## 4 Discussion  
The main goal of this study was to assess the feasibility of applying a P-ARET intervention for adults with cockroach phobia. We tested varying phobic stimuli and evaluated the participants' user experience for treatment modalities. Furthermore, we evaluated the preliminary efficacy of the P-ARET and analyzed other outcomes related to the feasibility, such as adherence to a daily monitoring app. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**VD** & **POST-Treatment** & **1-Month Follow-Up** & **6-Month Follow-Up** \\ \hline BAT (Fear) & & & \\ Recovered & 0 (0\%) & 4 (100\%) & 4 (100\%) \\ Improved & 4 (100\%) & 0 (0\%) & 0 (0\%) \\ No significant change & 0 (0\%) & 0 (0\%) & 0 (0\%) \\ Deteriorated & 0 (0\%) & 0 (0\%) & 0 (0\%) \\ \hline BAT (Avoidance) & & & \\ Recovered & 3 (75\%) & 3 (75\%) & 4 (100\%) \\ Improved & 0 (0\%) & 1 (25\%) & 0 (0\%) \\ No significant change & 1 (25\%) & 0 (0\%) & 0 (0\%) \\ Deteriorated & 0 (0\%) & 0 (0\%) & 0 (0\%) \\ \hline BAT (Negative & & & \\ beliefs) & & & \\ Recovered & 3 (75\%) & 4 (100\%) & 4 (100\%) \\ Improved & 1 (25\%) & 0 (0\%) & 0 (0\%) \\ No significant change & 0 (0\%) & 0 (0\%) & 0 (0\%) \\ Deteriorated & 0 (0\%) & 0 (0\%) & 0 (0\%) \\ \hline BAT (Performance) & & & \\ Recovered & 2 (50\%) & 2 (50\%) & 4 (100\%) \\ Improved & 1 (25\%) & 1 (25\%) & 1 (25\%) \\ No significant change & 1 (25\%) & 1 (25\%) & 0 (0\%) \\ Deteriorated & 0 (0\%) & 0 (0\%) & 1 (25\%) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Change in the BAT outcomes based on previous studies on the effectiveness of AR on cockroach phobia. Figure 3: Participant 2: Evolution in the level of avoidance. NAP: non-overlap of all pairs. D1–D34 refers to the days in which the treatment phase is evaluated with the app. First, the participants did not show a clear preference for either of the two treatment modalities (SS or MS). However, the four participants considered the MS version more effective and would recommend this option to a friend. Importantly, however, the participants also considered it more aversive than SS, probably due to the similarity to real-world situations and the number of different feared stimuli they had to face simultaneously. Our study results are in line with previous works related to optimizing exposure therapy by using a variety of stimuli [7; 9]. Patients find stimulation variability more useful and effective, and they report that this methodology makes the therapeutic process easier. Adherence to the Emotional Monitor app was generally high, except for one participant who only registered about half of the days. The findings align with earlier research on the mobile application [21; 22] and provide backing for the notion that conducting ecological momentary assessment through an app is viable. In the case of the participant with lower adherence rates, she mentioned that, on the baseline days, she was taking career exams and, therefore, found it difficult to complete the assessments. Finally, regarding the preliminary efficacy of the P-ARET treatment, we found that it was effective for all the patients across all the outcomes, even in the long term. We found significant decreases in psychological and behavioral symptoms associated with the phobia throughout the treatment, at post-assessment, and at follow-ups. These reductions were evident in the data obtained from the mobile app and the BAT test, which are consistent with the idea that mixed realities are effective alternatives to iVET for SP [23]. Despite the positive results, individual variability in response to the treatment is noticeable. For example, P1 exhibited the most consistent and significant improvements across measures of fear, avoidance, and dangerousness, while P2 showed milder effects in fear and avoidance. About P2, it is important to note that this patient obtained the poorest adherence levels to the mobile app and indicated being in the middle of the exam period at university, which may have influenced the anxiety levels reported and engagement with therapy.