The main objective of this study is to make a first evaluation of the relationship between metabolic abnormalities objectified by Positron emission tomography with 2-deoxy-2-[fluorine-18]fluoro- D-glucose integrated with computed tomography (PET CT 18 FDH) performed at rest at the onset of symptoms in patients with a first episode of motor conversion disorder and the persistence of a motor disability at 6 months measured by the modified Rankin score (mRS).

The secondary objectives of this study are:

A. To assess whether metabolic abnormalities objectified by PET CT 18 FDH performed at rest at the onset of symptoms may be predictive of persistent disability at 6 months as measured by the EDSS, the NIHSS and WHO status.

B. To assess whether metabolic abnormalities objectified by PET CT 18 FDH performed at rest at 3 months after diagnosis may be predictive of persistent motor disability at 6 months (EDSS, NIHSS, mRS, WHO) C. To search for and characterize any abnormalities of metabolism objectified in the initial PET CT 18 FDH predictive of persistent motor disability at 3 months.

D. To determine if there are persistent metabolic abnormalities 3 months post-diagnosis independently of the clinical course (marker trait).

E. Define the brain areas whose metabolism is often altered in patients with motor conversion disorders.

F. Establish a collection of biological samples from patients for future research studies of prognostic biomarkers of a motor conversion disorder.

Inclusion Criteria:

• The patient must have given free and informed consent and signed the consent
• The patient must be affiliated with or beneficiary of a health insurance plan
• The patient meets DSM-IV criteria for motor conversion disorder (with paralysis, motor weakness or abnormal movements) lasting for less than 1 month and euthymic (HAMD score < or = 7, as evaluated by a psychiatrist)
• First episode (incident cases)
• The latest symptom dates to within a month
• The patient is not under neuroleptics

Exclusion Criteria:

• The subject is participating in another study
• The subject is in an exclusion period determined by a previous study
• The subject is under judicial protection, guardianship or curatorship
• The subject refuses to sign the consent
• It is not possible to correctly inform the patient
• The patient is pregnant, parturient or she is breastfeeding
• Specialized clinical neurological examination and brain and spinal cord MRI revealed an organic neurological cause
• The subject has a HAMD score > 7
• The subject currently has manic/hypomanic episode, a diagnosis of substance abuse or dependency (excluding tobacco), a diagnosis of schizophrenia (any time in the past) or chronic neurological disease (active epilepsy, stroke, brain tumor)
• Suicidal or high risk for suicide (according to MINI assessment)
• Contra-indication for a PET scan
• Patient under neuroleptics at inclusion
• The last symptom happened over 1 month ago
• The patient has had previous episodes (prevalent cases)

The study population consists of patients with paralysis, motor weakness or abnormal movements meeting DSM-IV criteria for motor conversion disorder consulting via the Emergency or Neurology department of participating centers.