Vaporized Cannabis and Spinal Cord Injury Pain

This study will demonstrate that vaporized cannabis can produce antinociceptive effects
compared to placebo in human subjects with spinal cord injury (SCI). A within-subject
crossover study of the effects of cannabis versus placebo on spontaneous and evoked pain
will be performed. A synopsis of antinociception with mood, cognitive impairment,
psychomotor performance, and side effects will be obtained to help evaluate the utility of
vaporized marijuana in SCI neuropathic pain.

This study will compare the analgesic and side effect profile of low (3.5%) to high dose
(7.0%) delta 9-tetrahydrocannabinol in subjects with spinal cord injury pain. It is
hypothesized that a low dose will produce a lesser degree of neuropsychological impairment
while maintaining a similar degree of pain relief to the higher dose. The use of two
different strengths will help determine tolerable dosing for the treatment of SCI
neuropathic pain.

Inclusion Criteria:

1. Age greater than 18 and less than 70

2. Pain intensity ≥ 4/10

3. Neuropathic pain defined as chronic pain in an area of sensory abnormality
corresponding to the spinal cord or nerve root lesion, and the pain should have no
primary relation to movement, inflammation or other local tissue damage

4. Leeds Assessment of Neuropathic Symptoms and Signs score greater than or equal to 12

5. Spinal cord injury of 3 or more months duration (to avoid spontaneous recovery
obfuscating generalizability)

Exclusion Criteria:

1. Known concomitant cerebral damage/cognitive impairment (TBI, Alzheimer's Disease
Vascular dementia, Parkinson's disease, dementia with Lewy Bodies and Front temporal
dementia

2. Clinically significant or unstable medical condition (i.e., cardiac, respiratory,
hepatic or renal disease) that, in the opinion of the investigator, would compromise
participation in the study

3. Neurologic disorders unrelated to spinal cord injury that may confound the assessment
of the central neuropathic pain due to spinal cord injury (hereditary neuropathies;
diabetic peripheral neuropathy; traumatic neuropathy; and immune-mediated
neuropathies)

4. Active substance abuse within past year using "The Substance Abuse Module of
Diagnostic Interview Schedule for DSM-IV

5. Pregnancy as ascertained by a self-report and a mandatory commercial pregnancy test

6. Currently on probation or parole.

7. Hx of Schizophrenia, Bipolar Depression with Mania, current suicidal ideation or past
history of suicide attempt 8. Severe depression (Patient Health Questionnaire-9 ≥ 15)
9. Current suicidal ideation