The Dark Side of Dreams

Although humans have been asking “why do we dream?” for centuries, science hasn’t reached a consensus. When it comes to dreams, we’re still largely in the dark. Our understanding of nightmares is even dimmer, and our grasp on recurring nightmares is the faintest of all. But that hasn’t stopped scientists from proposing various theories over the years. Let’s explore some of the most common potential causes of recurring nightmares, both internal and external, and try to get a comprehensive overview of this mysterious phenomenon. 

Looking at external causes like stress, trauma, and sleep disruptions, it’s no secret that the things we experience during the day can seep into our dreams at night. If you’ve had a particularly stressful day at work, for example, you might find yourself dreaming about getting fired or an angry boss. When we’re under a lot of stress, our brains struggle to process all the information we’ve taken in during the day. This causes a backlog of thoughts and emotions that get released in the form of vivid or disturbing dreams (Levin & Nielsen, 2007). It is also possible that our minds use nightmares as a means to process and cope with stress. Kundermann et al. (2017) reviewed what we know about nightmares and argued that generally, dreaming helps us consolidate memories and emotions, and recurring nightmares may indicate that our mind is repeatedly trying to work through a particular issue or stressor. Perhaps there is merit in both these theories. In either case, we’ve indeed found that the more stressed someone is, the more likely it is that they experience intense recurring nightmares (Kwok et al., 2016; Pesant & Zadra, 2006). 

Another culprit is trauma. People who have experienced a traumatic event in the past, such as a car accident or assault, may find themselves reliving that experience over and over again in their dreams. In fact, recurring nightmares are in the diagnostic criteria for PTSD, with over half of PTSD patients experiencing chronic nightmares (APA, 2013). Research also suggests that the content of these nightmares provides insights into the real, waking psychological issues that a person may be struggling with (Krakow et al., 2010). 

Sleep disruptions also cause us to wake up frequently during the night, leading to ‘sleep fragmentation’, where our natural sleep cycle is interrupted and we spend a lot more time in the rapid eye movement (REM) stage of sleep, which is when most dreaming occurs, resulting in more vivid, intense and emotionally charged dreams, including recurring nightmares (Stickgold et al., 2001). Various sleep disorders also commonly lead to recurring nightmares. For instance, in sleep apnea, which involves oxygen deprivation, feelings of suffocation or choking occur which may then be incorporated into nightmares – one may dream that they’re drowning or being suffocated by a heavy weight on their chest (Krakow et al., 2000).

Recurring nightmares can also stem from within, as a result of things  like threat rehearsal, unmet psychological needs, and personality. 

According to a theory introduced by dream researcher Dylan Selterman, recurring dreams can be a form of “threat rehearsal” (Selterman, 2021). They allow us to practice responses to potential waking threats in the safe and controlled environment within our mind, potentially increasing our ability to respond effectively in the case of encountering these threats in real life. One study published in the journal Dreaming found that people who reported recurring nightmares about interpersonal conflicts also reported higher levels of coping strategies in waking life (Yu & Zhi, 2017). It’s also been found that individuals who report danger-related recurring nightmares had better problem-solving abilities (Rhudy & Davis, 2007).

Recurring nightmares can also result from unfilled psychological needs like autonomy, competence and relatedness, according to Weinstein et al. (2018). This happens because unfulfilled needs trigger negative emotions like anxiety and insecurity, which then influence dream content. For example, a lack of autonomy during the day may activate feelings of helplessness or vulnerability, which can then appear in recurring nightmares in the form of being trapped and powerless.

Finally, could possessing certain personality traits influence one’s likelihood of experiencing recurring nightmares? Longitudinal research by Ruiz-Cordell and Jaffe (2016) indicates that it could indeed! Individuals high in neuroticism tend to experience more negative emotions, and experience them more intensely. They are more likely to have nightmares related to these emotions. And individuals who are high in openness to experience have rich and active imaginations, which can lead to more vivid dreams. So, their nightmares are more intense. 

As is often the case in psychology, these internal and external factors never operate in isolation. They may compound or reinforce each other, making the nightmares all the more haunting. For example, a neurotic person who experiences chronic stress is susceptible to nightmares, which could lead to sleep deprivation and further exacerbate their stress, creating a vicious cycle. 

Recurring nightmares have long been a source of intrigue and mystery, and despite extensive research, there is still much to uncover about this phenomenon. From external factors such as stress, trauma and sleep disruptions to internal causes like threat rehearsals, unmet psychological needs, and personality traits, recurring nightmares are complex and can evidently arise from a variety of sources. As we continue to explore the science behind them, one thing remains certain: recurring nightmares are a testament to the fascinating, and sometimes terrifying, power of the human mind.