Clinical depression is a state of intense sadness, melancholia or despair that has advanced to the point of being disruptive to an individual's social functioning and/or activities of daily living. A person suffering from depression may feel tired, sad, irritable, lazy, unmotivated, and apathetic. Clinical depression is generally acknowledged to be more serious than normal depressed feelings. It often leads to constant negative thinking and sometimes substance abuse. Extreme depression can culminate in its sufferers attempting or committing suicide.
Without careful assessment, delirium can easily be confused with depression and a number of other psychiatric disorders because many of the signs and symptoms are conditions present in depression, as well as other mental illnesses including dementia and psychosis.
Types of depression:
Major clinical depression:
Major Depression, or, more properly, Major Depressive Disorder (MDD), is characterized by a severely depressed mood that persists for at least two weeks. Major Depressive Disorder is specified as either "a single episode" or "recurrent"; periods of depression may occur as discrete events or recur over the lifespan. Episodes of major or clinical depression may be further divided into mild, major or severe. Where the patient has already had an episode of mania or markedly elevated mood, a diagnosis of bipolar disorder (also called bipolar affective disorder) is usually made instead of MDD; depression without periods of elation or mania is therefore sometimes referred to as unipolar depression because the mood remains on one pole. The diagnosis also usually excludes cases where the symptoms are a normal result of bereavement. Diagnosticians recognize several possible subtypes of Major Depressive Disorder. ICD-10 does not specify a melancholic subtype, but does distinguish by presence or absence of psychosis.
Dysthymia is a long-term, mild depression that lasts for a minimum of two years. There must be persistent depressed mood continuously for at least two years. By definition the symptoms are not as severe as with Major Depression, although those with Dysthymia are vulnerable to co-occurring episodes of Major Depression. This disorder often begins in adolescence and crosses the lifespan. People who are diagnosed with major depressive episodes and dysthymic disorder are diagnosed with double depression. Dysthymic disorder develops first and then one or more major depressive episodes happen later.
Bipolar I Disorder is an episodic illness in which moods may cycle between mania and depression. In the United States, Bipolar Disorder was previously called Manic Depression. This term is no longer favored by the medical community, however, even though depression plays a much stronger (in terms of disability and potential for suicide) role in the disorder. "Manic Depression" is still often used in the non-medical community. Bipolar II Disorder is an episodic illness that is defined primarily by depression but evidences episodes of hypomania.
Postpartum Depression or Post-Natal Depression is clinical depression that occurs within two years of childbirth. Owing to physical, mental and emotional exhaustion combined with sleep-deprivation, motherhood can "set women up", so to speak, for clinical depression.(Kathy,2005)
Premenstrual dysphoria is a pattern of recurrent depressive symptoms tied to the menstrual cycle. The premenstrual decline in brain serotonin function is strongly correlated with the concomitant worsening of self-rated cardinal mood symptoms.(Eriksson et al , 2006) Of considerable clinical importance, the recent understanding of premenstrual dysphoria as depression points directly to effective treatment with Selective serotonin reuptake inhibitor (SSRI) antidepressants. Previously, disrupting ovarian cyclicity had been the only recognized treatment. A recent review of studies of a number of SSRIs has revealed that they can effectively ameliorate symptoms of premenstrual dysphoria and may actually work best when taken only during the part of the menstrual cycle when dysphoric symptoms are evident.
Recurrent brief depressive disorder (or recurrent brief depression) is in the ICD-10 classification. It is described as meeting the criteria for a mild, moderate or severe depressive episode; the depressive episodes have occurred about once per month over the last year; individual episodes last less than two weeks (typically less than 2-3 days), and they do not occur solely in relation to the menstrual cycle. Some people are at risk of self-harm, as well as the disruption to everyday life, particularly work
Physiological causes
Genetic predisposition
The tendency to develop depression may be inherited: according to the National Institute of Mental Health there is some evidence that depression may run in families, though this familial trend probably includes both biological and environmental factors.
Neurological:
Many modern antidepressant drugs change levels of certain neurotransmitters, namely serotonin and norepinephrine (noradrenaline). However, the relationship between serotonin, SSRIs, and depression usually is typically greatly oversimplified when presented to the public, though this may be due to the lack of scientific knowledge regarding the mechanisms of action. Evidence has shown the involvement of neurogenesis in depression, though the role is not exactly known.(Castren,2005). Recent research has suggested that there may be a link between depression and neurogenesis of the hippocampus. This horseshoe-shaped structure is a center for both mood and memory. Loss of neurons in the hippocampus is found in depression and correlates with impaired memory and dysthemic mood. That is why treatment usually results in an increase of serotonin levels in the brain which would in turn stimulate neurogenesis and therefore increase the total mass of the Hippocampus and restores mood and memory, therefore assisting in the fight against the mood disorder.
In about one-third of individuals diagnosed with attention-deficit hyperactivity disorder (ADHD), a developmental neurological disorder, depression is recognized as comorbid Dysthymia,(Hallowell,Edward and Ratey,2005) a form of chronic, low-level depression, is particularly common in adults with undiagnosed ADHD who have encountered years of frustrating ADHD-related problems with education, employment, and interpersonal relationships
Medical conditions
Certain illnesses, including cardiovascular disease(Maney and Maney,2004) hepatitis, mononucleosis, hypothyroidism, and organic brain damage caused by degenerative conditions such as Parkinson disease, Multiple Sclerosis or by traumatic blunt force injury may contribute to depression, as may certain prescription drugs such as hormonal contraception methods and steroids.
Dietary
The increase in depression in industrialised societies has been linked to diet, particularly to reduced levels of omega-3 fatty acids in intensively farmed food and processed foods(Felicity,2004) This link has been at least partly validated by studies using dietary supplements in schools and by a double-blind test in a prison. An excess of omega-6 fatty acids in the diet was shown to cause depression in rats.Depression can also be caused by a magnesium deficiency or lower magnesium levels.
Sleep quality
Poor sleep quality co-occurs with major depression. Major depression leads to alterations in the function of the hypothalamus and pituitary causing excessive release of cortisol which can lead to poor sleep quality. Individuals suffering from Major Depression have been found to have an abnormal sleep architecture, often entering REM sleep sooner than usual, along with highly emotionally-charged dreaming. Antidepressant drugs, which often function as REM sleep suppressants, may serve to dampen abnormal REM activity and thus allow for a more restorative sleep to occur.
Seasonal affective disorder
Seasonal affective disorder (SAD) is a type of depressive disorder that occurs in the winter when daylight hours are short. It is believed that the body's production of melatonin, which is produced at higher levels in the dark, plays a major part in the onset of SAD and that many sufferers respond well to bright light therapy, also known as phototherapy.
Psychological factors
Low self-esteem and self-defeating or distorted thinking are connected with depression. Although it is not clear which is the cause and which is the effect, it is known that depressed persons who are able to make corrections in their thinking patterns can show improved mood and self-esteem (Cognitive Behavioral Therapy). Psychological factors related to depression include the complex development of one's personality and how one has learned to cope with external environmental factors such as stress.
Early experiences
Events such as the death of a parent, issues with biological development, school related problems, abandonment or rejection, neglect, chronic illness, and physical, psychological, or sexual abuse can also increase the likelihood of depression later in life. Post-traumatic stress disorder (PTSD) includes depression as one of its major symptom.
Life experiences
Job loss, poverty, financial difficulties, gambling addiction, long periods of unemployment, the loss of a spouse or other family member, rape, divorce or the end of a committed relationship, involuntary celibacy, inability to have proper sex or premature ejaculation or other traumatic events may trigger depression. Long-term stress at home, work, or school can also be involved.
Evolution: Potential adaptive advantages of clinical depression:
Evolutionary analyses examine the ways in which depression as a response to certain environmental stimuli may act as an adaptive advantage and increase genetic fitness, either of the individual or the society as a whole.
Treatment
Treatment of depression varies broadly among individuals. The level, type, and methods of intervention vary dramatically. There are two primary modes of treatment that are typically used in conjunction; medication and psychotherapy. A significant number of recent studies have indicated that changes in lifestyle such as regular exercise and dietary supplements have beneficial effects.(Castren,2005)
In most cases, one particular medication or combination of medications can provide significant change, although, in some cases, the condition does not respond well. Treatment-resistant depression warrants a full assessment, which may lead to the introduction of psychotherapy, a focus on lifestyle change, an increase of medication, or a change in medication.
In emergencies, hospitalization is an intervention employed to keep at-risk individuals safe until they cease to be a danger to themselves or others. An alternative treatment program is partial hospitalization, in which the patient sleeps at home but spends most of the day in a psychiatric hospital setting. This intensive treatment usually involves group therapy, individual therapy, medication management, and often in the case of children and adolescents, academics.
Medication
Medication that relieves the symptoms of depression has been available for several decades. Typical first-line therapy for depression is the use of a selective serotonin reuptake inhibitor, such as citalopram (Celexa), fluoxetine (Prozac), paroxetine (Paxil), and sertraline (Zoloft). Under some circumstances, medication and psychotherapy may be more effective than either treatment separately(Thase,1999). Selective serotonin reuptake inhibitors (SSRIs)
Selective serotonin reuptake inhibitors (SSRIs) are a family of antidepressants considered to be the current standard of drug treatment. It is thought that one cause of depression is an inadequate amount of serotonin, a chemical used in the brain to transmit signals between neurons. SSRIs are said to work by preventing the reuptake of serotonin by the presynaptic nerve, thus maintaining higher levels of 5-HT in the synapse. Recently, however, work by two researchers has called into question the link between serotonin deficiency and symptoms of depression, noting that the efficacy of SSRIs as treatment does not in itself prove the link.(Lacasse and Leo,2005). Recent research indicates that these drugs may interact with transcription factors known as "clock genes", which may be important for the addictive properties of drugs of abuse and possibly in obesity.(Yuferov et al., 2005)
Recent randomized controlled trials in Archives of General Psychiatry showed that up to one-third of effects of SSRI Treatment can be seen in first week. Early effects also shown to have secondary effect of reducing absolute reduction in HDRS score by 50 percent. Even more recent studies, published by the Archives of General Psychiatry note that 25% of so-called clinical depression does not meet a disease criteria and should be considered to be ordinary sadness and adjustment to the difficulties in life.
This family of drugs includes fluoxetine (Prozac), paroxetine (Paxil), escitalopram (Lexapro), citalopram (Celexa), and sertraline (Zoloft). These antidepressants typically have fewer adverse side effects than the tricyclics or the MAOIs, although such effects as drowsiness, dry mouth, nervousness, anxiety, insomnia, decreased appetite, and decreased ability to function sexually may occur. Some side effects may decrease as a person adjusts to the drug, but other side effects may be persistent. Though safer than first generation antidepressants, SSRI's may not work as often, suggesting the role of norepinephrine. However, it should be noted that all psycho-active medications extend the reaction time, thus increasing the likelihood of falls and road crashes.
Psychotherapy
In psychotherapy, or counseling, one receives assistance in understanding and resolving habits or problems that may be contributing to or the cause of the depression. This may be done individually or with a group and is conducted by mental health professionals such as psychiatrists, psychologists, clinical social workers, or psychiatric nurses.
Effective psychotherapy may result in different habitual thinking and action which leads to a lower relapse rate than antidepressant drugs alone. Medication, however, may yield quicker results and be strongly indicated in a crisis. Medication and psychotherapy are generally complementary, and both may be used at the same time.
Transcranial magnetic stimulation
Repetitive transcranial magnetic stimulation (rTMS) is under study as a possible treatment for depression. Initially designed as a tool for physiological studies of the brain, this technique shows promise as a means of alleviating depression. In this therapy, a powerful magnetic field is used to stimulate the left prefrontal cortex, an area of the brain that typically shows abnormal activity in depressed people.
Recent work in Poland suggested that weak, variable magnetic fields may offer relief from depression in those who have not responded to medication. However, some of the existing work has been questioned, with claims that the effect is not as significant once environmental conditions are controlled.
Vagus nerve stimulation
Vagus nerve stimulation therapy is a treatment used since 1997 to control seizures in epileptic patients and has recently been approved for treating resistant cases of treatment-resistant depression (TRD). The VNS Therapy device is implanted in a patient's chest with wires that connect it to the vagus nerve, which it stimulates to reach a region of the brain associated with moods. The device delivers controlled electrical currents to the vagus nerve at regular intervals.
Electroconvulsive therapy
Electroconvulsive therapy (ECT), also known as electroshock or electroshock treatment, uses short bursts of a controlled current of electricity (typically fixed at 0.9 ampere) into the brain to induce a brief, artificial seizure while the patient is under general anesthesia.
In contrast to direct electroshock of years ago, most countries now allow ECT to be administered only under anaesthesia. In a typical regimen of treatment, a patient receives three treatments per week over three or four weeks. Repeat sessions may be needed. Short-term memory loss, disorientation, and headache are very common side effects. Detailed neuropsychological testing in clinical studies has not been able to prove permanent effects on memory. ECT offers the benefit of a very fast response; however, this response has been shown not to last unless maintenance electroshock or maintenance medication is used. Whereas antidepressants usually take around a month to take effect, the results of ECT have been shown to be much faster. For this reason, it is the treatment of choice in emergencies (e.g., in catatonic depression in which the patient has ceased oral intake of fluid or nutrients).
There remains much controversy over electroshock. Advocacy groups and scientific critics, such as Dr Peter Breggin, call for restrictions on its use or complete abolishment. Like all forms of psychiatric treatment, electroshock can be given without a patient's consent, but this is subject to legal conditions dependent on the jurisdiction. In Oregon patient consent is necessary by statute.
Light therapy
Bright light (both sunlight and artificial light) is shown to be effective in seasonal affective disorder, and sometimes may be effective in other types of depression, especially atypical depression or depression with "seasonal phenotype" (overeating, oversleeping, weight gain, apathy).
Exercise
It is widely believed that physical activity and exercise help depressed patients and promote quicker and better relief from depression. They are also thought to help antidepressants and psychotherapy work better and faster. It can be difficult to find the motivation to exercise if the depression is severe, but sufferers should be encouraged to take part in some form of regularly scheduled physical activity. A workout need not be strenuous; many find walking, for example, to be of great help. Exercise produces higher levels of chemicals in the brain, notably dopamine, serotonin, and norepinephrine. In general this leads to improvements in mood, which is effective in countering depression.
Meditation
Meditation is increasingly seen as a useful treatment for some cases of depression. The current professional opinion on meditation is that it represents at least a complementary method of treating depression, a view that has been endorsed by the Mayo Clinic. Since the late 1990s, much research has been carried out to determine how meditation affects the brain (see the main article on meditation). Although the effects on the mind are complex, they are often quite positive, encouraging a calm, reflective, and rational state of mind that can be of great help against depression.
Deep brain stimulation
Though still experimental, a new form of treatment called deep brain stimulation offers some hope in the relief of treatment resistant clinical depression. Published in the journal Neuron (2005), Helen Mayberg described the implanting of electrodes in a region of the brain known as Area 25 The electrodes act in an inhibitory fashion, on an otherwise overactive region of the brain. Further research is required before it becomes available as a method of treatment, but it offers hope for those suffering from treatment resistant depression.
Dr Smita Pandey Bhat, Cinical Psychologist