Table 1 Summary of lithium efficacy and safety at different dose ranges

‘High’ dose

> 1.0/1.2mmol/L

0.8-1.0mmol/L

> 250 mg

Severe non-responsive acute mania, aggressive / self-harm behaviour

Non-responsive BD if well tolerated

Increased risk of toxicity

Long-term: increased safety concerns vs. below

‘Therapeutic’ dose

0.6–0.8 mmol/L

~ 112-250 mg

Maintenance BD (also shorter-term depression, mania), rapid cycling BD, suicidality, unipolar depression, possible effect dementia.

Short-term side effects common. Long-term some risk to renal +/ thyroid function. Many concerns addressed via monitoring +/ action.

‘Low dose’

0.2–0.6 mmol/L

~ 20-100 mg

Possible effect dementia; possible effects as adjunct in depression, mania, limited evidence for other neuropsychiatric benefits.

Generally well tolerated, attenuated concern relative to above.

‘Micro’ dose

Unknown

~ 5-20 mg

Limited evidence for effects on mood, anxiety and dementia over long periods.

No known safety concerns.

‘Trace’ dose

< 0.1mmol/L

< 5 mg

Possible small effect over long periods- suicide, dementia, ?homicide.

No safety concerns