Time may fly when you're having fun, but it can feel as though it's screeching to a halt when you're depressed.
People with depression actually perceive time as going by more slowly than people who are not depressed, according to a review of studies published in the Journal of Affective Disorders in January.
To investigate the link between depression and time perception, German researchers analyzed data from 16 previous studies on more than 800 depressed and non-depressed people. Most of the studies assessed time perception by asking participants to gauge the length of time that they had engaged in different activities, such as watching a short film or pressing a button. The analysis revealed that people with depression reported a slower subjective experience of time -- they often felt as though time was slowly dragging by.
It's a phenomenon that's been explored fairly extensively in other research, although the mechanism by which depression slows time perception is still not fully understood.
One study suggested that this slower perception of time might be based in the physiology of depression. The research, published in the journal Behavioral Processes in 2009, showed that depression may cause a slowing down of the individual's internal clock -- possibly caused by a general slowing down of motor behavior.
"The feeling that time is passing slowly may be based on an awareness of the slowing down of the internal clock and/or an awareness of changes in the rhythm of executive functions in comparison with time in the outside world," the study's authors write.
Another reason for the difference in time perception may be the way that attention is regulated differently in depression patients compared to non-depressed individuals.
People with depression, a disorder characterized by obsessive negative thoughts and rumination, may struggle to give their full attention to the present moment. This can make it difficult to get absorbed in an activity, entering that "flow" state of consciousness that can make you feel as if time is flying by.
Mindfulness-based therapies -- which help patients to cultivate a focused, non-judgmental awareness on the present moment -- may be particularly effective for combatting a depressed perception of time, according to Dr. Steven Meyers, a clinical psychologist and professor of psychology at Roosevelt University in Chicago.
"Attention is often affected in people who experience stress or depression -- their minds drift off as they ruminate about their problems, which can further worsen their situations," Meyers told The Huffington Post in a previous interview. "[Time perception] research highlights yet another benefit of mindfulness: It allows us to better appreciate the events and people around ourselves rather than feeling like we're living our days in a blur."