The efficacy of Turmeric as an antidepressant is comparable to that of antidepressants. 
A study done shows Turmeric’s efficacy relative to the common antidepressant Prozac. In the study, 60 patients diagnosed with Major Depressive Disorder were randomized and given either turmeric, Prozac, or both. There was a 64.7% positive response with Prozac, a 62.5% positive response with just turmeric, and a 77.8% positive response when both were given.
The difference is, Prozac has negative side effects, where Turmeric has other positive health benefits. So what’s the word?
“This study provides first clinical evidence that curcumin may be used as an effective and safe modality for treatment in patients with MDD without concurrent suicidal ideation or other psychotic disorders.”
Conclusion: The active ingredient Curcumin works neurochemically by increasing levels of the neurotransmitters Serotonin, Dopamine, and Norepinephrine, which are all responsible for feelings of happiness, motivation, and joy. Curcumin also works to modulating the hormone cortisol, which is stress hormone. 
Adding just one gram of turmeric to breakfast could help improve memory. Emeritus Professor Mark Wahlqvist, from the Monash Asia Institute at Monash University recently led a study in Taiwan that tested working memory of men and women aged 60 or over who were prediabetic. He said that, “Working memory is widely thought to be one of the most important mental faculties, critical for cognitive abilities such as planning, problem solving and reasoning, he said.
Conclusion: The findings of his study were consistent with observation; turmeric appears to influence cognitive function where there is disordered energy metabolism and insulin resistance. 
Curcumin is normally the one that gets all the awards for being the most efficacious component in turmeric. Although this is true, there is one study that focuses on Aromatic-tumerone, which is another bioactive component of Turmeric. Aromatic-Tumerone, according to the study has the remarkable ability to facilitate neurogenesis by speeding up the rate at which neural stem cells differentiate into functioning neurons. The process was increased by an shocking 50 – 80%.
The same studied also displayed ar-turmerone’s ability to move to areas of the brain that require new neurons. 
Conclusion: Turmeric can aid in the regeneration of new brain cells where needed in the brain!