AS MANY as one in seven of us could be suffering from a disorder known as 'confusion arousal' or sleep drunkenness, causing forgetfulness, disorientation and even violent behaviour when individuals are suddenly woken up.
Unlike regular morning tiredness, episodes of sleep drunkenness are infrequent but sometimes extreme, inducing personality change in the sufferer.
A new study published in the journal Neurology reports that 15 per cent of US adults suffer from the disorder.
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More than 19,000 individuals were surveyed, with the researchers finding individuals who suffered from sleep disorders were most likely to report episodes of sleep drunkenness (70.8 per cent), followed by individuals with mental disorders such as bipolar (37.4 per cent) and those who used medication, especially antidepressants (31.3 per cent).
"These episodes of confused awakening have not gotten much attention, but given that they occur at a high rate in the general population, more research should be done on when they occur and whether they can be treated," lead author Dr Maurice Ohayon of Stanford University said in a statement.
"People with sleep disorders or mental health issues should also be aware that they may be at greater risk of these episodes."
Previous studies have shown these states are most likely to affect younger people (17 per cent of children under the age of 13 experience it) but if adults find themselves suffering from these episodes it could be linked to a more serious, underlying problem.