It's now been established in the medical community that both sexes experience the same symptoms (both physical, mental, emotional) when reproductive hormone levels decline. Hormonal levels decline in everyone due to the process that leads up to menopause in women & andropause or male menopause in men.
This natural decline in hormone levels can begin as early as age 5. All the symptoms that come with female menopause also occurr in men.
Because these symptoms involve many mental & mood & sleep changes, it is many times misdiagnosed as other conditions such as bipolar disorder.
For the latest information on this hormone level decline & it's symptoms, see these websites:
35 symptoms of menopause
Male menopause (andropause)
Male menopause article
The decline of reproductive hormones in everyone should be taken seriously. If you're having anything occurring, it can be traced down to this natural process.