Motivation and emotion/Book/2020/Phencyclidine and emotion

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Phencyclidine and emotion:
What are the emotional effects of phencyclidine?

Overview[edit | edit source]

Figure 1. Chemical Structure of Phencyclidine

The purpose of this book chapter is to understand the emotional effects Phencyclidine has on individuals. Research into Phencyclidine and the the effects on the human body has increased over the last few years.

Focus questions

  • What is Phencyclidine?
  • What is Emotion?
  • What are the short and long term emotional effects of Phencyclidine?
  • How can we apply psychological theory to Phencyclidine use?

What is Phencyclidine?[edit | edit source]

Figure 3. Four components of Emotion

Phencyclidine (1- phenylcyclohexyl piperidine), a hallucinogenic drug, that is believed to affect the central nervous system in multiple ways, the drug inhibits the reuptake of nor-epinephrine, Serotonin and dopamine and glutamate by blocking the non-competitive N-methyl-d-aspartate (NMDA) receptor (Domino & Luby, 2012)[grammar?]. Phencyclidine is often referred to as "Angel Dust" or "PCP". Phencyclidine is now banned world wide and considered a schedule II substance. Phencyclidine intoxication can vary greatly, this depends on the amount of the drug is consumed, the effects of the drug can last anywhere between 4-48 hours[grammar?]. Lower doses of intoxication have been seen to cause the individual a feeling of relaxation and to become emotionally numb (Kusljic & Van Den Buuse 2012). Phencyclidine has also been linked to violent behavior and drug induced psychosis (T & A, 2020).

What is emotion?[edit | edit source]

Over the years, many health professionals to tried to come to a consensus on "What is Emotion?" although there is yet to be a scientific consensus on the definition, it has been agreed that Emotion is state of feeling, usually caused by an event, that results in psychology and physiological changes within the body that influences the individual's thought and behaviour (Anderson & Adolphs, 2014). See Figure 3.

History[edit | edit source]

[Provide more detail]

Early Use[edit | edit source]

Phencyclidine was first introduced in 1926, Victor Maddox, a chemist from Michigan, US was originally investigating the synthetic analgesic agents of the drug, it was through this investigation that its anesthetic properties were discovered ("Phencyclidine", 2020).

1950s[edit | edit source]

Phencyclidine was approved for use as a anesthetic under the brand name Sernyl, Originally for investigation purposes as an anesthetic (T & A, 2020) .

1960s[edit | edit source]

Due to the long half-life of the drug[how long?] and the adverse side effects patients were experiencing such as mania, disorientation, delirium and hallucinations it was removed from the market. It became limited to only veterinary use. At this time Phencyclidine entered the recreation drug scene (Kusljic & Van Den Buuse 2012).

1970s[edit | edit source]

The complete banning of Phencyclidine for human consumption and veterinary use (T & A, 2020).

1980 to present[edit | edit source]

Today, Phencyclidine has been classified as a Schedule II substance, drugs that have been placed under this schedule, have a high warning of of abuse and that the use may become both psychologically or physiologically dependent on them[grammar?].

Quiz 1[edit | edit source]

Choose the correct answer and click "Submit".

What year was Phencyclidine discovered?


Emotional affects and the brain[edit | edit source]

Figure 4. Neurotransmitters affected by Phencyclidine

According to a number of sources[factual?], the technical mechanisms of Phencyclidine is complicated and still not fully understood, although it is known that Phencyclidine affects multiple neurotransmitters in the brain. There has been limited research trials of Phencyclidine since being banned, and these have been limited to mice and rats. Phencyclidine affects the neurotransmitter N-methyl-D-aspirate (NDMA), this is an excitatory neurotransmitter, this inhibits the functioning of neurotransmitters, Glutamate, serotonin and dopamine[grammar?]. It specifically effects[grammar?] the D2 dopamine receptor. This particular dopamine receptor is often studied with individuals that[grammar?] have schizophrenia. More evidence has emerged during the studies of schizophrenia of a malfunction in the N-methyl-D-aspartate (NMDA)-glutamate transmission system in individuals that have a schizophrenia diagnosis (Olney et al., 1999). This finding has been discussed as a possible link between,[grammar?] Phencyclidine use and the schizophrenia-like psychosis which includes both positive and negative symptoms along with cognitive impairment (Javitt and Zukin, 1991; Krystal et al., 1994; Luby et al., 1959; Malhotra et al., 1997). Phencyclidine has also also been seen to affect endorphins and enkephalins, [grammar?] these particular neurotransmitters are directly involved in the suppression of pain, this accounts for the anaesthetic effects of the drug. The NMDA Receptor has been linked to play an[grammar?] central role in the mechanisms of emotionality, learning and memory.

Emotion Process Networks[edit | edit source]

Figure 5. The limbic System

The Hippocampus, a major component of the brain[grammar?]. Humans have two hippocampus, one on each side of the brain. The hippocampus is part of the Limbic System, and plays an important role in memory consolidation for both long and short term memory, and learning. The hippocampus is located in the Temporal lobe (Dhikav & Anand, 2012). phencyclidine inhibits the processing of emotion, learning and memory in the hippocampus, it can create both positive and negative responses to external stimuli and potentially psychosis. These findings are important, as if the Hippocampus becomes unbalanced, there is a risk that psychological disorders may develop, such as anxiety disorders (Barkus et al., 2010). See Figure 5[grammar?].

Quiz 2[edit | edit source]

Choose the correct answer and click "Submit".

What receptor doesn't Phencyclidine inhibit?


Psychological theories of emotion[edit | edit source]

Both Biological and Cognitive perspective's on Emotion can help explain how Phencyclidine affects emotion.

James-Lange theory[edit | edit source]

Figure 6. James-Lange Theory of Emotion

This theory, established in late 1800's[grammar?] by psychologist William James and Carl Lange, who independently shared their theories of emotion approximately the same time, later combined their theories which is now presented as the James-Lange Theory of Emotion. From this perspective, emotion can only be equivalent to the physiological arousal that is caused by external events. For an individual to feel emotion, he/she must first experience the bodily responses such as increased heart rate or sweating. Once the physiological response is received then the individual will feel the emotion related to the physiological response.

This may be consistent with the emotional effects of Phencyclidine as it distorts an individuals[grammar?] perception of self, reality and the environment surrounding them (Snigdha et al., 2010). Phencyclidine is a Hallucinogenic drug, which also works in ways similar to a stimulant, this causes a physiological response within the body, which causes a heighten feeling of emotion. This perspective fits with the effects Phencyclidine has on the body, brain and consequently the feeling of emotion (Davis, 1982). See Figure 6[grammar?].

Lazarus cognitive-mediational theory[edit | edit source]

This theory, established in 1991 was propose[grammar?] by Richard Lazarus. The theory proposes that emotional states are elicited by appraisals (our evaluations, interpretations and explanations) of events or situations. An individual's emotion's[grammar?] are determined by by our appraisals of stimuli (internal or external). The appraisal is the mediator between the stimulus and the emotional response, and is often unconscious (Roseman et al., 2001). Phencyclidine may have an effect on how individuals evaluate stimuli specifically intensification of feelings and bodily responses[grammar?]. Phencyclidine is known to cause feelings of detachment and dissociation, [grammar?]If the experience is evaluated as negative, a negative emotional experience could occur, which could be extremely dangerous not only for users but for those around them (Koseki T et al., 2010). See table 1.

Table 1.

Illustration of the process of Lazarus' cognitive-mediational theory
Stimulus Appraisal Physiological Response / Emotional Response

Facial feedback hypothesis[edit | edit source]

The facial feedback hypothesis states that emotions results from facial expressions. It is stated[factual?] that the contraction of facial muscles may communicate what the person feels to others but also to the individual them self. Facial expressions are said to have direct influence on emotional states . This hypothesis originated with Charles Darwin. A second origin of the facial feedback hypothesis originated with William James (Davis, Senghas & Ochsner, 2009). Phencyclidine use usually triggers facial grimacing, this facial expression usually suggests disgust or pain[factual?]. It can be seen as an individual wrinkling his/her nose, squeezing his/her eyes and squeezing of the lips. These uncontrollable facial movements may influence negative emotions and an overall negative experience being experienced by the individual, this supports the facial feedback hypothesis (Petersen & Stillman, 1978). See table 2.

Table 2.

Illustration of the process of Facial Feedback Hypothesis
Event Facial Expression Emotional Response

Quiz 3[edit | edit source]

Choose the correct answer and click "Submit".

What theory states emotions result from facial expressions?

James-Lange theory
Lazarus cognitive-mediational theory
Facial feedback hypothesis

Short term and long term effects[edit | edit source]

There are many effects associated with Phencyclidine use, both short and long term. There has been little studies[grammar?] conducted on Phencyclidine Intoxication and human consumption with most case studies being conducted on Rats and Mice.

Figure 7. A visual diagram of the effects of Phencyclidine

Short term effects[edit | edit source]

Phencyclidine intoxication can vary, this all depends on the amount of the drug the individual consumes[grammar?]. The effects of the drug can last between 4 and 48 hours[factual?]. In the lower doses of the drug (usually between 2-5 mg), the individual may feel relaxed, euphoric, pain-free or emotionally numb. The individual may appear drunk, slur their speech, and get dizzy. In higher levels of consumption of the drug, the individual may stare blankly, shiver or twitch, repeat movements such has tapping foot repetitively on the ground or rocking their body back and forth. Large doses also lead to hallucinations (T & A, 2020). See figure 7[grammar?]. Phencyclidine induced behaviors can lead to aggressive and violent behaviours (Kusljic & Van Den Buuse 2012) as well as distorted body image, depersonalisation, senses of euphoria and possibly total disorientation when taken in higher doses (Tekulve, Tormoehlen & Walsh 2017). See table 3[grammar?].

Table 3.

(T & A, 2020) found Neuro psychiatric and clinical effects of PCP at different doses

Estimated ingested amount Clinical effects
2–5 mg (Stage I) Unpredictable, drunk, euphoric, disoriented, combativeness, rage obscenity.
Alternating periods of lethargy and fearful agitation: waxing and waning.
Decreased but intact pain perception, midpoint pupils, nystagmus, ataxia differentiates PCP from stimulants.
5–25 mg (Stage II) Stupor, mild coma, intact response to deep pain, muscle contractions, bizarre postures.
More than 25 mg (Stage III) Comatose with no response to deep pain, hyperthermia, convulsions, death.

Long term effects[edit | edit source]

While there has been limited research regarding the long term effects of Phencyclidine abuse, it is known that the longer the individual uses the drug, the more likely they are to experience long term side effects from it[factual?]. These long term side effects will continue to be experience[grammar?] even after the individual ceases use of the drug. Long term use of Phencyclidine has been linked to individuals experiencing bouts of aggressive, psychotic behaviors and behavior similar to schizophrenics (Koseki T et al., 2010). From the limited research we do have, the long term side effects of Phencyclidine abuse may include:

  • Anxiety and depression
  • Memory Loss
  • Social Isolation
  • Withdrawal symptoms (cravings, confusion, aggression, chills, and depression) when ceasing the use of the drug
  • Speech difficulties
  • Hallucinations


Fortunately many of the these long term effects seem to subside after 12 months of ceasing the drug ("Long Term PCP Abuse - PAX Memphis Drug & Alcohol Rehab Center", 2020).

Below in a case study adapted from (Dominici et al., 2014).

Case Study


Describe clinical findings of patients presenting to the emergency room under the influence of Phencyclidine


This case study was conducted in a hospital emergency department with an annual census of 100,000 patients per year. Emergency doctors identified patients with possible Phencyclidine intoxication. Self reported use, or reports from bystanders were also used in this process. Data collection was completed documenting both clinical and behavioral events that transpired through the admittance in the emergency department.


Data was collected on 219 patients; 184 analyzed; two patients excluded due to incomplete date. The mean age of patients was 32.5 years with 65.2% being males. Phencyclidine use was self reported in 60.3% of patients. Of the 184 patients, 153 received a urine drug screen; 152 (98.7%) tested positive for Phencyclidine. 78.3% of patients were awake and alert on arrival, and 51.6% were oriented to self, time/date and place. Physiological parameters were the follow:

  • Heart rate 101.bpm
  • BP 146.3/ 86.3
  • Temperature 36.9 degrees
  • Pulse oximetry 98.2%

Clinical findings were the following; Retrograde amnesia in 46 (25%), Horizontal nystagmus in 118 (64.1%), vertical nystagmus in 90 (48.0%), hypertension in 87 (47.3%), and agitation in 71 (38.6%). The mean length of stay in the emergency department for all subjects was 261.1 minutes. Of the 184 patients, 152 (82.6%) discharged to home, 14 (7.6%) required admission to the hospital, 12 were referred to a crisis response center.

Conclusion of Case Study

Patients with Phencyclidine intoxication tended to be young males. The clinical signs and symptoms were; retrograde amnesia, nystagmus, hypertension and psych motor agitation. Co - use of other substances was the norm. Most patients presenting with Phencyclidine intoxication recover well and can be discharged home after a period of observation.

Quiz 4[edit | edit source]

Choose the correct answer and click "Submit".

It takes approximately ________ for the effects of PCP to onset?

1 to 2 hours
3+ hours
15 to 60 minutes

Conclusion[edit | edit source]

Phencyclidine is a hallucinogen[grammar?] drug that affects an individuals[grammar?] state of mind and emotion. When individuals use the drug it has been seen to bring intense feelings of emotions to the individual which can be positive or negative experience. Research has shown that the negative experiences of the drug outweigh any positive experiences with individuals experiencing aggressive or violent behaviour and at times long term psychosis, with long term effects lasting up to 12 months from last use. There is limited research into Phencyclidine, especially in human consumption, [grammar?] this needs to be further investigated, it would allow health professionals to have a broader understanding on how this drug affects the brain and emotions, thus a better understanding on short and long term effects and how to treat them (Sharp & Graeven, 1981).

See also[edit | edit source]

Phencyclidine (Wikipedia)

Illicit drug taking at music festivals (Book chapter, 2016)

Psychedelic drug (Wikipedia)

References[edit | edit source]

Anderson, D., & Adolphs, R. (2014). A Framework for Studying Emotions across Species. Cell, 157(1), 187-200. doi: 10.1016/j.cell.2014.03.003

Barkus, C., McHugh, S., Sprengel, R., Seeburg, P., Rawlins, J., & Bannerman, D. (2010). Hippocampal NMDA receptors and anxiety: At the interface between cognition and emotion. European Journal Of Pharmacology, 626(1), 49-56. doi: 10.1016/j.ejphar.2009.10.014

Davis, B. (1982). The PCP Epidemic: A Critical Review. International Journal Of The Addictions, 17(7), 1137-1155. doi: 10.3109/10826088209056346

Davis, J., Senghas, A., & Ochsner, K. (2009). How does facial feedback modulate emotional experience?. Journal Of Research In Personality, 43(5), 822-829. doi: 10.1016/j.jrp.2009.06.005

Dhikav, V., & Anand, K. (2012). Hippocampus in health and disease: An overview. Annals Of Indian Academy Of Neurology, 15(4), 239. doi: 10.4103/0972-2327.104323 Dominici, P., Kopec, K., Manur, R., Khalid, A., Damiron, K., & Rowden, A. (2014). Phencyclidine Intoxication Case Series Study. Journal Of Medical Toxicology, 11(3), 321-325. doi: 10.1007/s13181-014-0453-9

Domino, E., & Luby, E. (2012). Phencyclidine/Schizophrenia: One View Toward the Past, The Other to the Future. Schizophrenia Bulletin, 38(5), 914-919. doi: 10.1093/schbul/sbs011

Fox, E. (2018). Perspectives from affective science on understanding the nature of emotion. Brain And Neuroscience Advances, 2, 239821281881262. doi: 10.1177/2398212818812628

Javitt DC Zukin SR (1991). Recent advances in the phencyclidine model of schizophrenia. American Journal of Psychiatry 148, 1301–1308.

Kusljic, S., & Van Den Buuse, M. (2012). Differential role of serotonin projections from the dorsal and median raphe nuclei in phencyclidine-induced hyperlocomotion and fos-like immunoreactivity in rats. Synapse (New York, N.Y.), 66(10), 885–892.

Long Term PCP Abuse - PAX Memphis Drug & Alcohol Rehab Center. (2020). Retrieved 18 October 2020, from

Moors, A. (2009). Theories of emotion causation: A review. Cognition & Emotion, 23(4), 625-662. doi:10.1080/02699930802645739

NCJRS Abstract - National Criminal Justice Reference Service. (2020). Retrieved 17 October 2020, from

Olney JW Labruyere J Price MT (1989). Pathological changes induced in cerebrocortical neurons by phencyclidine and related drugs. Science 244, 1360–1362.

PCP (Angel Dust): Effects, Hazards & Extent of Use - (2020). Retrieved 17 October 2020, from

PCP Facts, History and Statistics | Dangers and Legality. (2020). Retrieved 17 October 2020, from

Petersen, R., & Stillman, R. (1978). Phencyclidine (PCP) abuse. Rockville, Md.: United States Department of Health, Education, and Welfare, Public Health Service, Alcohol, Drug Abuse, and Mental Health Administration, National Institute on Drug Abuse, Division of Research.

Phencyclidine. (2020). Retrieved 19 October 2020, from

Phencyclidine. (2020). Retrieved 17 October 2020,

Phencyclidine. (2016). Meyler's Side Effects of Drugs, 670-672. doi:10.1016/b978-0-444-53717-1.01253-1

Puran, A., Holstege, C., Jamison, K., & Wiegand, T. (2014). Phencyclidine. Encyclopedia Of Toxicology, 868-870.

Sharp, J., & Graeven, D. (1981). The social, behavioral, and health effects of phencyclidine (PCP) use. Journal Of Youth And Adolescence, 10(6), 487-499. doi: 10.1007/bf02087941 T, B., & A, P. (2020). Phencyclidine intoxication and adverse effects: a clinical and pharmacological review of an illicit drug. Retrieved 17 October 2020, from

Tekulve, K., Tormoehlen, L. M., & Walsh, L. (2017). Poisoning and Drug-Induced Neurologic Diseases. In Swaiman's Pediatric Neurology: Principles and Practice: Sixth Edition (pp. 1193-1204). Elsevier Inc..

Snigdha, S., Neill, J., McLean, S., Shemar, G., Cruise, L., Shahid, M., & Henry, B. (2010). Phencyclidine (PCP)-Induced Disruption in Cognitive Performance is Gender-Specific and Associated with a Reduction in Brain-Derived Neurotrophic Factor (BDNF) in Specific Regions of the Female Rat Brain. Journal Of Molecular Neuroscience, 43(3), 337-345. doi: 10.1007/s12031-010-9447-5

External links[edit | edit source]

Drugs and Human Performance Fact Sheets on Phencyclidine

Kids Health - PCP (For Teens)