Being neuroprotective, creatine may also target a range of mood disorders and brain diseases. 
Creatine supplements (4 g/day) added to SSRI antidepressants improved symptoms in 5 women suffering from depression who previously didn’t respond to therapy. Brain imaging revealed that creatine increased phosphocreatine levels, which explains its mood-enhancing effects. It may be a safe add-on for people who don’t respond to antidepressants .
Creatine (8 g/day) reduced a marker of DNA damage in a trial on 64 people with Huntington’s disease (8-hydroxy-2-deoxyguanosine). It was safe, well-tolerated, and increased creatine levels in both the blood and brain .
In brain cells, creatine protected GABA neurons from damage. The destruction of GABA neurons and impaired energy balance in the brain are characteristic of Huntington’s disease .
However, creatine didn’t offer any benefits to people amyotrophic lateral sclerosis in one trial. This progressive disease that destroys nerve cells and impairs the mitochondria, while creatine (5 g/day) is powerless at targeting this process [39, 40].
Parkinson disease often leads to poor fitness, decreased muscle mass, reduced muscle strength, and fatigue. Creatine improved upper body strength and enhanced the benefits of resistance training in one study of 20 people with Parkinson’s Disease. Similar to its use in athletes, creatine was loaded in higher doses for 5 days (20 g/day) and then maintained at a lower dose (5 g/day) .
Although promising, larger clinical trials would need to assess if creatine supplements alone may also improve other symptoms in Parkinson’s Disease.
In mice, creatine prevented a drop in dopamine levels. Low dopamine and the destruction of dopamine neurons is the hallmark of Parkinson’s Disease that triggers common symptoms .