Rates of diagnosable depression and subclinical symptoms of depression (i.e., symptoms that are not severe enough to receive a diagnosis) are quite high in the general population. These rates are increasing, especially among young adults.

Nearly 25 percent of women experience a major mood disorder at some point — most commonly during the teenage to early adult years. Fifteen percent of men experience a diagnosable mood disorder during their lifetimes. Current diagnoses of depression during the past month are also high, with major depressive episodes reported by six percent of women and four percent of men.

Depression is especially prevalent among women of child-bearing age. Approximately eight percent of mothers are clinically depressed. This rate increases to 12 percent of mothers of newborn babies.

Prevalence rates of subclinical depression are also high in the general population, with 24 percent of people experiencing at least two depressive symptoms for at least two weeks during their lifetimes.

The course of depression can vary widely. Individuals who suffer from clinical depression experience five to six episodes on average, meaning that young mothers who have had one depressive episode are at high risk for recurrences, potentially exposing families to repeated bouts of depression. Most episodes last six to nine months, although 20 percent last for two years or more. Chronic depressive symptoms are usually more severe and debilitating. Approximately 40 percent of individuals who seek treatment have “double depression,” suffering from both dysthymia and major depression.

Depression may be experienced differently by individuals. One person may become withdrawn, tearful and quiet, while another person may become irritable, complaining and demanding. Depressed adults report more negative thoughts and maladaptive coping, worse role functioning, and poorer physical and social adjustment.

Depressed individuals tend to marry partners who experience psychological difficulties or have family histories of mental illness, making depressive symptoms more severe and marital and family disturbances more likely. This leaves children at high risk for poor parenting from both parents.

Major depression frequently co-occurs with other psychological disorders including anxiety disorders, substance abuse disorders, eating disorders, attention deficit disorder, and schizophrenia, all of which complicate the course of depression and diminish performance in primary roles including parenting. A study of consecutive hospital admissions found that 35 percent of depression patients were also diagnosed with a personality disorder.

— Dr. Patricia Turner, Registered Psychologist, Calgary, Alberta