One popular misconception being propogated through society at the moment is the statement that various conditions that are labelled as disorders are chemical in nature. Things like OCD, ADHD, and numerous others.
They are based on observations only and there are no scientific tests to confirm the presence or absence of chemicals in the brain as being the cause.
The intention however is to be able to say "we have a drug that will help you" and therefore increase profits of the pharmacuitical companies.
Diseases can be shown clinically to be present by various tests. There are no tests to show such things as neurotic twitching so it is therefore not a disease.
The presence of chemicals in the brain when someone experiences an emotional state is looked at in reverse. The emotional state is creating the chemicals not the other way round.
To say otherwise would be to say that when someone has a red face and high blood pressure they are going to feel angry. No, the feeling of anger is what causes the red face and the high blood pressure.
So to then try and handle someones blood pressure with drugs rather than dealing with the anger is to say the least putting the cart before the horse ie backwards.
To look at the real cause of the disorder one must look to the mind. Specifically the reactive part of the mind. When this is understood one can then see there is something that can be done about about unwanted feelings, emotions, habits , twitches and a whole host of other forms of behaviour that isn't generally understood.
The book "Dianetics the modern science of mental health" explains the whole thing in full and gives workable techniques to eradicating these unwanted conditions.
One thing I can suggest as an exercise which may sound a bit odd is rather than trying to stop the twitching or whatever, try to do it causitively.
See if you can twitch faster or slower or if it happens only on the right side try to make it twitch on the left side. By taking over control of the twitch very often the person finds that the mental circuit that is creating it can lose its control and often disappear.