## 4 Discussion  
The purpose of the present systematic review was to examine extant research investigating the efficacy of nonpharmacogical interventions for TDs in children and adolescents. Since the literature lacks of explicit evidence on the potential impact of different types of tS, CTD, and PTD on treatment efficacy [7], the focus was placed on the therapeutic effects of nonpharmacogical interventions on tic severity. The differential treatment effect on motor tics, vocal/phonic tics, and level of impairment was explored. Overall, findings confirmed the efficacy of psychosocial and behavioral treatments, which could be considered as first-line interventions for pediatric patients with TDs [17; 35]. Among the different behavioral interventions, the studies primarily focused on HRT [30], ERP [21; 22], an intense form of ERP called TYT [29], and CBIT [15; 18; 19; 20; 31]. The effectiveness of HRT [7; 35; 36; 37; 11; 12; 38; 39], ERP [7; 35; 37; 36; 38], and CBIT [11; 12; 36; 38; 41] has been extensively examined and validated in the scientific literature, in both recent and prior studies. In addition, the present review provided support to the effectiveness of behavioral interventions when administered online [18; 19; 20; 21]. The implementation of telehealth interventions, such as the ICBIT program, has many advantages: not only facilitating a continuous and uninterrupted treatment [20], but also enhancing the accessibility to care [20; 21], par ticularly for children who are unable to access any form of face-to-face therapy for tics [22], and therefore, reaching a broader population of youth [21]. Finally, online behavioral therapies for tics may be optimally effective as a primary interventions with nonresponders or partial responders who can subsequently be treated with more intensive face-to-face therapy [22]. An interesting result was that in six out of nine studies [15; 19; 20; 29; 30; 31] exploring motor tics, vocal tics, and tic-related impairment, behavioral interventions were generally effective in reducing motor tics, with effect sizes ranging from 0.22 to 1.07. This finding is consistent with a previous review and meta-analysis [42] conducted on adults, which showed that nonpharmacogical therapy is effective, compared to the control group, especially for motor tics. The CBIT-VoIP [19] appeared to be the most effective treatment in reducing motor tics (1.07), possibly related to the inclusion of techniques such as diaphragmatic breathing and progressive muscle relaxation in the online version. Conversely, the sole implementation of HRT [30] appears to show only a modest effect on motor tic reduction, in accordance with previous studies conducted on adults [42]. Therefore, it seems that a more comprehensive and multimodal intervention--incorporating a combination of behavioral, educational, and stress management techniques--may be more effective in reducing motor tics. Moreover, group-based CBIT interventions focusing on tic reduction were associated to more lasting effects [31], suggesting a role of social support in motor tics improvement. However, it should also be considered that children with behavioral difficulties such as aggressive and attention problems benefited less from group interventions [29; 30; 31]. Greater variability in the effectiveness of behavioral treatments has been observed in the reduction of vocal tics, with effect sizes ranging from \(-0.28\) to \(1.32\). Notably, three studies reported a lower effectiveness on vocal tics when compared to motor tics [19; 20; 30]. The authors hypothesized that this result could be related to the intervention protocol, focusing on a few tics which were experienced by children as the most distressing [30; 43]. Because of this procedure, in fact, the youths often preferred to work on motor tics (e.g., in the study by [PERSON] and colleagues [31], where the authors noted that 76.5% of participants primarily chose to focus on their motor tics).