Depression is a recognized mental health disorder that affects millions of individuals across the globe. But while major depressive disorder, or MDD, is perhaps the most studied and treated mental health disorder, other types of depression have also been recognized by leading mental health organizations, such as the American Psychiatric Association (APA).
A Depressive Family Emerges, and a Mental Health Continuum is Formed
Depression is one of the earliest mental health conditions to be recognized, with symptoms such as a low mood, an unrelenting sadness without necessitating a definitive cause, and a pervasive lack of energy, recognized as key features of depressive conditions. But while depression has been referenced as its own mental health disorder, official disorders manuals had listed depressive disorders as part of the more general mood disorders family, which also included bipolar disorders.
One example of this is the APA’s Diagnostic and Statistical Manual, whose fifth and latest edition (the DSM-V) was published in 2013. Prior to this edition, the APA tended to classify patients who suffer from a break from reality as battling a psychotic disorder, and those with a firmer grip on reality as suffering from a mood disorder.
The DSM-V changed all of that, by separating the mood disorders chapter into two, distinct categories: the bipolar family and the depressive family. As a result, a spectrum of sorts was created, moving from psychotic features, to bipolar disorders, to depressive disorders. This continuum was based on more recent discoveries that found common genetic, neurocognitive, and pharmacological associations between psychotic and bipolar disorders. Both of these disorder groups were found to appear in patients’ family histories, their presenting symptoms, and their response to antipsychotic agents.
Bipolar and depressive disorders also share central key features, namely the presentation of a depressed mood, comorbidity, family history and a tendency to episodic (as opposed to chronic) manifestation.
Taken together, these discoveries placed bipolar disorders between the hallucinatory, often manic psychotic disorders, and the internalizing shutdown mechanism that commonly appears in depressive disorders.
An important note: As a general rule, bipolar disorders feature a combination of depressive episodes with at least one manic episode of high-energy, extremely joyous, or euphoric feelings, sometimes appearing together with megalomania. Bipolar disorders should not be viewed as necessarily having “psychotic-like” conditions, nor should they be viewed as warning signals for an impending psychotic episode.
The Depressive Disorders Family
Now featured as their own category, the conditions listed under the depressive disorders family were primarily defined by severe sadness, low mood, and irritability, which together significantly affect the patient’s daily functioning.
In addition to several types of “unspecified” diagnoses, the depressive disorders family includes the following conditions:
- Disruptive Mood Dysregulation Disorder. This childhood disorder is listed first among the depressive disorders, due to its shared features with the previous family of bipolar disorders. Disruptive mood dysregulation disorder is mainly defined by sharp pangs of anger and irritability, at times leading to temper outbursts that fall short of a manic episode. This disorder includes temper outbursts that do not meet the diagnostic criteria of either a manic episode or conditions belonging to the bipolar disorder family. This disorder was included in the depressive family since research has found that children who receive this diagnosis are more likely to develop a depressive disorder as adults than they are to develop a bipolar disorder.
- Major Depressive Disorder. The pièce de résistance of the depressive disorders family, major depressive disorder is the central condition around which the entire category is built. It is defined as a deep, consistent sadness that weighs down in the individual. Additional, key features include a general lack of energy, a feeling of hopelessness, irritability, emptiness, and a feeling that something important, yet not necessarily clear, has been lost to them. Major depressive disorder is more likely to appear as moodiness among children and adolescents than it is among adults. It can severely affect one’s quality of life, causing them to become isolated from others, neglect themselves and at times attempt or take their own lives.
- Persistent Depressive Disorder (Dysthymia). The most chronic cases of depression receive this diagnosis, which combines two former diagnoses—persistent (major) depression, and the less severe dysthymia. Simply put, persistent depressive disorder should be considered in long-term cases of depression, whether the severity meets the criteria of major depression or not.
- Premenstrual Dysphoric Disorder. With over two decades of research to back up this female-centric condition. The majority of premenstrual dysphoric disorder cases are marked by affective lability, high levels of irritability, and a generally anxious or depressed mood before the onset of menstruation. A complete absence of symptoms often occurs in the days following menstruation.
Additional Depressive Signifiers
In addition to the above-mentioned diagnoses, the DSM-V includes a number of signifiers, which help further identify the specific manifestations of clinical depressive experiences. They include:
- Treatment-Resistant Depression. Cases of major depressive disorder are usually considered “treatment-resistant” when a minimum of two antidepressant medications have either been found ineffective in alleviating their symptoms or too adverse for the patient to continue taking. Over 40% of patients with major depression are considered treatment-resistant.
- Postpartum Depression. A major depressive episode can be considered to be postpartum depression if it appears during a woman’s pregnancy or within the first four weeks following delivery. It is generally marked by feelings of sadness, emptiness, a sense of lacking and a low mood that all affect her ability to function in conjunction with her pregnancy or delivery. A number of risk factors for postpartum depression have been identified:
- Peripartum (prenatal) anxiety or depression.
- Mood swings, crying spells, and irritability following childbirth, which collectively are often referred to as “baby blues.”
- The hormonal and physical changes due to childbirth.
- A poor, unsatisfactory relationship with the baby’s father.
- A non-functioning support system for the mother.
- A low level of self-esteem.
- Stress due to the infant’s temperament.
- Seasonal-Related Depression. This specifier’s central feature is the recurrent appearance of major depression during a certain time of year. While most cases of seasonal-related depression occur during the winter months, this is not always the case. A second association has been found between higher rates of seasonal-related depression and living at higher latitudes. Empirical evidence points to a decrease in exposure to sunlight as the cause for this subtype of depression: since sunlight helps regulate the secretion of the mood-elevating neurotransmitter serotonin, less sunlight is thought to disrupt its regulation, causing depressive symptoms to appear. A mood-elevating neurotransmitter, serotonin is kept active for longer during summer, thanks to the increase in sunlight. Season-related depression is also four times more common among women than men: studies suggest this is due to fluctuating hormonal levels, particularly estrogen.
- Catatonia. Depressive disorders can also be marked by disrupted psychomotor functions, which make up the key feature of catatonia. Decreased motor activity, unresponsiveness or immobility, mutism, “waxy” movement, excessive movement, or agitation can all signal catatonia.
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