Theories have been suggested towards the psychotic like traits in animals that have been subjected to psychoactive drugs.

The proposed theories were accompanied by research experiments to evaluate the effects of psychoactive drug testing in animals. Psycho active drugs refers to drugs that have a significant effect on the behavioral characteristics of animals; both human and non human organisms. The alterations in behavioral traits of animals due to psychoactive drugs are primarily attributed to the changes in the brain functions or inhibition of certain brain components in animals which ultimately translates to changes in moods, behavior, and consciousness of the animals. Psychoactive drugs are known to bring subjective changes with regard to consciousness, for instance alertness that is observed in animals that have been subjected to psychoactive drugs such as caffeine and cocaine.

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Apart from psychoactive medications, there are many other substances that are responsible for psychotropic behaviors in animals. Such drug substances include alcohol, cocaine, marijuana, opium, caffeine, heroine and nicotine that are well known to have profound effects on animals such as cats, spiders, rats and other animals (Stahl 159). Psychoactive drugs can be classified primarily into four categories: antipsychotics which are used for treatment of states of agitation; antidepressants which are used for depression treatment; mood stabilizers; anxiolytics which are used to treat anxiety states; physiostimulants which are used to increase the physical performance of the animal’s body; Nootropics which assists in the cognitive functions of the human brain (Spiegel & Hossein 135).

This research paper attempts to explain the theories, hypotheses and effects of psychoactive drugs on animal drug testing.

Theory oriented issues on psychoactive drugs

Research in the field of psychopharmacology have inferred the probability of utilizing psychoactive drugs using experimental approach for theory oriented objectives: a central research strategy for the physiological psychology is through the administration of psychotic drugs to human and non human organisms (Stahl 145). Theoretical approach is different from the other classical approaches to psychopharmacology such as lesions which attempt to evaluate the effects of different doses (in terms of quantifiability and reversibility) to evaluate the effects of psychoactive drugs on animals. The only feasible method to study the effect of psychoactive substances in animals, for example rats and mice is through experimental administration of the psychoactive drugs into the animals and monitoring behavioral and performance traits (Spiegel & Hossein 202).

Questions concerning the relationship between behavioral characteristics and the animal brain may be evaluated through establishing the relationship between the dopaminergic functions, and specific aspects that are vital in determining attention and motivation. Theory oriented approach towards pharmacology emphasized on the relationship between changes in animal behavioral traits and drug actions. It was shown that test subjects with high levels agitation had responded differently to psychoactive drugs compared to those with less anxiety. This difference in response is asserted by the theory of activation; due to the different levels of arousals which is subjective to the levels of and agitation in the animals under test (Spiegel & Hossein 205).

Hypotheses in psychopharmacology

The hypothetical approach towards psychopharmacology was due to the need to have analytical explanations of the physiological and psychological concepts that are related to the effects of psychoactive drugs on animals. Early speculations suggested disturbance on the in the brain in terms of biological perspectives, but analytical approaches that were required to approve or disapprove the suggestions were not obtainable; therefore, the rise of hypothetical approaches towards psychopharmacology. Some of the suggested hypotheses are outlined below (Spiegel & Hossein 150).

The serotonin hypothesis of Schizophrenia

This hypothesis was first postulated by Woolley and Shaw; two American biochemists, during 1954. The hypothesis stated that Schizophrenia like traits that are exhibited in animals is primarily due to disturbances during the setoninenergic neurotransmission in the animal brain (Stahl & Lerer 160). Schizophrenic traits in animals include rapid changes in the animal personality and moods of the animal test subject. The hypothesis has a number of supporting facts which include: the psychotropic actions of the LSD (lysergic acid diethylamide), which has the capability to trigger alterations in perceptions, thoughts and also feelings in the animal’s brain. The LSD also has the capabilities to block the activity of serotonin which was proved later in various tests (Stahl & Lerer 162).

Woolley and Shaw were of the view that serotonin is present in the animal brain and functions as a neurotransmitter, it was therefore speculated the psychotropic effects in animals associated with LSD’s ability to resist the effects of the serotonin on the animal brain; therefore it was reached that disturbances in the serotoninergic neurotransmission is primarily responsible for psychotropic disorders in the animal test subjects (Stahl & Lerer 162). Despite of the enough scientific evidence and appeal, the serotonin hypothesis of Schizophrenia was soon refuted due to its conflict psychopathological and pharmacology research finding that revealed that the psychotic symptoms in animal test subjects that associated with LSD differ from the typical symptoms that are associated schizophrenia. Although this hypothesis was refuted fast, it was important in two aspects: it facilitated the proposition of serotonin assay methods and provided proof that serotonin is not present in the brain, it also served as a prototype for the other forthcoming hypotheses (Stahl & Lerer 163).

The dopamine Hypotheses of Schizophrenia

The drawback of the serotonin hypothesis of schizophrenia was that it lacked direct correlation with the properties associated with psychoactive drugs.

The context of dopamine hypothesis is different because all known psychoactive substances have an inhibitory effect in the dopaminergic neurons in the animal brain, although they differ with respect to pharmacological side effects on humans. The hypothesis assumes that the antipsychotic nature of chlorpromazine and other similar neuropletics is significantly determined by their cataleptic potential; their capability to induce catalepsy in animals. This hypothesis lost its credibility during the discovery that thiorodazine, which is a similar neuropletic to chlorpromazine had little effects (Stahl & Lerer 155).

Despite the critic that followed the hypothesis, there were a number of adjustments to the dopamine hypothesis on schizophrenia. The argument of the hypothesis that neuropletics act through blocking of the post synaptic dopamine receptors is still consistent with majority of pharmacological research observations (Stahl & Lerer 155).

The catecholamine hypothesis of Depression

The hypothesis was first suggested during 1965 by J.

Schildkraut. The hypothesis states that majority of depression like behavior in animals are due to part or total deficiency of catecholamine, which functions at the receptor sites in the animal brain. The hypothesis was consistent with the clinical and pharmacological research findings (Schatzberg & Nemerof 199). The catecholamine hypothesis can be attributed for the bringing together of several pharmacological research findings but contradicted many clinical observations, especially the delay on the onset of action of the anti depressant drugs on animal test subjects. The same applies to the serotonin hypothesis (Stahl & Lerer 124).

The serotonin hypothesis of depression

The serotonin hypothesis of depression states that majority of depression traits in animals are due to absolute deficiency of serotonin in some of the parts of the brain.

A number of arguments have been suggested to support the hypothesis (Schatzberg & Nemerof 200). There is also a number of pharmacological finding that support the serotonin and catecholamine hypothesis of depression. Depressions like traits in animals are not a single disorder; there are depressions that related to the serotonin deficiency and on a similar account catecholamine deficiency (Schatzberg & Nemerof 205).

Effects of psychoactive drugs

The effects of psychoactive drugs on animals can be viewed from the following perspectives: drug oriented, which is primarily defined by the compound composition of the psychoactive drug; methodology oriented, which is defined by the sensitivity of the animal under the drug test to the psychoactive drugs; theory oriented, which described by analysis of the brain behavior of the animal under test due to the psychoactive drug use; practical oriented which describes the effects of psychoactive drugs on everyday activities (Schatzberg & Nemerof 205). There are a number of effects associated with psychoactive drug uses which are outlined below according the results of psychoactive drug testing on animals. Psychoactive drugs usually have strong effects on animals. Some of the psychoactive drugs that significantly affect animals in different ways include: caffeine, LSD, marijuana and many more. Majority of Pharmacological research concerning the effects of psychoactive drugs reported that at small concentrations, psychoactive drugs have an effect on the feeding behaviors of insects and molluscs.

At high concentration, it is reported that psychoactive drugs could cause death on the test subjects (Schatzberg & Nemerof 206). Psychotic drugs usually have notable effects on the animal test subjects; these effects can be described principally as being subjective effects. In addition, there are effects that may be noticed by the observer, such as performance deterioration. Such effects are generally termed behavioral effects. A study on spiders revealed that spiders constructed more disordered webs after being subjected to psychoactive drugs than when they have not been subjected to psychoactive drugs (Schatzberg & Nemerof 208).

A research by a German pharmacologist, P. N Witt on the effects of psychotic drugs on spiders revealed that the shape and size of the webs constructed by the spiders varied significantly when the spiders were subjected to the psychotic drugs. At smaller amounts of caffeine, the webs were a little regular with uniform radii. At higher doses of about 100 microgram per spider, the webs were much more disoriented and irregular (Schatzberg & Nemerof 205). This implies that psychoactive drugs are responsible performance deterioration in animals such as spiders. It is widely believed that other plants developed psychoactive substances in their leaves in order to serve as a protection mechanism against the harmful animals such as spiders.

Another category of psychoactive drug use effect is the neurophysiological effects which primarily affect the functionality of the animal brain. This is primarily responsible for observations of hyperactivity and tremor in animal test subjects. Various parameters are used to measure the extent of the effects of the psychotic drugs on animal test subjects (Schatzberg & Nemerof 197).

During 1984, a pharmacologist named Nathanson carried our research on the effects of psycho stimulants on arthropods and molluscs. Cats that were subjected to higher doses of caffeine revealed higher levels of hyperactivity; as evidenced through licking of their cheeks, rolling over the ground and to some extent sexual arousal (Stahl 156). Another effect that is associated with the testing of psychoactive drugs on animals is the alterations in the behavioral traits of the animal test subject. Psychotic drugs have reported increased effects on the alterations of animals’ behavior. This is due to the effects of the drugs on the way the brain functions. Any change in the dopamine levels in the animal test subject’s brain is sufficient enough to induce behavioral change in the test subjects (Stahl 198). Behavioral pharmacology research studies have indicated that rats and mice that have been subjected to small doses of cocaine have higher response rates than ordinary rats and mice.


Psychoactive drugs use is bound to cause harmful effects on the animal test subjects. These psychological effects are primarily attributed due to alterations in the brain functionality as the above theories and hypotheses suggests; this explicitly explains the hyperactivity and tremor behavior in animals that have been subjected to psychoactive drugs. Some of the common physiological effects that are associated with the use of psychoactive drugs include mood alterations, consciousness and drowsiness, which are primarily due to impairing the functionality of the brain. All the hypotheses are drawn from one perspective; a given substance is antagonistic towards the brain activity and that is the underlying principle that explains the nature of psychoactive drugs (Spiegel & Hossein 205).

Works Cited

Schatzberg, Alan F. and Nemeroff B.

Charles. Essentials of clinical psychopharmacology. Washington, D.C: American Psychiatric Pub, 2006. Print. Spiegel, Rene and Hossein Fatemi. Psychopharmacology: an introduction.

Chichester: John Wiley and Sons, 2003. Print. Stahl, Stephen.

Stahl’s essential psychopharmacology: neuroscientific basis and practical applications. New York: Cambridge University Press, 2008. Print. Stahl, Stephen and Lerer ,Bernard. Evidence-based psychopharmacology. New York: Cambridge University Press, 2008.



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