The main difference between bipolar disorder and depression is the age of onset of symptoms.

The statement that the main difference between bipolar disorder and depression is the age of onset of symptoms is not accurate, which is why the answer is false. The primary distinguishing feature between bipolar disorder and depression lies in the presence of manic or hypomanic episodes in bipolar disorder, which are not found in unipolar depression. In bipolar disorder, individuals experience extreme mood swings that include episodes of heightened mood, increased energy, and impulsive behavior, known as mania or hypomania, alongside depressive episodes.

Conversely, major depressive disorder, simply referred to as depression, is characterized solely by prolonged periods of low mood without the manic phases. While age of onset can vary for both conditions, it is not the defining characteristic that separates them. Recognizing these distinct mood patterns is crucial for accurate diagnosis and treatment, emphasizing that the nature of the mood episodes themselves is the key difference rather than the age at which they arise.