The condition is known as tardive dyskinesia and is a common side-effect of the use of antipsychotic medications such as the one your son is currently taking. This is not a well-understood side effect and affects patients in s variety of ways as well as levels of intensity. These are involuntary spasms which include symptoms like your son's. This should be brought to the attention of his therapist as soon as possible. An alternative antipsychotic may help and medications have been and are being developed to counteract these disturbing physical symptoms. Other symptoms can include licking the lips, the tongue darting in and out, unusual blinking and even verbal shouts or noises of short duration. This can easily affect your son's self-confidence as people around him can find these symptoms frightening and authority figures such as police officers may misinterpret these involuntary symptoms as rudeness, or 'street drug' induced. So it is best to seek medical advice as soon as possible. At present, there is no 'cure' for this, and it may be permanent even if the anti-psychotic treatment is interrupted or a substitute drug is employed. People on long-term SSRI and SSNI medications for depression are also occasionally being discovered with the development of this disturbing physical issue. The good news is that with the sweeping advancements in genetics, new and more efficacious treatments are coming forward every day. It is the social consequences which can make this condition potentially dangerous through the overreaction of a member of the public or police. Until some resolution is found working with your doctor, it might be wise for your son to carry a doctor's note in his wallet or some kind of medical bracelet, that would indicate that he has a 'neurological' condition that causes involuntary body movement or facial expressions that are entirely benign, carry no danger to others and are not under his control. CAUTION: This condition does not develop in everyone using antipsychotic medications or some types of anti-depressants. NEVER abruptly discontinue the use of your medication or that of the person for whom you are caring. This could be very dangerous. Seek medical advice before stopping any prescribed medication.