This course examines several clinical conditions that may meaningfully affect an accused’s fitness to stand trial and discussions of to what extent these conditions are recognized by courts as limiting factors. We begin with a discussion of psychosis, as the most common mental disorder leading to a finding of unfitness. We also discuss amnesia, deafness and inability to speak, intellectual limitations, paranoia, and mania and how these affect an accused’s fitness. We conclude that understanding the trial process and its consequences are central to fitness, but other factors such as perspective, motivation, and rationality must also play a role in determining fitness.