In this final part of the free will series, we take a look at the relationship between the concept of free will and mental health. Is free will altered in those suffering from schizophrenia? How is well-being related to free will? Thinking about these questions and the rise of neuroessentialism within psychiatry allows us to recognize the influence of our environment on our decision-making. The debate is far from settled, but a belief in free will clearly affects daily life and the practice of psychiatry.