Anxious when your smartphone's battery runs out? Panicked when you leave the device at home? You could be nomophobic and you're not alone.Researchers at Iowa State University, in the US, have come up with a test for measuring the severity of your nomophobia (no-mobile-phone-phobia).They ask smartphone users to answer 20 questions relating to their anxiety when they lose connectivity, run out of data or battery power, or are without their device.To develop the test, Iowa State's Caglar Yildirim and associate professor Ana-Paula Correia interviewed nine students about their smartphone habits.They then identified four prime causes of nomophobia: not being able to text and call friends and family, not being able to access social networks, not being able to search for information online and losing the convenience of having a smartphone.In an interview with USA Today, Yildirim said dependency on smartphones could affect mental and psychological wellbeing.The principal psychologist at Chris Hani-Baragwanath Academic Hospital, Johannesburg, Jasmin Kooverjee, said a user's psychological wellbeing was affected if a smartphone impaired the ability to function."For example, if you cannot function normally at home, at work or at school because of your phone," she said.Kooverjee said nomophobia could be on the rise."People cannot fathom living without their phone because it is their source of contact with the world. And for many people the fear of not having that contact is increasing."It could be parents worried that they are unable to take a call from their child's school if the child is sick; or it could be younger people, who are trying to meet up."Before cellphones, we would give a date, a time and a place for a meeting and make sure we were there. But now when people make plans they say: 'I'll call you when I am there'. And the fear is what will happen if I can't call?"Kooverjee advised people with severe nomophobia to get professional help."Anything limiting your ability to function means you need to get help. You need some form of intervention, such as psychotherapy by a clinical psychologist."The over-use of smartphones in social settings has led to the development of phone etiquette, especially around meals.In recent times, the Phone Stack game has been invented. This involves a group of friends who are dining out stacking their cellphones on the table in plain sight, face down.As the meal progresses, all the diners are likely to hear their phone notifying about something: SMSes, calls, tweets, Facebook.But you're not allowed to check your device.The first to succumb and pick up a phone pays the bill for all...