## 4 Results and Discussion
It can be seen in Figure 5 that racing games have been utilized the most, followed by therapeutic VR, exergames and shooter games for intervention for individuals with depression. For interventions for individuals with anxiety, adventure games and social VR were utilized the most, followed by therapeutic VR. Therapeutic VR and social VR were the most utilized for intervention for individuals with phobias, followed by racing and exploration games. For individuals with bipolar disorder, therapeutic VR and social simulation games were mostly utilized as interventions, and for emotional dysregulation of anger and aggression an action game was utilized. Figure 3: Dimensionality of the games used for each affective disorder. Figures 3-5 clearly show some trends for the game design characteristics that had been applied in games which were effectively utilized as therapies for the different affective disorders, which were:  
* For depression and its comorbidities: 11 games were applied and the most frequently occurring player perspective, game dimensionality and genre were 3D at 63.64% (7/11), first person/immersive at 36.36% (4/11) each and racer at 27.27% (3/11), respectively. * For anxiety and its comorbidities: 14 games were applied and the most frequently occurring player perspective, game dimensionality and genre were 3D (VR) at 57.14% (8/14), immersive at 50% (7/14) and adventure at 28.57% (4/14), respectively. * For phobias and its comorbidities: six games were applied and the most frequently occurring player perspective, game dimensionality and genre were 3D (VR) at 83.33% (5/6), immersive at 100% (6/6) and therapeutic VR/social VR at 33.33% (2/6) each, respectively. * For bipolar disorders and its comorbidities: two games were applied and the most frequently occurring player perspective, game dimensionality and genre were 3D/3D (VR) at 50% (1/2) each, isometric 100% (2/2) and therapeutic VR/social VR at 50% (1/2) each, respectively. Figure 4: Player perspectives of the games used for each affective disorder. Figure 5: Genre of the games used for each affective disorder. * For emotional dysregulation of anger and aggression: one game was applied and its perspective, game dimensionality and genre were 2D, isometric and action, respectively. Hence, it could be stated that for depression and its comorbidities, serious games that were 3D, first-person/immersive, and racing games were more effective as therapies in the reviewed studies. Similarly, 3D (VR), immersive, adventure or social VR games have been more effective interventions for anxiety and its comorbidities while 3D (VR), immersive, and therapeutic VR/social VR games have been more effective as interventions for phobias. In the case of serious game applications for bipolar disorder as well as emotional dysregulation of anger and aggression, there were far too few studies that fit the eligibility criteria for this review and so any kind of trends observed for these two affective disorders cannot be free from bias. This is understandable as 3D and 3D (VR) games promote greater levels of better engagement through an increased presence in the virtual world than 2D games [44,103]. Likewise, between first-person and third-person player perspectives, players tend to show greater engagement when they see the game world through the eyes of the playing character [104]; hence, for a 3D game, it makes sense for successful interventions to utilize this fact by utilizing the first person player perspective. As for the genres of games seen in the reviewed studies, racing, adventure and therapeutic/social VR games all provide a distraction from negative thoughts and emotions, relaxation and a sense of accomplishment [44,46,49,52,68,98,105]. Additionally, adventure games have an added benefit of the element of exploration [59], which makes the experience rewarding and hence engaging. An important point to note is that for depression, whether for ASD or the neurotypical population, all instances of serious game interventions showed a positive impact on the participants.