Depression affects many of us from time to time, but serious clinical depression is much less common, perhaps only affecting 3 - 5% of the population. The highest incidence is in women aged 35 – 45 years and it increases in men with age. Bipolar affective disorders such as Manic Depression are equally common in men and women although, overall, depression is twice as common in women. It is more common in social classes I, II and V and among the divorced or separated.