Whilst I am not sure what attracts mental health workers in general, I am very skeptical of the motives of people who become psychiatrists and psychiatric nurses, a conviction that has an experiential component given the experience I have had on wards and with psychiatrists. The most worrying thing is that psychiatry offers a kind of legal haven to what are commonly known as "psychopaths" (a label I reject), a place they can act on their impulses free from judicial scrutiny and the moral strictures of the populace. If people's critical, reasoning and judicative faculties weren't so impaired in this regards, I think there would be greater acknowledgement of this.
Instead, people prefer to plumb to even greater depths of naivety than they would regarding other classes fertile for the growth of corruption, claiming that psychiatrists simply want to help their patients, ignoring firstly the many distancing mechanisms and barriers that seperate and estrange people emotionally and spiritually in modern societies, mechanisms which militate against the forging of empathic bonds and which serve to lay the groundwork for abuses and complicity in abuse, both being two of the threads out of which the vast historical and contemporary tapestry of the profession has been woven, at least from my perspective. It is not that psychiatrists are in general evil or sadistic (although who knows!), but human, all too human, with all the limitations that generally human flesh and specifically man in modern society is heir to.