![Forced-swimming test](https://upload.wikimedia.org/wikipedia/commons/0/02/Forced-swimming_test.jpg)
The behavioural despair test (or Porsolt forced swimming test) is a test, centered on a rodent's response to the threat of drowning, whose result has been interpreted as measuring susceptibility to negative mood. It is commonly used to measure the effectiveness of
antidepressants
Antidepressants are a class of medication used to treat major depressive disorder, anxiety disorders, chronic pain conditions, and to help manage addictions. Common side-effects of antidepressants include dry mouth, weight gain, dizziness, hea ...
,
although significant criticisms of its interpretation have been made.
Method
Animals are subjected to two trials during which they are forced to swim in an acrylic glass cylinder filled with water, and from which they cannot escape. The first trial lasts 15 minutes. Then, after 24-hours, a second trial is performed that lasts 5 minutes. The time that the test animal spends in the second trial without making any movements beyond those required to keep its head above water
is measured. This immobility time is decreased by various types of antidepressants and also by
electroconvulsive shock
Electroconvulsive therapy (ECT) is a psychiatric treatment where a generalized seizure (without muscular convulsions) is electrically induced to manage refractory mental disorders.Rudorfer, MV, Henry, ME, Sackeim, HA (2003)"Electroconvulsive th ...
.
Another common variant of this behavioural test specifically used for mice is conducted only for one trial and lasts six minutes. Modern implementations of the test score swimming and climbing behaviours separately, because swimming behaviour has been shown to be increased by
selective serotonin reuptake inhibitor
Selective serotonin reuptake inhibitors (SSRIs) are a class of drugs that are typically used as antidepressants in the treatment of major depressive disorder, anxiety disorders, and other psychological conditions.
SSRIs increase the extracellul ...
s, while climbing behaviour is increased by selective
norepinephrine reuptake inhibitor
A norepinephrine reuptake inhibitor (NRI, NERI) or noradrenaline reuptake inhibitor or adrenergic reuptake inhibitor (ARI), is a type of drug that acts as a reuptake inhibitor for the neurotransmitters norepinephrine (noradrenaline) and epin ...
s such as
desipramine
Desipramine, sold under the brand name Norpramin among others, is a tricyclic antidepressant (TCA) used in the treatment of depression. It acts as a relatively selective norepinephrine reuptake inhibitor, though it does also have other activiti ...
and
maprotiline
Maprotiline, sold under the brand name Ludiomil among others, is a tetracyclic antidepressant (TeCA) that is used in the treatment of depression. It may alternatively be classified as a tricyclic antidepressant (TCA), specifically a secondary am ...
.
Controversy in interpretation
Classically, immobility in the second test has been interpreted as a behavioural correlate of negative mood, representing a kind of hopelessness in the animal. Rodents given antidepressants swim harder and longer than controls (which forms the basis for claims of the test's validity). However, there is some debate between scientists whether increased immobility instead demonstrates
learning or
habituation
Habituation is a form of non-associative learning in which an innate (non-reinforced) response to a stimulus decreases after repeated or prolonged presentations of that stimulus. Responses that habituate include those that involve the intact org ...
, and would therefore be a positive behavioural
adaptation:
the animal is less fearful because it is now familiar with the environment of the test. This interpretation is supported by the fact that even rats who are first put into a container from which they can escape (and therefore do not experience despair) show reduced mobility in the second test.
Some pharmacological compounds that influence motor movement, like stimulants and sedatives, may cause animals to swim for different amounts of time that are unrelated to the antidepressant properties of the compound. Researchers need to assess locomotor activity in the animal's homecage or by a locomotor test. If locomotion is altered compared to controls then other animal antidepressant models should be used.
The term "behavioural despair test" bears an
anthropomorphic connotation and is a somewhat subjective description as it is uncertain whether the test reliably gauges mood or despair. Strictly speaking, the descriptive term "forced swimming test" is preferred by researchers.
The use of forced swimming tests is criticised by
animal rights groups
This list of animal rights groups consists of groups in the animal rights movement. Such animal rights groups work towards their ideals, which include the viewpoint that animals should have equivalent rights to humans, such as not being "used" i ...
, notably
PETA.
[{{Cite news, url=http://www.peta.org/issues/animals-used-for-experimentation/animals-laboratories/mice-rats-laboratories/, title=Mice and Rats in Laboratories, newspaper=PETA, language=en-US, access-date=2016-11-02]
See also
*
Animal models of depression
Animal models of depression are research tools used to investigate depression and action of antidepressants as a simulation to investigate the symptomatology and pathophysiology of depressive illness or used to screen novel antidepressants.
In ...
*
Learned helplessness
Learned helplessness is the behavior exhibited by a subject after enduring repeated aversive stimuli beyond their control. It was initially thought to be caused by the subject's acceptance of their powerlessness, by way of their discontinuing atte ...
*
Open field (animal test)
Developed by Calvin S. Hall, the open field test is an experimental test used to assay general locomotor activity levels, anxiety, and willingness to explore in animals (usually rodents) in scientific research. However, the extent to which behavio ...
*
Tail suspension test
The tail suspension test (TST) is an experimental method used in scientific research to measure stress in rodents. It is based on the observation that if a mouse is subjected to short term inescapable stress then the mouse will become immobile ...
References
Animal testing techniques
Psychology experiments