Smartphones can link their users to the world with the swipe of a finger, but research has also linked smartphones to distraction, anxiety and difficulty sleeping.

A study released by Harvard Business School showed turning off cellphones for at least one evening a week could lead to an increase in happiness and better performance at work. The three-year study found employees of the Boston Consulting Group who took one night a week off from cellphones were more productive and happier overall.

Other research has shown that blue light — emitted from devices like iPhones — suppresses melatonin, which is necessary for sleep or dreams, said Rubin Naiman, a sleep specialist and clinical assistant professor of medicine at the UA Center for Integrative Medicine.

In dark places the brain produces more melatonin, which helps an individual sleep. The light that comes from the iPhone sends a message to the brain telling it that it’s daytime, Naiman added.

When a person does not get enough sleep, effects include an elevated heart rate, increased anxiety and difficulty getting to sleep, according to Naiman.

“The cellphone is an automatic link to the waking life and we cling to it into the night and evening, and many people literally sleep with their iPhone,” Naiman said. “It becomes an appendage and it doesn’t allow us to fully surrender and let go to sleep and dreams.”

Naiman creates models for treating sleep and dream disorders and teaches people how to manage their energy throughout the day.

“A lot of college students have a lot of difficulty sleeping and one of the main reasons is that they don’t know when to put the brakes on,” Naiman said. “That includes letting go of the cellphone and turning everything off.”

Additionally, constant use of cellphones can simply serve as an annoyance to friends or even prove a dangerous distraction, which has resulted in a Tucson ordinance prohibiting texting while driving, which went into effect on Sunday. The ordinance prohibits drivers from sending or reading messages from a wireless communication device, and violation results in a $100 fine, or $250 if an accident is caused while texting and driving.

A study from the University of Utah has also proven that driving while using a cellphone can be as dangerous as driving with a .08 percent blood alcohol concentration.

“I see people cross the Speedway and Campbell intersection and they don’t look up from their cellphones,” said William Cornell, a sociology senior. “I don’t see why people can’t just take the time to stop and finish a text, or wait until they’re done with whatever they’re doing.”