There are various forms of depression - the most common of which is 'reactive' depression, triggered by an emotional trauma or similar cataclysmic event - bereavement etc. The reaction causes a feeeling of isolation, hopelessness, disconnection, loss of energy, appetite, libido, and similar symptoms. Manic depression is different - it is often caused by a chemical imbalance within the brain, and causes frequent and excessive changes in mood - hyperactivity, talking excessively, quickly, and at volume, urges to complete impossible tasks - spring cleaning a house in an hour etc. The condition also produces excessive euphoria, and feelings of invincibility. The reverse mood swings, which occur without warning or pattern, reduce the sufferer to anything decending into a catatonic state, and embracing all the previous depressive symptoms. Happily, modern medical understanding, and treatment, are increasingly sophisticated, and both conditions can be controlled by appropriate medication, and counselling, if necessary. Anyone suffering from, or knowing someone who suffers from these symptoms, should contact their GP for advice.