Sleep impacts a number of different physiological, hormonal and chemical processes in the brain. We generally assume that better sleep quality and duration can improve a number of conditions, but many research studies are showing that the relationship between sleep and depression is much more complicated. These studies found that sleep deprivation can be used for an immediate and drastic improvement in mood and relief from depressive symptoms in more than 50% of individuals with depression, including individuals with concomitant disorders, such as schizophrenia and bipolar disorder. The major downside is that this relief is only temporary and most patients relapse into depression after the first night of sleep, or even after just a nap. Researchers have been able to reduce the impact of this relapse by combining sleep deprivation with antidepressant medication in some individuals. Sleep deprivation also leads to an improvement in sleep continuity, which could be especially beneficial in individuals with both depression and intense insomnia. It has shown to have the strongest response in individuals with lower mood states in the morning and higher in the afternoons. More research is needed to better identify who will respond to sleep deprivation, as well as what medications are most successful in preventing the next day depressive relapse. We hope this will lead to new insight into the mechanisms that contribute to depression, as some antidepressants work on similar pathways and suppress REM sleep.