Objectives:
Internet Addiction Disorder can be defined as “the inability of individuals to control their internet use, resulting in marked distress and/or functional impairment in daily life.” It carries the same social aftermath of impulse control and substance misuse disorders such as loss of control, craving and withdrawal symptoms. Aim: In this paper, we aimed to assess the prevalence of IAD in an Italian sample of high-school students. We also explored the relationship between Social Phobia and IAD diagnosis; lastly, we investigated the association between IAD and substance misuse.

Methods:
The research was conducted in accordance with the Helsinki Declaration. Assessments administered in this study consisted of three parts: 1) collecting information about general and personal data of the subjects; 2) the Internet Addiction questionnaire proposed by Ko, composed by 9 different areas; 3) the Social Anxiety Spectrum Self-Report (SHY-SR) Lifetime Questionnaire.

Results:
19 of 402 subjects (i.e. 4.7% of the sample) fulfilled the diagnostic criteria for IAD, showing a slight predominance of males. 10.9% of subjects met diagnostic criteria for a Social Phobia Spectrum disorder. Six IAD subjects (31.8%) were also diagnosed with a social phobia spectrum condition. Within the group of students diagnosed with IAD, 4 (21.05%) subjects reported current or past use of drugs.

Conclusions:
Our results suggest that there is a sizable population of youth already showing or at risk of developing some kind of problematic relationship with the web. Social Anxiety Disorder seems to be both a risk factor and a frequent co-morbid disorder of internet misuse. Further studies along with shared diagnostic criteria and tools will facilitate research on treatments for these rapidly expanding and disabling conditions.