**2. Emotional induction experiment**

disorder (IGD) may indicate an immediate emotional reaction [35]. The possible reasons why people addicted to online game were coping with negative emotions and stress, having entertainment, empowerment, mastery, control, excitement, and challenge [36]. The psychological

Concerning the physiological syndrome of IA, the autonomic nervous responses of highrisk IA (HIA) abusers was studied. The blood volume pulse and respiratory response of HIA abusers would increase, but peripheral temperature and skin conductance would decrease [22]. Heart rate variability (HRV) is one index of autonomic nervous system (ANS) activity. The high frequency percentage acquired from HRV of HIA abusers was lower, but the low frequency percentage of HIA abusers was higher than that of LIA abusers [37]. The results showed that the sympathetic nervous activities of HIA abusers were stronger, and the parasympathetic nervous activities were weaker than that of LIA

Emotion conveys psychological (subjective) and physiological (objective) information, and can be observed and assessed through psychological methods such as self-reports, interviews, questionnaires, and through physiological reactions such as the heart rate, respiration, facial expression, and particularly ANS activities [38]. The ANS which contains the sympathetic nervous system and parasympathetic nervous system, which has antagonistic effects, plays an important role in regulation of physiological reactions and emotions. The emotion-related responses derived from ANS are cardiovascular responses, respiratory responses, and electrodermal responses. These responses usually cannot be manipulated consciously [38–41], and can be measured using noninvasive methods. For example, heart rate variability (HRV) and respiratory sinus arrhythmia (RSA) acquired from electrocardiography (ECG), a noninvasive physiological signal, was a widely adopted index of the regulation of ANS activities. HRV presents the regulation of sympathetic activity and parasympathetic activity, and RSA

Emotion and feelings are the psychological hooks of addiction.

People with IA were reported bad scores on emotional intelligence tests.

Oktuğ [34] Excessive internet users were indicated poorer intimacy, and worse ability to express positive and

Ko and Yen [35] Withdrawal symptoms of internet gaming disorder (IGD) may indicate an immediate emotional

Brand et al. [14] Urge for mood regulation is an important factor within the development of Internet-use disorders

Petry et al. [21] DSM-V: playing games to escape from or forget about real-life problems or relieve negative

Oktan [31] Emotion management skills were meaningful predictors of IA.

negative emotions than others.

syndromes regarding emotion of IA are listed in **Table 2**.

(low-risk IA) abusers.

106 Drug Addiction

**Author Content**

Young [3] Emotion can be used to assess IA.

reaction.

emotional states.

**Table 2.** Psychological syndrome (emotion) of IA.

Peele (1991) in Young [3]

Parker et al. [32] Far et al. [33]

Emotional induction experiments using several emotional induction materials were conducted. The psychological characters were obtained using self-reports and questionnaires, and physiological signals were collected using respiratory belts and ECG. The relationship and differences in respiration between people with IA and people without IA, RSA, and HRV were tested, and the regulation of the parasympathetic activity in emotional states was discussed.
