Functional disorders cover a wide range of problems and many are not diseases as such but rather symptoms of certain underlying disorders. 

Functional disorders stretch from the common Headache over the more violent Horstons headache and Migraine to diseases such as Epilepsy, Aphasia, Myasthenia Gravis to the more complex diseases such Neuralgia, Involuntary muscle movements, also called Dystonia, and further to dimmer disorders such as Tics in the form of Tourette's syndrome, Sleep Apnoea and Restless Legs Syndrome.

Read about these diseases and about causes, treatment and prevention of this large group of brain and central nervous system disorders.