MIAMI (CBSMiami) -- Growing evidence shows lack of sleep is taking a larger toll on your mental health than originally thought.
A study released in the journal of Cognitive Therapy and Research found those who were sleep deprived lose some of their ability to be 'positive-minded' - something to notice since more than a third of Americans don't get enough sleep.
In general, we have a tendency to notice positive stimuli in our environment," said Dr. Ivan Vargas who led the study."We tend to focus on positive things more than anything else, but now we're seeing that sleep deprivation may reverse that bias."
While it may not sound serious, medical experts say the inability to think in a positive manner is a serious symptom of depression that, if left unaddressed, could be dangerous.
"If you don't get enough sleep, it reduces your ability to attend to positive things, which over time may confer risk for depression," said Vargas.
It's something to keep in mind when an estimated 16.1 million adults experienced a depressive episode in 2014.
The study also found those with a history of insomnia symptoms were less sensitive to the effects of sleep deprivation. This could be because they've developed coping methods to decrease the effects, researchers say.
Physically, lack of sleep over time could lead to heart disease, diabetes, or stroke among other conditions, according to the National Heart, Lung and Blood Institute.
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