What is the difference between someone having learning difficulties and having mental health problems?

These often overlap: Mental health (mh) diagnoses include learning difficulties (e.g. Adhd), but many other mh disorders can cause learning problems, e.g. Concentration/memory impairment is a symptom of depression. Though in my mind, subnormal IQ is not a mh disorder per se (though the dsm includes "borderline intellectual functioning"), it does explain most of what we label as "learning difficulties" in children.