Formication is the sensation that “bugs” are crawling on or under the skin. Essentially a tactile hallucination, it is unclear whether this is more a dermatological (skin) condition or a psychological issue (although research suggests it is psychological in origin). It is normal for people to briefly experience this sensation when seeing (on TV) or even thinking about bugs (especially ants) but to have this sensation frequently, or to actually believe that they are infested by insects, can be a serious problem that should be first evaluated by a physician and then perhaps by a psychologist or therapist. Some conditions with formication as a symptom are Parkinson’s disease, schizophrenia, anxiety disorders, shingles, Lyme disease, and drug withdrawal.