The document discusses bipolar disorder, including its symptoms and potential biological causes. Bipolar disorder causes extreme shifts in mood from depression to mania. Studies show it can affect both adults and children. Possible biological causes include abnormal neurotransmitter levels and brain structure differences. Genetics also plays a role, as identical twins have a higher likelihood of both having the disorder. Effective treatment requires a combination of medication, typically lithium or antipsychotics, alongside psychotherapy. More research is still needed on therapy and determining the exact causes of bipolar disorder.