How Mice Are Helping Us Understand Bipolar Disorder

Bipolar disorder is very difficult to study for many reasons but one of which is because suitable animal models for bipolar disorder have not been found as they have been for depression. 

However, in 2007 an animal modal for mania was found. This manic animal was a mouse and the mania in that mouse was created by mutating the CLOCK (circadian locomotor output cycles kaput) gene (mentioned earlier, the CLOCK gene is associated with the circadian rhythm).

Mania in Mice

Building on research done with fruit flies, it was found that mutating the CLOCK gene produced mania in mice that included:

• hyperactivity
• decreased sleep
• lowered depression behavior
• lower anxiety
• increase in pleasure from cocaine, sugar and forebrain bundle stimulation (a reward and pleasure part of the brain)

Treating Mania in Mice

And if that were all we learned, it would be interesting, but not really earth-shattering. The truly earth-shattering part is that this mania can be effectively treated with lithium.
That’s right, we can identify the cause of mania (because we caused it) and then identify an effective treatment (lithium) leading us inexorably down the path of understanding how that treatment works on bipolar disorder. This truly is big news.

Substance Preference in Mice

It should also be noted that this mutation also seemed to encourage addition-creating behaviors in mice, possibly explaining the extremely high correlation between substance abuse and bipolar disorder.

Limitations

This information is very interesting and gives tremendous hope to those of us looking towards science to pinpoint the secrets of bipolar disorder. However, it should be remembered that what was produced was a persistent manic state and not a mood oscillating state as is seen in bipolar disorder. This means it’s likely that this information is only part of the puzzle of bipolar disorder and certainly not a complete key.

Hope from Bipolar Mice

Nevertheless, if we can break down the causes of bipolar, genetically, we have hope of correcting it either through gene manipulation or through medical intervention. Moreover, understanding better how lithium—our big gun in treating bipolar disorder—works, we can invent newer, more effective treatments for all those who can’t take lithium for a variety of reasons.

Right now I’d say we all owe a lot to the little, tiny mouse. He’s doing work that may go on to save the lives of people just like us.