“…Comorbid symptoms have included alcohol and substance use [47,48,51,65,66,71,74,82,86], proneness for problem behaviours [82], depression [48,50,67,68,78,81,83,87,124], suicidal ideation [124][105], ADHD [67,79,157], social phobia and phobic anxiety [79,84,87], schizophrenia, obsessive-compulsive disorder [67], psychoticism [71], and antisocial/aggressive behaviours [48,72,79,80,87]. Finally, a number of psychosomatic problems have been linked to problematic Internet use, such as a poor health condition, excessive daytime sleepiness [66], lack of energy, physiological dysfunction, weakened immunity [63], obesity, and poor vision [49].…”