Seeming Cause of OCD
I feel that the cause of OCD is depression, and , a state of constant defeat in life, and no further way, or some sort of dissatisfaction i.e. some desire is unfulfilled, some intentions are not happening, or some thoughts are not fulfilled.
A sort of lacking of love and care consistently results in OCD.
Also the person becomes careless for self, and this effects his health negatively, causing the suppy of nutrients and oxygen to brain is minimised. The brain being a body part gets deficient and results into disorders.
Livning in an area with high radiations also is one factor which may cause disturbance of brain signals and communications systems. We know that the brain also has its own neuron signals which are of electromagnetic nature.
Generally after a long illness this orignates which signifies that due to illness the brain was slightly damaged. A rehabilation plan after treatment of a long sickness is a must. e.g. tuberclosis... the medicines damage liver, and consequently the metabolism of the individual is effects which in turn effects many other parts of body ,,, brain being one.
I am not an expert but these are the possible causes and if these are checked and reversed..improvement may be noticed by Gods grace.