In the past, bipolar depression and ordinary depression were thought to be the same. But a growing body of research shows that there are significant differences between the two, especially since the treatments are completely different. Antidepressants do little to help bipolar depression, but instead can trigger mania or hypomania, lead to a rapid cycle of bipolar disorder, or interfere with the efficacy of other mood stabilizing medications. Common symptoms of bipolar depression include: 1. feeling hopeless, sad, or empty. 2, irritability 3, inability to experience pleasure 4, fatigue, low energy or loss of energy 5, mental sluggishness 6, changes in appetite or weight 7, sleep problems 8, concentration and memory problems 9, feelings of worthlessness or guilt 10, thoughts of death or suicide