As is generally the case with other medical specialties, consultant psychiatrists will make significantly more money than other health professionals working in the mental health field, e.g. psychiatry trainees, psychologists, social workers and nurses.

It's hard to say which actual field of psychiatry makes the most money. 

There are certain subspecialties in psychiatry that are more limited to working in public hospital settings, for e.g. consultation-liaison psychiatry, so these consultants will earn a bit less than someone working in the private sector. 

Subspecialties that lend themselves best to private sector work, and which will, therefore, have higher earning potentials, including forensic psychiatry and adult psychiatry.