ABSTRACT
Depression is an illness that involves feelings of sadness lasting for two weeks or longer, often accompanied by a loss of interest in life, hopelessness, and decreased energy. It is a medical illness linked to changes in the biochemistry of the brain. Lithium is used for acute mania or prevention of recurrences of bipolar manic-depressive illness in adults. Lithium is a toxic drug and not metabolized in the body. Twenty patients with manic depression, 5 with hypomania and 5 hysteria were taken in the study. Effect of lithium on biochemical parameters like serotonin [5'hydroxy tryptamine], CPK and lithium were determined. Lithium treatment when applied to patients suffering from depression increases level of 5'HT, which is beneficial. However, increase in levels of serum CPK and lithium also occurs which may be toxic. Hence care needs to be taken in treatment to avoid brain damage to patients. It is therefore concluded that during lithium treatment careful monitoring of lithium blood level must be done to ensure adequate therapeutic efficacy without toxicity