Depression
In the fields of psychology and psychiatry, depression refers to a state of low mood and aversion to activity. While most often described as a disease or dysfunction, there are also strong arguments for seeing depression as an adaptive defense mechanism.
The Diagnostic and Statistical Manual of Mental Disorders defines a depressed person as experiencing feelings of sadness, helplessness and hopelessness. In traditional colloquy, "depressed" is often synonymous with "sad", but both clinical depression and non-clinical depression can also refer to a conglomeration of more than one feeling.
Biology
Biological influences of depression are varied, but may relate to malnutrition, heredity, hormones, seasons, stress, illness, drug or alcohol use, neurotransmitter malfunction, long-term exposure to dampness and mold, back injury, and to aerosol exposure. There are also correlations between long term sleep difficulties and depression. Up to 90% of patients with depression are found to have sleep difficulties.
Depression as a defense mechanism
A number of authors have suggested that depression is an evolutionary adaptation. A low or depressed mood can increase an individual's ability to cope with situations in which the effort to pursue a major goal could result in danger, loss, or wasted effort. In such situations, low motivation may give an advantage by inhibiting certain actions. This theory helps to explain why depression is so prevalent, and why it so often strikes people during their peak reproductive years. These characteristics would be difficult to understand if depression were a dysfunction, as many psychiatrists assume.
Depression is a predictable response to certain types of life occurrences, such as loss of status, divorce, or death of a child or spouse. These are events that signal a loss of reproductive ability or potential, or that did so in humans' ancestral environment. Depression can be seen as an adaptive response, in the sense that it causes an individual to turn away from the earlier (and reproductively unsuccessful) modes of behavior.
A depressed mood is common during illnesses, such as influenza. It has been argued that this is an evolved mechanism that assists the individual in recovering by limiting his/her physical activity.[6] The occurrence of low-level depression during the winter months, or seasonal affective disorder, may have been adaptive in the past, by limiting physical activity at times when food was scarce. It is argued that humans have retained the instinct to experience low mood during the winter months, even if the availability of food is no longer determined by the weather.
An alternative theory posits that depression is a plea for help. However this view is not widely credited by evolutionary biologists: depression is observed in other species that are not social, and depression in humans is often actively hidden from others; even when it is apparent, it often fails to elicit a positive response.
Milder depression has been associated with what has been called depressive realism, or the "sadder-but-wiser" effect, a view of the world that is relatively undistorted by positive biases.
Treatment for depression
Psychotherapy
There are a number of different psychotherapies for depression, which may be provided to individuals or groups. Psychotherapy can be delivered by a variety of mental health professionals, including psychotherapists, psychiatrists, psychologists, clinical social workers, counselors, and psychiatric nurses. With more complex and chronic forms of depression the most effective treatment is often considered to be a combination of medication and psychotherapy. Psychotherapy is the treatment of choice in people under 18; medication is offered only in conjunction with the former and generally not as a first line agent.
The most studied form of psychotherapy for depression is cognitive behavioral therapy (CBT), thought to work by teaching clients to learn a set of cognitive and behavioral skills, which they can employ on their own. Earlier research suggested that cognitive-behavioral therapy was not as effective as antidepressant medication in the treatment of depression; however, more recent research suggests that it can perform as well as antidepressants in treating patients with moderate to severe depression.
For the treatment of adolescent depression, CBT performed no better than placebo, and significantly worse than the antidepressant fluoxetine. Combining fluoxetine with CBT appeared to bring no additional benefit or, at the most, only marginal benefit.
A review of four studies on the effectiveness of mindfulness-based cognitive therapy (MBCT), a recently developed class-based program designed to prevent relapse, suggests that MBCT may have an additive effect when provided with the usual care in patients who have had three or more depressive episodes, although the usual care did not include antidepressant treatment or any psychotherapy, and the improvement observed may have reflected non-specific or placebo effects.
Interpersonal psychotherapy focuses on the social and interpersonal triggers that may cause depression. There is evidence that it is an effective treatment for depression. Here, the therapy takes a structured course with a set number of weekly sessions (often 12) as in the case of CBT, however the focus is on relationships with others. Therapy can be used to help a person develop or improve interpersonal skills in order to allow him or her to communicate more effectively and reduce stress.
Psychoanalysis, a school of thought founded by Sigmund Freud that emphasizes the resolution of unconscious mental conflicts, is used by its practitioners to treat clients presenting with major depression. A more widely practiced, eclectic technique, called psychodynamic psychotherapy, is loosely based on psychoanalysis and has an additional social and interpersonal focus. In a meta-analysis of three controlled trials, psychodynamic psychotherapy was found to be as effective as medication for mild to moderate depression.
Medication
To find the most effective pharmaceutical treatment, the dosages of medications must often be adjusted, different combinations of antidepressants tried, or antidepressant changed. Response rates to the first agent administered may be as low as 50%. It may take anywhere from three to eight weeks after the start of medication before its therapeutic effects can be fully discovered. Patients are generally advised not to stop taking an antidepressant suddenly and to continue its use for at least four months to prevent the chance of recurrence. People with chronic depression need to take the medication for the rest of their lives.
Selective serotonin reuptake inhibitors (SSRIs), such as sertraline (Zoloft), escitalopram (Lexapro), fluoxetine (Prozac), paroxetine, and citalopram are the primary medications considered, due to their relatively mild side effects and broad effect on the symptoms of depression and anxiety. Those who do not respond to the first SSRI tried can be switched to another; such a switch results in improvement in almost 50% of cases. Another popular option is to switch to the atypical antidepressant bupropion (Wellbutrin) or to add bupropion to the existing therapy; this strategy is possibly more effective. It is not uncommon for SSRIs to cause or worsen insomnia; the sedating antidepressant mirtazapine (Zispin, Remeron) can be used in such cases. Venlafaxine (Effexor) may be moderately more effective than SSRIs; however, it is not recommended as a first-line treatment because of the higher rate of side effects, and its use is specifically discouraged in children and adolescents. Fluoxetine is the only antidepressant recommended for people under the age of 18.
Tricyclic antidepressants have more side effects than SSRIs and are usually reserved for the treatment of inpatients, for whom the tricyclic antidepressant amitriptyline, in particular, appears to be more effective. A different class of antidepressants, the monoamine oxidase inhibitors, have historically been plagued by questionable efficacy and life-threatening adverse effects. They are still used only rarely, although newer agents of this class (RIMA), with a better side effect profile, have been developed.
There are numerous alternative treatments for depression, whether medications or other kinds of intervention.
