With the advent of medical screening technologies, such as electroencephalography (EEG) monitoring,<unk> s are becoming much more common as medical professionals have increasingly precise tools to monitor patients. When a patient does not display typical markers of a disorder that could show up from medical exams, physicians typically diagnose a patients symptoms as being<unk> . Research into understanding<unk>  disorders has led to the development of both electronic diagnostic tests for ruling out the usual biological markers of a disorder and new clinical observation procedures. An example of something a physician would look for when testing for<unk>  symptoms is if the symptom changes with suggestion (e.g. a patient is told to use a tuning fork to aid symptoms in a movement disorder). Despite the understanding of<unk>  symptoms, there are some problems with the assumption that all medically unexplained illness must have a psychological cause. It always remains possible that genetic, biochemical, electrophysiological, or other abnormalities may be present which we do not have the technology or background to identify. Some patients may also have their symptoms diagnosed as<unk>  even with a lack of evidence to suggest there are psychological causes. Misdiagnoses of<unk>  may be simply accidental, but they can also come from bias. For example, a doctor with a bias towards women may tell men that their symptoms are<unk> , despite them being actual symptoms for a physical disease. This would then be contrasted with a woman experiencing the same symptoms being treated differently, with the physical disease being detected.
Psychogenic disease
Neurodegenerative disease
Vitamin deficiency
Viral disease
Metabolic disorder
Diathesis 
Degenerative disease
Parasitic disease