'Certainly patients with epilepsy, heart disease, migraines or Parkinson's disease may experience frequent recurrence of the same dream,' adds McKenna.ДЄnother scientific theory about the purpose of dreams is the concept that dreaming is a form of overnight therapy - so we deposit memories associated with strong emotions through REM sleep, but reduce some of the emotional content connected with them. Current research also indicates that changes in dream behaviour, and even dream content, may point to the onset of certain health issues before they show up in physical form, though conclusive evidence for this remains a source of conjecture. One study has shown a correlation between recurrent nightmares, cardiac symptoms and the menopause. 'And so people with this and some other neurological diseases will often have aggressive dreams of fighting or being attacked, and physically thrash, lash out, scream or swear.' 'The area of the brain that controls REM sleep is often damaged in conditions such as Parkinson's disease,' says Leschziner. Having vivid dreams every night that you recall (which may also involve physical actions or verbal outbursts) can be an indication that something is disrupting your dreaming sleep, such as sleep apnoea (which is worse during REM sleep), narcolepsy (when the switch that involves going in and out of sleep goes awry) or REM sleep behaviour disorder. However, there are certain changes in sleep and dream behaviours that are worth noting, which may indicate an underlying health concern. As well as being driven by individual psychological and physical components, our dreams may even be influenced by social and cultural factors.ДЇor example, one study has demonstrated that before colour television was introduced, only 15% of people dreamt in colour the findings showed that older people were likely to dream in black and white more often than the younger generation. The scope of 'normal' dream behaviour is surprisingly broad. GP Dr Pixie McKenna, spokesperson for Dreams, comments: 'Studies have shown that dreams are linked to learning and repair, and consolidating the experiences, skills and encounters we have had during the previous days.'Дr Guy Leschziner, consultant neurologist at the Sleep Centre, London Bridge Hospital, part of HCA UK, is in agreement and adds, 'it's about refining the deposition of memories.'

From a neurological perspective, there are many theories as to why dreaming is crucial to the sleep process.

Does dreaming mean deep sleep