Not all depression is alike. Here are the differences.

Adapted from Understanding Antidepressants.

In his often-quoted beginning of Anna Karenina, Tolstoy wrote, “All happy families are alike; each unhappy family is unhappy in its own way.”  If we stretch this notion a little — going from families to individuals, and from unhappiness to depression — we come up with an interesting question, which is the subject of this blog: Are persons with depression all alike, or is each depressed in his/her own way?  In one sense, the answer seems to be that the difficult experience of depression is unique to each person, affected by age, past experiences, beliefs, hopes, methods of dealing with stress, and many other factors. In another sense, though, there may be a useful middle ground, recognizing both the uniqueness of the individual but also that there may be some general qualities that depressed persons may have in common.  This view, somewhere in the middle between the individual approach and the other extreme which is that all depression is alike, suggests that there are several general types of depression.  It’s useful to understand them, as they differ in appearance and understanding them can help in the selection of the best treatments.

Let’s look at some of  them:

Persistent depressive disorder. This condition, previously called dysthymia, is characterized by its chronic nature, continuing almost every day for over two years.  In addition to depressed mood and pessimistic thinking, there is often low motivation to do things and decreased ability to experience pleasure.  Unlike major depression, which may have a larger number of symptoms and in which a person may have periods of normal mood between episodes of depression, this is a day-in-day-out condition. It is treated with the same medications, though it is noted that SSRIs and monoamine oxidase inhibitors may be more beneficial.

Premenstrual dysphoric disorder (PMDD). In about 5 percent of women, the whole range of depressive symptoms may appear for a few days preceding menses.  There are some data to suggest alterations in serotonin function during this period, and a common treatment is to use SSRIs.  It is not entirely clear whether it is better to treat throughout the month or just during the few days of symptoms.  Since most antidepressants take some time to show effectiveness, and since most forms of depression need longer-term medicine, many psychiatrists prefer to treat throughout the month.

Major depression or dysthymia with a seasonal pattern (seasonal affective disorder or SAD). About 10 to 20 percent of persons with recurrent depression experience worsening in one season, usually the winter.  This appears to be related to decreased amount of exposure to sunlight, and indeed its frequency is much higher in New Hampshire (9.7 percent), for instance, compared to Florida (1.4 percent) in one study.

Seasonal affective disorder is more common in young adults and in females. One aspect of its physiology seems to be related to dysfunction of the serotonin system, and it may involve a delay in the sleep-wake cycle relative the timing of daylight.  Treatment is usually with SSRIs, and bright light therapy.  This is done by sitting in front of cool white or full spectrum fluorescent lights with ultraviolet shielding, for 30-60 minutes a day over a period of several weeks. Sometimes seasonal mood changes can be part of bipolar illness, which should be considered and ruled out, as bright light treatment could potentially increase the risk of manic episodes if bipolar illness should be present.

Major depression or dysthymia with atypical features. The use of the word “atypical” may be a little misleading, as 15 to 20 percent of persons with depression may have the additional qualities of fatigue, weight gain, increased sleep and carbohydrate craving.  Mood may be very sensitive to life events (“mood reactivity”), and in contrast to typical major depression, may briefly respond positively to happy events.  Persons with atypical depressions also tend to be very sensitive to rejection, and respond strongly to perceived rejections.

Psychotic features. As many as 15 to 19 percent of persons with major depression can have delusions or hallucinations.  Feelings of guilt or worthlessness, for instance, may be so strong as to form elaborate fixed beliefs, or a person may hear voices saying that they are worthless. There can be difficulties with thinking processes.  Psychotic features are of some concern, for several reasons. Firstly, there may be a higher risk of suicide.  Secondly, either antidepressants or antipsychotic medications alone may be insufficient, and usually a combination of the two is needed.

Depression with peripartum onset. Post-partum depression, appearing in the first four weeks after childbirth, occurs in 10 to 15 percent of women; in 40 to 50 percent, the symptoms began during pregnancy.  It is common in women with a prior history of major depression, and risk factors include a family history of postpartum depression, younger age and lack of support networks.  It is also very common in women with major depression who stop their medicines when becoming pregnant, occurring in up to 70 percent, about twice the rate for women who continued with medicines. In evaluating whether to use medicines during pregnancy, the risks of adverse effects on the child (which possibly include a small increase in cardiac malformations, among others) need to be weighed against the risks of untreated depression in the expectant mother.  The latter can include low birth weight, premature birth, and poorer quality prenatal care.  In the postpartum period, most antidepressants can appear in milk, and this concern should be considered in making medication decisions.

Bipolar disorder. Bipolar disorder is not one of the depressive disorders, but is considered a separate category of illness.  In its clearest form (“bipolar I”), a person has a history of fairly clear manic and depressive episodes. Periods of mania are characterized by euphoric or irritable mood as well as a variety of other symptoms that can include very little need for sleep, rapid speech and racing thoughts, grandiosity, and reckless or impulsive behavior.  While these may be fairly obvious, another form (“bipolar II”) involves depressive episodes, but the manic periods are less clear (“hypomania”), often involving times of abundant energy and little need for sleep, with irritability or grandiose thinking, lasting at least several days. Another related condition is cyclothymic disorder, in which a person has at least a two-year history of alternating depressive and hypomanic periods which are milder and do not meet the full criteria for either condition.

If bipolar illness is present, antidepressants alone are unlikely to help the depression, and may increase the risk of having a manic episode or rapidly alternating depressive and manic episodes.   Bipolar illness also has its own, very different, set of treatments. For these reasons, it’s always important to keep the possibility of unrecognized bipolar depression in mind.

The important thing to remember, then, is that all depression is not alike.  It’s useful to consider these different kinds, as some may be benefited more by particular types of antidepressants, by adding additional therapies (for instance, bright light treatment), or (in the case of bipolar depression) using entirely different types of medicines.

Wallace B. Mendelson is a psychiatrist and author of Understanding Antidepressants.

Image credit: Shutterstock.com

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