This article looks at Mark Rose’s review of the risk factors for depression. There are several risk factors for clinical depression. One of the major risk factors is simply being a woman. There is almost twice as much a lifetime prevalence of depression among women than men. Body mass index greater than 40, which constitutes severe obesity, is highly linked with depression. Poverty is a risk factor for depression among both genders.
“Depression” is a word which has long since entered our common parlance. But what exactly does it refer to? The DSM-5 has a list of disorders it labels depressive disorders, and says that what they have in common includes: “”presence of a sad, empty, or irritable mood, accompanied by somatic and cognitive changes that significantly affect a person’s ability to function.” Under the broad label of “depressive disorder” there is persistent depressive disorder, major depressive disorder, premenstrual dysmorphic disorder, and several others. A new disorder known as disruptive mood disorder has been introduced to avoid accidental misdiagnoses of bipolar disorder. It is characterized by chronic and severe irritability.
The “classic condition” of the depressive disorders is major depressive disorder. This disorder was once known simply as “clinical depression.” It is characterized by distinct episodes of depression lasting at last 2 weeks duration. These 2 week changes must involve obvious changes in emotion and cognition and there must be periods of remission between episodes. On the other hand there is persistent depressive disorder, which lasts longer and with fewer remission, but whose symptoms are comparatively mild. If the individual has a depressed mood that ocurs for most of the day, most of the time, for a period of 2 years (for adults, but one year for adolescents and children), they may qualify for a diagnosis of persistent depressive disorder.
Intense stress or loss during childhood and emotional trauma and physical abuse, are all risk factors for developing clinical depression. Having experienced loss in the form of either death or divorce, undergoing major life changes such as a job change, and experiencing a traumatic or violent event such as a car accident, are all risk factors for depression. The same is true of family psychopathology. Major depressive disorder is between 2 and 4 times more likely to occur if you have a first-degree biological relative, as opposed to the risk for the rest of the population. The evidence is complicated, however:
“Relative risks appear to be higher for early-onset and recurrent forms. However, family studies indicate that major depression is not caused by any single gene but is a disease with complex genetic features. No specific genetic risk factor has been reliably identified and associated with the development of depression.”
High levels of neuroticism, negative cognitive styles, excessive anxiety, and high levels of impulsivity and obsessionality can all predispose an individual to depression. Neurological illnesses such as seizure disorders, MS, Parkinson’s disease and stroke are also highly correlated with the onset of depression. Between 20-25 percent of those with either myocardial infarction, diabetes or cancer will experience major depressive disorder.
“Chronic pain, medical illness, and persistent or severe psychosocial stress elevate the risk of major depression, possibly explained by the negative impact of cortisol and other stress hormones on the neuronal substrate of mood in the central nervous system (CNS).”
The following factors predispose a women to developing postpartum depression:
“Depression or anxiety during pregnancy:
Previous history of a mood disorder
Low levels of social support,
Stressful life events
Pre-pregnancy and gestational diabetes
Fragmented or poor sleep
Current or past experiences of abuse
Difficulty breastfeeding in the first two months postpartum.”
Between 40-60 percent experience a major life event or psychostressor which precipitates full-blown depression. For a few months after the event, anxiety and mild depression may persist for months before the onset of a major depressive episode. The average age is around the mid-20s. The average duration of a depressive episode of those with the disease may be 6 months or longer. Remission is defined as 2 or more months with, at most, only one or two symptoms to a mild degree. Some never experience full remission whereas others may go years between episodes. Those with chronic depression are more likely to have underlying anxiety, substance misuse or personality problems than the healthy population.
“Recovery typically begins within 3 months of onset for 40% of individuals with MDD and within 1 year of onset for 80% of individuals. Persons with recent-onset MDD are more likely to experience near-term recovery, and many individuals who have been depressed only for several months can be expected to recover spontaneously. The risk of recurrence becomes progressively lower over time as the duration of remission increases. Preceding severe depressive episodes, younger age, and previous multiple depressive episodes increase the risk of recurrence.”
Recurrence is helpfully treated by antidepressants. Such treatment is reduced by 70 percent for 3 years after a recent episode. There is an average recurrence on placebo of 41 percent as opposed to active treatment, which is 18 percent. Remaining under active treatment is important, as there is a 77 percent increase in risk of relapse or recurrence if the individual discontinues the medication. Antidepressants are especially effectively with regular follow-up in a collaborative care setting. This can helpfully curb medication non-compliance.
Repeated episodes of MDD may foreshadow more in the future. For example, one episode of major depression is associated with a 50 percent chance of another, two episodes with 70 and 3 or more with 90. Higher numbers of episodes also anticipate inadequate response or non-response. Tragically, between 12-20 percent of those with a mood disorder will commit suicide, with the first 3 months being the period of highest risk for a first attempt. The following 3 months constitutes the second highest risk period.