Reproduction hormone levels can decrease in humans as early as the age of 5, with a slow decline as people age. Testosterone in men & estrogen in women are both affected. In women this natural event is called menopause & perimenopause, in men it's called andropause (or male menopause, the equivelant to menopause in females). During this decline in reproductive hormones both sexes can get the same symptoms as menopause in women, such as mood swings, irritability, anxiety, hot flashes, depression, insomnia and/or other sleeping problems, etc.
The same symptoms of bipolar can also be produced by this reproductive hormonal decline. This is where the subject of bipolar misdiagnosis comes into light. Because the symptoms of hormonal decline in the sexes look like bipolar illness, it can be misdaignosed.
Here are some websites for reference that will provide information on the hormonal declines in both sexes, the symptoms, and other related material.
35 symptoms of menopause (in women)
Male menopause, same symptoms as female menopause (can begin as early as age 20, some even earlier)
For information on misdiagnosis as well as explaining the psychotic symptoms sometimes seen with bipolar illness (also hormonal caused)
Bio on author: I'm a medical researcher & scientist with years of work in the psychiatric & medical fields. I've provided this infomation is based on years of study & research & I'm posting it here in hopes in will be of assistance to anyone who reads this.