At what age can a psychiatrist tell that a child has bi-polar?

Bipolar. As early as age 3. With careful assessment and observation, we can differentiate from hyperactivity or mood disorders. Also, strong family history of bipolar is suggestive.
I am aware of. One child that was diagnosed at age 2 years old. I would advise that bipolar disorder in young children can look quite different then bipolar disorder that begins in teens or adulthood. The diagnosis can be very difficult to make. I would encourage evaluation by a child psychiatrist or child psychologist in this situation. It sometimes take years to get the correct the diagnosis.