Scientists are beginning to realise that although this is a genetic disease, this is not the only cause of bipolar. Many outside factors have a say and can trigger it off. Genetically, a predisposition of bipolar is passed on through the default in numerous genes and the brain is therefore defective and vulnerable. Usually though, bipolar will not show itself until a factor triggers it off and causes the defective genes to come together. Studies have shown that genetic predisposition to depression may be linked with an abnormal sensitivity to the neurotransmitter acetylcholine.
New studies of the brain are being carried out via magnetic resonance imaging (MRI), positron emission tomography (PET), and functional magnetic resonance imaging (fMRI). As differences between brain patterns of that in a healthy person, to one with bipolar become clearer, hopefully, there will be new leads on improving treatment.