Changes in learning, memory, and mood during lithium treatment. Approach to a research strategy.

In a double-blind study the effects of a 14-day lithium medication (dosage: 24 mval/day to 36 mval/day) were investigated. The subjects were 24 healthy male volunteers. The effect of lithium on their mood, ability to learn nouns, and memory of the words learnt was measured after 2 hours and 14 days. In spite of a relatively low mean plasma lithium level on the 14th day (0.54 +/- 0.15 mmol/l), the lithium volunteers assessed themselves after 2 weeks of treatment as significantly less relaxed, less active, less socially involved, more bored, and more tired than the placebo group. As to learning, the lithium group showed only a slight impairment of performance compared with the placebo groups. As to memory, there was a significant difference in free recall over 2 weeks: the lithium group remembered fewer words than the placebo group. Additional motivation of free recall over 2 hours was ineffective. It is discussed whether lithium changes spontaneous initial action and thereby the will to act. This could be interpreted as a change in the production of the characteristics of experience and behaviour.