It theorises that excessive worrying (regarded as unintentional misuse of the imagination) arouses the autonomic nervous system, which increases the need to dream during REM sleep.
[clarification needed] French scientist Michel Jouvet suggested that REM sleep is concerned with programming the central nervous system to carry out instinctive behaviours.
[6][7] William Dement and colleagues discovered that the amount of REM sleep a foetus or newborn has depends on how mature an animal is at birth.
Dreaming takes up a large amount of the brain’s energy, as the PGO spikes are continually firing, so depressed people tend to wake early but exhausted and lacking in motivation, setting the scene for more worry and distress the following day.
While the theory has widely been validated anecdotally, through people’s personal experience, it is not able to be put to rigorous scientific testing, as interpretations of dream events are necessarily subjective.