Proposing the sweet solution preference test as a screening assay for anti-manic effects of mood stabilizers

There is a desperate need for in-vivo behavioral screening tests for anti-manic effects. The frequently used psychostimulant-induced hyperactivity test appears to have lower validity than previously described, but other quick, simple and high throughput tests are currently unavailable.

In the context of modeling the behavioral facets of mania, we previously suggested that the sweet solution preference test (SSP) in naive mice might have predictive validity for screening anti-manic effects. The current study further examined this proposal by testing the effects of lithium, valproate and imipramine on SSP in three strains of mice (male mice from the black Swiss, ICR and C57bl/6 strains) and an exploratory test in females (black Swiss strain).

Data demonstrate that lithium and valproate at appropriate dosing schedules significantly and reliably reduce SSP in all three strains (including in females) but that the antidepressant imipramine has no effects.

The results support the utilization of the SSP as mice screening model for anti-manic effects of drugs with stronger predictive validity compared with other methods.

The SSP is not a comprehensive model for bipolar disorder but it has good predictive validity and strong practical value that can be applied towards simple and fast screening of large numbers of animals, without the need for specialized equipment or complicated/prolonged procedures. We therefore propose that the SSP is an advantageous screening assay for testing novel mood stabilizing drugs for anti-manic properties.