Depression and bipolar disorder are virtually never diagnosed together in the same person at the same time. Both are serious mental disorders that have many treatment options available to a person diagnosed with one of them. However, the treatments between depression and bipolar disorder are usually quite different, and the wrong diagnosis could start a person down a road of frustration with their treatment, because they feel no improvement in their symptoms.
Depression is a necessary component of bipolar disorder, and because of that, sometimes people can be misdiagnosed with having clinical depression rather than bipolar disorder. For instance, if a person is experiencing a depressed mood, they may seem to have no sign of energy or mania commonly associated with someone who has bipolar disorder. Some general practitioners and even mental health professionals may not probe enough during the initial clinical interview to ensure the person doesn’t have a history of such mania, or other symptoms that might suggest such a past manic episode or hypomanic episode. When depression occurs in the context of bipolar disorder, it’s sometimes referred to as “bipolar depression.”
The opposite can occur as well. Someone who has been diagnosed with bipolar disorder may actually have clinical depression instead, because of a mental health professional’s decision about what constitutes a manic or hypomanic episode. Some clinicians will be very aggressive in diagnosing a hypomanic episode (basically, a less severe type of mania), while another clinician might write off a single episode as a part of being a young adult, intoxicated, or some other external factor.
Generally, mental health professionals try to find the best diagnosis that fits within the client’s presenting picture, and to err on the side of caution when it comes to multiple diagnoses. Multiple diagnoses complicate treatment options, and often confuse the issue of what is the primary problem in the person’s life. A thorough mental health professional will ask multiple probing questions surrounding possible past manic or hypomanic episodes in a person’s life if they present only with depression. The same is true if someone comes to a professional in a seeming hypomanic episode.
The key is for the mental health professional to ask the right questions and for you to be honest with them to find the right diagnosis that fits your symptoms. The right diagnosis means it is more likely you will receive beneficial treatments for the disorder sooner, and subsequently feel better more quickly as well.