Withdrawal symptoms frequently follow abrupt discontinuation of
antipsychotic compounds. In addition to other somatic symptoms,
withdrawal-emergent dyskinesias may be observed. "Covert dyskinesia" refers
to a masked form of tardive dyskinesia that becomes clinically detectable
only after antipsychotic drugs are withdrawn or their dosage is reduced.
Withdrawal dyskinesia appears under similar circumstances but disappears
spontaneously in 6 to 12 weeks. Cholinergic overactivity and changes in
dopamine-acetylcholine balance in the basal ganglia may underlie these
withdrawal syndromes. The principal value of the concept of covert
dyskinesia is in the secondary and tertiary prevention of tardive
dyskinesia through early discovery and treatment.