The development of generative AI and deepfake has definitely created a lot of opportunities in the field of mental health therapy, with new tools for diagnosis, treatment, and patient engagement coming on board. This comparative study looks at the use of generative AI and deepfake technology and their incorporation into mental health therapy, taking into consideration the advantages and disadvantages. Furthermore, the deepfake technology facilitates the replacement of these even further through the provision of realistic voice and moving pictures, which can be used for virtual therapy, and role-playing. The investigation looks at how these technologies have improved the therapeutic engagement, the accessibility, and the personalization aspects of the treatment. Some of the major ones are being able to offer 24/7 support, enabling the creation of surrounding for therapy, and the ability to customize treatment. Given the ability of the virtual therapy sessions to eliminate location and economic barriers, it is easier to provide mental health care. Though there exist great benefits of these technologies, issues including the technological ability to generate linking with the context still exist. In addition, the use of such technologies in existing mental health care systems poses a challenge that must be addressed to ensure the compatibility of the new practices with the existing ones. This research signifies the importance of ongoing research and development into the quality and fidelity of generative AI and deepfake technologies utilized in mental health therapeutics, therefore facilitating the personalization of support and outcomes for the patients.