Metal disorder is the disruption of the mental processes. Mental processes are the processes involved in the working together of mental units to produce an effect such as that related to a mechanism but in this case, the brain an its neurons.
Many people may confuse mental disorder with behavioural disorder but here, I would suppose there is hardly a line of demarcation between both of them.I would suppose most behavioural disorders result from mental disorders, and whatever is mental has to relate to the mind. The mind is a non-physical entity which the mental (physical entity) has come to explain.
I would also elucidate that the theories of Freud is quite hypothetical construct of non-physical entities that is, the mind and parts of personality namely Id, ego, and super ego would seem meaningless if no other entity as the mental or physical exist to explain it further.
Consider the human brain which is in fact in the real sense that physical entity I am talking about here. If no brain exist, the mental wouldn’t exist and as such, no mind.
So I would further suppose that all mental disorders could result in behavioural disorders since the brain controls or regulate nearly all functions of the human body.
Can you name a part of the body that the brain doesn’t control? Since the brain controls a good number of behaviours, alteration in the brain or would also mean an alteration in behaviour and as such, behavioural disorder is what results.
Consider further the Case of schizophrenia which is a mental disorder because of the malfunctioning of the brain and alteration in the perceptual processes to the extent of exaggerating these processes often resulting in the hallucination paired with delusion. If these are all mental dis-organizations, is the associated behaviour not disorganized or disordered as well?
Consider further that the schizophrenic smile or laugh at a car accident that result in the loss of many lives. Is this kind of behaviour not disordered?
You may also consider further that at the instance of seeing Faeces, the schiziphrenic misrepresent it with a well prepared Salad or Pizza. Is this behaviour organized?