GSK-3 transgenic mice were demonstrated to be hyperactive (Prickaerts et al., 2006), and this is encouraging as GSK-3 is inhibited by lithium and GSK-3 heterozygote knockout mice appear to have a number of behaviors resembling lithium treated animals (O’Brien et al., 2004). Yet, GSK-3 pharmacological inhibition was reported to have more antidepressant- than manic-like effects (Gould et al., 2004), and further work is clearly needed to evaluate a large range of behaviors in these mutant mice and their response to existing medications. In summary, none of these mutants is, at this time, adapted as a commonly used model, not even for specific facets of the disease. This may be because of the relatively short time since the development of these mutants but may also be the consequences of the hindering factors related to working with mutants as described above.