Hello Msmoreinfo and welcome to NeuroTalk.

There is a diagnostic criteria for diagnosing MS ~ The Revised McDonald Criteria. Optic Neuritis can be a first symptom of MS but it can also be a stand alone diagnosis.

MS is a disease of the Central Nervous System(CNS) which includes the brain and spinal cord. There is no symptom(s) that is exclusive to this disease. Many other conditions can cause symptoms similar to MS.

Your Neurologist will order more testing and perform a Neurological exam/evaluation. The road to a diagnosis of MS or something else can take time and patience.

As far as Cocaine; I am not aware of it causing or increasing your risk of having MS. MS is a demyelinating disease, our own body is attacking myelin which is the protective coating surrounding our nerves. Our body considers Myelin a foreign object and destroys it as it would attack an infection or virus my may get.