OnabotulinumtoxinA in the Management of Psychogenic Dystonia

The purpose of this research study is to evaluate if patients with psychogenic dystonia treated with onabotulinumtoxinA (BOTOX) injections will demonstrate lower severity and disability at one month and at three months than those having received placebo injections

Specific Aim 1: To investigate the effect of BoNT on PsyD severity and disability. We will measure the changes in severity, duration, and incapacitation scores of the Rating Scale for Psychogenic Movement Disorders (RSPMD)10 in adult patients with clinically definite PsyD one month after intramuscular injections with onabotulinumtoxinA in selected muscles of the affected limb(s). H1: PsyD patients treated with onabotulinumtoxinA injections will demonstrate lower severity and disability at one month than those having received placebo injections. Specific Aim 2: To investigate the effect of CBT on PsyD severity and disability with and without BoNT pretreatment. We will examine the extent to which any changes in severity and disability of PsyD, as measured by the RSPMD, after 12 weekly CBT sessions, can be influenced by pre-CBT injections with onabotulinumtoxinA.

Participants will be randomized to receive BoNT (onabotulinumtoxinA). Patients will undergo study assessments four weeks later. We will inject a total of 250 units of onabotulinumtoxinA, as the average optimal dose in cervical dystonia,11 using a 100:1 dilution with normal saline. The target muscles will be the ones deemed most active in the cervical region or in any of the affected limbs. If several limbs are affected, only up to two will be targeted in similar fashion, with a total dose not to exceed 400 units altogether (250 +150 units, if involvement is asymmetric or unilateral [leg and arm, respectively]; 200 + 200 units, if involvement is symmetric).

Participants will be randomized to receive normal saline (placebo). We will inject a total of 250 units of normal saline, as this is the average optimal dose of onabotulinumtoxinA in cervical dystonia. The target muscles will be the ones deemed most active in the cervical region or in any of the affected limbs. If several limbs are affected, only up to two will be targeted in similar fashion, with a total dose not to exceed 400 units altogether (250 +150 units, if involvement is asymmetric or unilateral [leg and arm, respectively]; 200 + 200 units, if involvement is symmetric).

All participating subjects will start a 12-week CBT treatment program. These consist of weekly 1-hour CBT sessions led by a cognitive therapist. Assessments will be repeated at week 16. All PsyD subjects will undergo a 15-minute, structured diagnostic interview (Mini International Neuropsychiatric Interview (MINI)) developed to screen for axis I DSM-IV and ICD-10 psychiatric disorders. We will also use two clinician-rated instruments to assess comorbid psychopathology in PsyD patients, the 17-item Hamilton Depression Rating Scale (HAM-D), to evaluate for depressed mood, vegetative and cognitive symptoms of depression; and the 14-item Hamilton Anxiety Rating Scale (HAM-A) to evaluate psychic and somatic anxiety. These scales will be administered as part of a structured interview.

Primary outcome measures will be the combined severity, duration factor, and incapacitation scores (investigator-rated) of the Rating Scale for Psychogenic Movement Disorders (RSPMD, 0-12 per each limb and head [maximum for all five regions: 60]) (see Appendix 1).

Inclusion Criteria: Subjects must meet standard criteria for clinically definite PsyD;17 PsyD severity and disability score ≥ 10 as measured by the RSPMD (Appendix 1);10 Dystonic posturing must have been present without remission for a period longer than 1 year. Between the ages of 18 and 75, inclusive Exclusion Criteria: Prior treatment with any BoNT Presence of clinically unstable medical condition other than the condition under evaluation Concurrent participation in another investigational drug or device study within 30 days prior to study enrollment. We will also exclude subjects with medical disorders deemed at increased risk when exposed to BoNT, including myasthenia gravis, Eaton-Lambert syndrome, amyotrophic lateral sclerosis, or other neuromuscular disorders.