Is there a correlation between seasonal affective disorders (sad) and occupational injuries?

No and Yes: Used to be this case in medical field now we work as a team and cross check each other, have quality management people who review internally we have external audits, computers with smart alerts so it is a lot better. So technically answer is no. But as a spirit if we are functioning without awareness without intension can cause harm. Medicine is team work thank god for that.

Any depression: Or anxiety could increase risk of occupational injury by effecting concentration, alertness, fatigue, decision making, etc. Much would depend on the severity of the sad and the skills required by the occupation.

Not directly: Since sad has an impact on a person's level of functioning it is reasonable to assume that other aspects of life would be affected. But there isn't any direct relationship to injuries.