Should psychological checks be as frequent as physical checks to evaluate a patient's condition?
ABSOLUTELY! The physical and mental are often connected. Take, for instance, the Thyriod. If the thyroid is physically unhealthy then it can cause mental disturbances. It can cause a slew of psychological manifestations for someone. When preceived by a psychological professional, they treat the symtoms they interpret and preceive from their paradigm they treat their patient with psychological techniques and medications. 

I have seen this first hand where someone can exhibit pyschological disturbances and are incorrectly diagnosed because the psychological professional does not test their physical state.