Although using mobile phone apps to track and monitor mental health is increasingly popular, we know little about how and why people with mental health diagnoses use such technologies, nor do we know of concerns they may express about these apps. Further, automated assessments of mental health status, or digital phenotyping, are also on the rise; how people with mental health conditions feel about such technologies is also an underexplored area of research. This paper presents an exploratory interview study with 12 people that begins to address these gaps. We focus specifically on how participants, who all have been diagnosed mental health conditions, perceive tech companies' involvement with existing mental health apps and mental health digital phenotyping. We find that participants satisfice in order to interact with existing mood tracking apps, and that they are wary of digital phenotyping for mental health diagnostics. Participants raise concerns related to profit motives, distrust, and fatalism in both cases, and they recommend regulations that may be put in place to keep tech companies in check. Though participants describe regulatory policies that may mitigate their concerns, we question whether regulations can truly foster sustainable interactions with mental health apps operated by technology companies.