong timezone to have seen the accident live, and without local personal connections, a quarter experienced repeated shuttle-related dreams. Reassuringly, 14 months after the explosion, these dreams, and other anxiety symptoms, had substantially reduced. To be clear, this is a different phenomenon from the chronic nightmares of post-traumatic stress disorder. The puzzle here is why so many of us are having such realistic and memorable dreams as this crisis develops. Scientists have tried to capture how national trauma affects sleep quality. During the first Gulf war, in 1991, nighttime missile attacks on Israel came with little warning. Sleeping was dangerous. Unsurprisingly, telephone surveys found high rates of reported sleep problems. But when researchers followed up by actually recording sleep, they couldn’t find evidence of decreased sleep quality during the conflict. The immediate effects of stress on sleep seem to be subtle, not easily captured by monitoring our brain waves or nighttime movement. What you remember on waking is a faded facsimile of the dreams you had. Dreams, particularly vivid dreams, usually happen during rapid eye movement (REM) sleep. It’s a ghoulish sleep stage we shift in and out of during the night. In terms of the brain’s electrical activity, it has a lot in common with being awake. If you are purposely woken during REM sleep – a favoured trick of sleep science laboratories – you are more likely to recall your dreams. We are still in the early stages of understanding sleep, and we know even less about the science of dreams. They are as slippery to study as they are for us to understand individually, sneaking off as we wake. We think that dreams help us to cope with stress and process emotion, but this is a tricky idea to test scientifically: we don’t have a method to manipulate our dreams without affecting other aspects of sleep. When something is difficult to study in humans, neuroscientists often turn to animals. You can’t ask a rat whether it dreams of electric sheep, but you can record how much REM sleep it’s getting. Rat studies show that the effects of stress on REM sleep depend on the amygdala – a small structure buried deep in the brain that directs the emotional response to our external world. The amygdala is packed with receptors for stress hormones. What really gets our stress system going are situations that feel unpredictable and uncontrollable. And it’s loss of control that might be important for our dreams, too. In mice, short bursts of escapable stress led to increased duration of REM sleep; if the stress was of the same intensity, but inescapable, REM sleep was decreased. Coronavirus is causing financial hardship, social isolation, loss of our normal roles, and, for some, loss of loved ones. These stresses are real and present, others are feared or existential. Uncertainty and unpredictability dominate our experience. So far so normal, in the sweep of human history. What’s different about the current crisis is the additional stress of social distancing. Our bizarre dreams are the tip of the psychological iceberg. We are now, like it or not, taking part in a giant experiment into the effects of increased stress in tandem with dramatically reduced social contact. This is an opportunity to learn about how we respond to this dual assault, what factors affect how this impacts different people, and what helps us through. Stress and social isolation were problems before coronavirus bared its spikes – this crisis could transform our knowledge of how to help those who may still face social isolation when the lockdown lifts. Research efforts are under way. For example, the public can take part in the King’s College Repeated Assessment of Mental Health in Pandemics study. As for these vivid lockdown dreams, for most of us they will pass. In the meantime, normal sleep hygiene rules apply. That also means no refreshing that live coronavirus feed just before bedtime – although I’m still working on that at my end. • Dr Mary-Ellen Lynall is a neuroscientist and psychiatrist at the University of Cambridge