Hello Adi,
This is quite common in the age group of your grand father so don't get worried about that. Duralith is very effective in treatment of bipolar disorder also known as manic disorder. Duralith is also known as lithium carbonate and Priadel. This drug is helpful in reducing frequency and severity of depression and manic disorder. The effects of this drug depend on individuals and results vary from person to person. Lithium changes sodium movement in nerve cell, Cause a shift toward intraneuronal metabolism of catecholamine. However the specific mechanism of action of lithium in bipolar disorder is under research and still unknown. I think this much information iis enough for you, however if you want to get more information you can search it in Google.