“Lover’s Speed” – How does MDMA affect time perception?

MDMA (3,4-Methylendioxy-N-methylamphetamin) is a synthetic chemical, and is classified as an illegal drug in most countries of the world, including the Netherlands. However, in 1997, approximately two percent of Dutch respondents still used the drug at least once in their lives. By 2019, this increased to almost nine percent (Statista, 2021). The Netherlands is among the largest illegal MDMA manufacturers worldwide (Schaart, 2019). MDMA, which is mostly used as a party drug and is colloquially called ‘Molly’, ‘Ecstacy’ or ‘Lover’s Speed’, acts as both a stimulant and a psychedelic. It produces an energizing effect, enhanced enjoyment of tactile experiences, and crucially, distortions in time and perception. It reduces inhibition and promotes euphoria, feelings of closeness, empathy, and sexuality. Concurrently, MDMA can cause blurred vision, muscle tension, ataxia and anxiety, amongst other acute symptoms. Importantly, MDMA also exhibits risks including addiction, psychosis, dehydration, damage to the liver and kidney, or even heart failure (National Institute of Health, 2021).

Although MDMA is a drug that holds dangers, the distortion in time perception is a curious side effect which is shared with other stimulant drugs including alcohol, caffeine and cocaine. How can stimulants affect time perception, however? There are two logical explanations that come to mind. Either the activities that we perform whilst intoxicated influence how we perceive time, perhaps by averting our attention away from time. As already noted, our perception of time is influenced by our emotions and the activities we engage in. Maybe MDMA acts on our emotions, and we lose track of time when we feel good? The holiday paradox illustrates this well, where airport waits feel long because we are bored, but short once look back on them because close to nothing happened during this wait. Paradoxically, the exciting day trip at our holiday destination feels like it’s flying by while we are on it, but then seems like a long time when we look back at all the things we have experienced (Buonomano, 2018). Another explanation could be that the drugs alter the speed of our internal clock by changing the way in which the brain monitors time (Meck, 1983). 

In order to understand the distortion of time perception in the intoxicated brain, let’s first examine how our brain’s internal clock works when we are sober. Unsurprisingly to psychologists, no singular area in the brain controls time perception – it seems to be a distributed phenomenon across large networks (Fontes et al., 2016). including, the prefrontal cortex, cerebellum and basal ganglia (Apaydin et al., 2018). The cerebellum is responsible for implicit and precise representations of time, temporal reproductions and our internal clock, which is in charge of discriminating between different temporal intervals. The basal ganglia implicitly keeps track of time relative to regular rhythmic intervals. The prefrontal cortex is explicitly, or consciously, supervising time.

Next to serotonin and noradrenaline, MDMA pivotally increases the activity of dopamine (Mustafa & Mohamad, 2019) in the mentioned brain areas. Dopamine is best known to produce increased energy and activity and act in the reward system to reinforce behaviors through pleasure. Interestingly, research has found dopamine to be most closely linked to time perception compared to other neurotransmitters. This chemical link to time perception was demonstrated in multiple studies, including one which found that people with disorders linked to dopamine defects such as Parkinson’s disease have problems tracking time (Buonomano, 2018). Surprisingly, across studies, increased levels of dopamine are linked to both overestimations and underestimations of time. For example, in one study, subjects were given drugs that increase dopamine, and then asked to indicate when one minute had passed, without using a clock. Under the influence of the stimulant, subjects indicated that the minute was up before it actually was, thus representing an overestimation of time (Huberman, 2021). Increased dopamine is also associated with increased blinking: people who blink more have higher dopamine levels and the administration of dopaminergic drugs increases blinking. Interestingly, a recent study even found that time subjectively dialiates after blinking, thus, leading to an overestimation of passed time (Terhune, Sullivan & Simola, 2016). Critically, these findings are not in line with the underestimated time durations under the influence of stimulants reported from MDMA users, and other stimulant users.

In a recent experiment the opposite was found, namely that increased dopamine is related to underestimations of time durations (Soares, Atallah & Paton, 2016). In this study, researchers trained mice to perform a timing task in which the mice were listening to two tones and then indicated if the delay between the tones was shorter or longer than 1.5 seconds. The mice were incentivised to give correct guesses of delay length with food. Additionally, they measured dopamine activity in the substantia nigra, an area strongly connected with the basal ganglia. The researchers found that mice were more likely to judge an interval as short when the dopamine activity was high. In a second experiment, they activated or silenced dopaminergic neurons using optogenetics. Again, boosting dopamine levels led to underestimations of time durations in mice. In the light of this research, time perception is altered due to changes of the brain’s internal clock, or in other words, how the brain monitors time.

The idea that time perception can be influenced by the activities we engage in, and critically, how much of our experiences we encode as memories, has also found support. A literature review by Roberts et al. (2018) found that MDMA affects memory due to disruptions of hippocampal function, mainly through the alterations in dopaminergic and NMDA receptors. In mice, memory deficits resulting from MDMA exposure were explained by the reduction in dopaminergic markers in the substantia nigra over time. Another study reported that acute MDMA diminished entire hippocampal functions. The hippocampus is the main short-term memory store and enables their transition to long-term memories. If MDMA disrupts memory formation, then this could also explain the perception that less time has passed when looking at time retrospectively, because only few memories were encoded – think of the holiday paradox. 

As for other brain chemicals affected by MDMA, their relation to time perception is even more unclear than dopamine. Noradrenaline, which increases heart rate and blood pressure and is related to arousal. Serotonin influences mood, appetite, sleep, and triggers hormones that affect sexual arousal and trust. The release of large amounts of serotonin likely causes the emotional closeness, elevated mood, and empathy felt by those who use MDMA. These positive valence of emotions and the high arousal felt during MDMA highs could be considered to lead to the perception that time flies, too: in one study, participants in a positive-high arousal state perceived time passing quicker than participants that were in negative-valence and low arousal states (Choi, Lee & Lee, 2021). 

In sum, the secret of MDMA’s distortion of time perception seems to lie in its effects on dopaminergic pathways. However, the current state of research provides incoherent evidence about when dopamine speeds time up or slows time down, and research on serotonin and noradrenaline provides paradoxical evidence too. Making sense of studies on time perception under the influence of psychoactive drugs can be challenging and controversial due to their interconnected neurophysiological effects including hunger, anxiety and motor activity which may affect animals motivation to participate in a task. Ethical considerations concerning drug-illegality limit the administration of drugs such as MDMA in experiments involving humans. Alcohol and caffeine, stimulants which also affect the dopaminergic pathways, may give insights into dopamine-related time perception. How exactly the brain monitors time is a fruitful avenue for future research. For now, it remains to hold many mysteries for us. <<