Table 2 Main clinical trials performed involving adults on the effects of probiotics on neurologic diseases

Messaoudi et al. [97]

Double-blind, placebo-controlled, randomized trial on healthy volunteers treated with the oral administration of L. helveticus R0052 and B. longum R0175 vs. placebo for 30 days

Reduced psychological distress and urinary free-cortisol level in probiotics arm

Tillisch et al. [98]

Randomized controlled clinical trial on healthy women treated with fermented milk containing B. animalis subsp. lactis, S. thermophiles, L. bulgaricus and L. lactis subsp. lactis vs placebo for 4 weeks

Reduction in responsiveness to negative emotional stimulations in probiotics arm

Matsuzaki et al. [99]

Prospective, uncontrolled treatment with L. casei strain Shirota for 4 weeks in patients suffering HTLV-1 associated myelopathy/tropical spastic paraparesis

Improvement in motor dysfunction, urinary symptoms and spasticity in lower extremities

Rao et al. [100]

Double-blind, placebo-controlled, randomized trial in patients with chronic fatigue syndrome treated with L. casei strain Shirota vs placebo for 2 months

Decrease in anxiety symptoms in probiotic arm