Personal communication devices can both increase and decrease personal productivity. They may make people more efficient by speeding up calculations and work, but they can also be a distraction that decreases focus on the actual work. Having permanent contact through devices can have psychological consequences as well. It may shorten attention spans, encourage instant gratification and self-centeredness in young users. Addiction to messaging and emailing displays symptoms like withdrawal and negative impacts, and could be considered a form of mental illness.