Bipolar affective disorder or manic -depressive psychosis (MDP) is a mood disorder affecting 2.4% of the global population . Lithium is considered as the "gold standard" for the treatment of bipolar disorder but the clinical use of lithium is often restricted due to its narrow therapeutic range and adverse effects.

In a published case report, Bleiwiss H found that sodium chloride supplementation diminished the adverse effects caused by lithium The literature search also revealed that till date, there is no published clinical study evaluating the effect of dietary intake of sodium in preventing the fluctuations of serum lithium level and lithium toxicity Therefore, a randomized clinical trial has been designed to evaluate the effect of regulated add -on dietary sodium chloride on serum lithium levels in bipolar disorder.

Bipolar affective disorder or manic -depressive psychosis (MDP) is a mood disorder affecting 2.4% of the global population. Lithium is considered as the "gold standard" for the treatment of bipolar disorder but the clinical use of lithium is often restricted due to its narrow therapeutic range and adverse effects.One of the major adverse effects of lithium is nephrogenic diabetes insipidus which is due to long -term renal dysfunction.

In the initial months of lithium therapy, psychiatrists face difficulty in titrating the dose and stabilizing serum lithium level and this fluctuation of serum lithium level may be due to a lithium-induced sodium depleted state.

In a published case report, Bleiwiss H found that sodium chloride supplementation diminished the adverse effects caused by lithium. 8 In another case report, Tomita et al demonstrated that the change in sodium chloride intake can bring about changes in serum lithium and help in stabilizing the levels of serum lithium concentration.

As all the case reports are from abroad, the effect of dietary sodium on serum lithium level among Indian population is completely unknown. The literature search also revealed that till date, there is no published clinical study evaluating the effect of dietary intake of sodium in preventing the fluctuations of serum lithium level and lithium toxicity. Therefore, a randomized clinical trial has been designed to evaluate the effect of regulated add -on dietary sodium chloride on serum lithium levels in bipolar disorder. This study may help to explore the role of add -on sodium chloride in decreasing the fluctuations in the serum lithium level and improving the clinical outcome of patients with bipolar disorders.

Inclusion Criteria:

• Patients aged 18 -60 years, of either sex with the clinical diagnosis of bipolar disorder (DSM V) who are on maintenance lithium therapy for ≥ 1month and ≤ 6 months.
• Patients with normal serum sodium level (135 -145 mEq/L) and serum lithium in the optimum therapeutic range (<0.6 mEq/ L or >0.8 mEq/ L) .

Exclusion Criteria:

• Patients with comorbidities like other psychiatric disorder s, organicity, substance abuse, personality disorder, intellectual disability and other neurotic disorders .
• Patients with any renal, cardiovascular, neurologica l, endocrinal and hepatic dysfunction.
• Patients suffering from diarrhoea, dehydration
• History of any invasive neurosurgical/ non -invasive neuropsychiatric procedure.
• Medication history of psychoactive or central nervous system depressant drugs.
• Patients who are on NSAIDs, ACE inhibitors, antiarrhythmics, diuretics and neuromuscular blocking agents .
• Pregnant and nursing women .
• Patients with drug/alcohol abuse.