Lithium (treatment for bipolar disorder)

Lithium, normally in the form of lithium carbonate (Li₂CO₃) is widely recognised as the 'gold standard' prescribed drug for treating bipolar disorder, depression and mania.

In widespread use since the early 1970s, lithium carbonate was the first FDA approved drug for 'mood control'.

However, despite more than forty years of intense research, and millions of treated patients - "The precise mechanism of action of Li⁺ as a mood-stabilizing agent is currently unknown." Source : Wikipedia

In 1996 it was found that lithium inhibits GSK-3, a multi-tasking serine/threonine kinase enzyme which regulates several critical cellular functions. It's not known however, how this inhibition affects mood. (ref.)

Further, for reasons that are also unknown, therapeutic lithium has little or no effect on some individuals :

Lithium is generally regarded as the first-line agent for the management of BP, although it does not work for everyone. For instance, Geddes and colleagues performed a meta-analysis of five randomized controlled trials comparing prophylactic lithium therapy with placebo in BP and found that lithium is more effective than placebo in preventing recurrence of illness, with 60% in the lithium group remaining well over 1–2 years compared with 40% in the placebo group."

Source : External Predictors of Lithium Response in Bipolar Disorder Therapeutic Advances in Chronic Diseases, 2(3): 209–226

Also see Lamotrigineplugin-autotooltip__plain plugin-autotooltip_bigLamotrigine

Lamotrigine is used as an anticonvulsant and mood stabilizer. Currently prescribed in cases of epilepsy, Lennox–Gastaut syndrome and bipolar disorder. Its active biochemical pathways are not known. more info at Wikipedia

"The action mechanisms underlying the mood-stabilizing effects of lamotrigine are unknown at present but recent studies have produced interesting leads. Lamotrigine modulates various ion channels, altering neuronal excitability. The use-dependent inhibition of neu… and Ketamineplugin-autotooltip__plain plugin-autotooltip_bigKetamine (treatment for depression)

The use of Ketamine to treat Major Depressive Disorder was formally investigated in a 2006 report for JAMA Psychiatry. A team based at the US National Institute of Mental Health (NIMH) in Bethesda, Maryland, found that :

"Robust and rapid antidepressant effects resulted from a single intravenous dose of an N-methyl-D-aspartate antagonist; onset occurred within 2 hours postinfusion and continued to remain significant for 1 week." and Major Depressive Disorderplugin-autotooltip__plain plugin-autotooltip_bigMajor Depressive Disorder

Major Depressive Disorder (MDD), also known simply as 'depression', is a mental disorder characterized by at least two weeks of pervasive low mood.

Current estimates are that severe depression affects around 2% of the global population at any given time, currently more than 150 million. The majority of cases don't appear to have an obvious personal and/or societal cause.