*2.2. Instruments*

In the present study, we administered to participants some different scales: (1) the Gaming Motivation Scale (GAMS) developed by Lafreniére and coworkers [22], (2) the Assessment of Internet and Computer Game Addiction Scale (AICA-S; [29]), (3) the Center for Epidemiologic Studies Depression Scale (CES-D; [30]), and 4) the State-Trait Anxiety Inventory (STAI; [31]).

The GAMS was generated on the basis of Deci & Ryan's conceptual definitions of motivations [21]. The purpose of this scale was to investigate the reasons at the base of playing VG; participants were asked to respond to 18 items rated on a 7-point Likert scale (from 1 "do not agree at all", to 7 "very strongly agree") and bearing in mind a same basic question, i.e., "Why do you play to video games?". The scale allows to assess different type of motivations: intrinsic motivation (desire to perform an activity for itself), integrated regulation (first aspect of extrinsic motivation, that refers to engaging in an activity out of choice), identified regulation (second aspect of extrinsic motivation, when people engage in a behavior based on its perceived meaning or its relation to personal goals), introjected regulation (third aspect of extrinsic motivation, that refers to the regulation of behavior through internal pressures such as anxiety and guilt, implying partial internalization), external regulation (fourth aspect of extrinsic motivation, that refers to behavior regulated through external means such as rewards), and amotivation (similar to learned helplessness, that refers to the relative absence of motivation either intrinsic or extrinsic) [22]. GAMS was translated into Italian by two experienced researchers; the translation was then evaluated by two independent experts in experimental psychology. Finally, one translator (an English native speaker) back-translated the questionnaire from Italian to English. After this procedure, the Italian version of the scale (GAMS-it) was obtained. For the general structure of the scale, we maintained the original one and thus the order of the items is the same as in the validation study (see Reference [22]).

The Assessment of Internet and Computer Game Addiction Scale (AICA-S; [29]) is a self-report scale for the assessment of potentially pathological computer and game behavior. Fifteen items are relevant for clinical classification of computer game use behaviour (e.g., craving, tolerance, loss of control, unsuccessful attempts to cut back, and withdrawal). Previous studies on its psychometric properties yielded satisfying results concerning item characteristics, reliability and validity [32]. For the present study, AICA-S was used for determining the amount of hours of gaming and to identify the participants defined as "Heavy Gamers" (HG) and "Light Gamers" (LG). In particular, we took into consideration the answer to the fourth question of this scale ("How you long are you playing computer games?", with five response categories (1 = "less than one hour per week", 2 = "1–2 h", 3 = "2–4 h", 4 = "4–6 h" and 5 = "more than 6 h to week"): participant who responded "1" were included in LG group, instead the participant that responded "4" and "5" were included in HG group. With respect to the meaning of question 1, "computer games" were intended as all the types of games both those on online platforms and on home console. The Italian version of AICA-S has been developed by following the same procedure followed with GAMS [33].

The 20-item Center for Epidemiologic Studies Depression (CES-D; [30]) is frequently used to estimate the prevalence of depressive symptomatology in the general population. Respondents rated the frequency with which they have experienced particular depressive symptoms during the past week. Answers to each item range from 0 (less than 1 day) to 3 (5–7 days) and are summed to compute a total score. It measures a single depression factor, ranging from 0 to 60; scores of 16 or above are considered potentially pathological.

The State-Trait Anxiety Inventory (STAI; [31]) is a commonly used measure of trait and/or state anxiety all over the world. It can be used in both clinical settings and research. The most popular version (Form Y) has 20 items for assessing trait anxiety and 20 for state anxiety: In the present study, we used the trait version. All items are rated on a 4-point scale (e.g., from "Almost Never" to "Almost Always"). Higher scores indicate greater anxiety level.
