However, true psychogenic pain is considered to be rare. Some sources have assigned or categorized AFP as a psychosomatic manifestation of somatoform disorder, as defined in the Diagnostic and Statistical Manual of the American Psychiatric Association. Distinction should be made between somatoform disorder, where affected individuals are not inventing the symptom for some benefit, and other conditions like factitious disorder or malingering.Recent evidence in chronic facial pain research appear to suggest that a proportion of individuals who have been diagnosed with AFP have neuropathic pain,AFP is described as one of the 4 recognizable symptom complexes of chronic facial pain, along with burning mouth syndrome, temporomandibular joint dysfunction (TMD) and atypical odontalgia. However, there is a degree of overlap between the features of these diagnoses, e.g. between AFP and TMD and burning mouth syndrome. Atypical odontalgia is similar in nature to AFP, but the latter term generally is used where the pain is confined to the teeth or gums, and AFP when the pain involves other parts of the face. Other sources use atypical odontalgia and AFP as synonyms, or describe atypical odontalgia as a sub-type, variant, or intra-oral equivalent of AFP. Sometimes "phantom tooth pain" is listed as a synonym for AO, and sometimes it is defined as toothache which persists after a tooth has been extracted. It has been suggested that it is likely that these terms do not represent a single, discrete condition, but rather a collection of misdiagnosed and as yet unidentified causes.
Depression and anxiety are often associated with AFP, which are either described as a contributing cause of the pain, or the emotional consequences of suffering with unrelieved, chronic pain. For unknown reasons, AFP is significantly more common in middle aged or elderly people, and in females. Atypical odontalgia (AO) is very similar in many respects to AFP, with some sources treating them as the same entity, and others describing the former as a sub-type of AFP. Generally, the term AO may be used where the pain is confined to the teeth or gums, and AFP when the pain involves other parts of the face. As with AFP, there is a similar lack of standardization of terms and no consensus regarding a globally accepted definition surrounding AO. Generally definitions of AO state that it is pain with no demonstrable cause which is perceived to be coming from a tooth or multiple teeth, and is not relieved by standard treatments to alleviate dental pain. Depending upon the exact presentation of atypical facial pain and atypical odontalgia, it could be considered as craniofacial pain or orofacial pain. It has been suggested that, in truth, AFP and AO are umbrella terms for a heterogenous group of misdiagnosed or not yet fully understood conditions, and they are unlikely to each represent a single, discrete condition. Signs and symptoms
Some sources list some non-specific signs that may be associated with AFP/AO.