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Harris Isbell (June 7, 1910 – December 23, 1994) was an American pharmacologist and the director of research for the
NIMH NIMH may refer to: *Nickel–metal hydride battery (NiMH), a type of electrical battery *National Institute of Mental Health, an agency of the United States government *National Institute of Medical Herbalists, a professional organisation in the Un ...
Addiction Research Center The Addiction Research Center (ARC) is a center of addiction research that was founded in 1935. It was originally based in Lexington, Kentucky, United States, housed on the rural campus of the US Public Health Service Hospital. The ARC shared the c ...
at the Public Health Service Hospital in Lexington, Kentucky from 1945 to 1963. He did extensive research on the physical and psychological effects of various drugs on humans (imprisoned narcotics offenders, see below). Early work investigated aspects of physical dependence (an important aspect of drug addiction) with opiates and barbiturates, while later work (at least partially funded by the
Central Intelligence Agency The Central Intelligence Agency (CIA ), known informally as the Agency and historically as the Company, is a civilian foreign intelligence service of the federal government of the United States, officially tasked with gathering, processing, ...
as part of the
MKUltra Project MKUltra (or MK-Ultra) was an illegal human experimentation program designed and undertaken by the U.S. Central Intelligence Agency (CIA), intended to develop procedures and identify drugs that could be used in interrogations to weak ...
project)Marks JD. 1991. ''The Search for the "Manchurian Candidate"''. W.W. Norton.Lee, MA. 1994. ''Acid Dreams: The Complete Social History of LSD''. Grove Press.Campbell ND, Olsen JP, Walden L. 2008. ''The Narcotics Farm''. Harry N. Abrams. investigated psychedelic drugs, including LSD. The research was extensively reported in academic journals such as the ''Journal of Pharmacology and Experimental Therapeutics'', ''Psychopharmacologia'', and the AMA ''Archives of Neurology and Psychiatry''.


Biography

He was born on June 7, 1910 in Arkansas to Francis Taylor Isbell and Celeste Mathews. He received his M.D. from
Tulane University School of Medicine The Tulane University School of Medicine is located in New Orleans, Louisiana, United States and is a part of Tulane University. The school is located in the Medical District of the New Orleans Central Business District. History The school wa ...
in 1934, and held various research positions before becoming head of the
Addiction Research Center The Addiction Research Center (ARC) is a center of addiction research that was founded in 1935. It was originally based in Lexington, Kentucky, United States, housed on the rural campus of the US Public Health Service Hospital. The ARC shared the c ...
(ARC) in 1945. He was awarded the US Public Health Service Meritorious Service Award in 1962; Attorney General Robert F. Kennedy praised him as "an extraordinarily able director and coordinator of multidisciplinary research" and "an outstanding investigator in his own right whose work in clinical pharmacology has exerted far-reaching influences on medical practice". After leaving the ARC in 1963, he became Professor of Medicine and Pharmacology at the
University of Kentucky The University of Kentucky (UK, UKY, or U of K) is a public land-grant research university in Lexington, Kentucky. Founded in 1865 by John Bryan Bowman as the Agricultural and Mechanical College of Kentucky, the university is one of the state ...
School of Medicine. Isbell and his associates (including
Abraham Wikler Abraham Wikler (October 12, 1910 – March 7, 1981). was an American psychiatrist and neurologist who made important discoveries in drug addiction. He was one of the first to promote a view of addiction as conditioned behavior, and made the fir ...
) published extensively on the effects of drugs (including
opiates An opiate, in classical pharmacology, is a substance derived from opium. In more modern usage, the term ''opioid'' is used to designate all substances, both natural and synthetic, that bind to opioid receptors in the brain (including antagonist ...
, synthetic opioids, barbiturates, alcohol, amphetamine,
ibogaine Ibogaine is a naturally occurring psychoactive substance found in plants in the family Apocynaceae such as '' Tabernanthe iboga'', '' Voacanga africana'', and '' Tabernaemontana undulata''. It is a psychedelic with dissociative properties. Pre ...
, multiple
psychedelics Psychedelics are a subclass of hallucinogenic drugs whose primary effect is to trigger non-ordinary states of consciousness (known as psychedelic experiences or "trips").Pollan, Michael (2018). ''How to Change Your Mind: What the New Science of ...
, and
THC Tetrahydrocannabinol (THC) is the principal psychoactive constituent of cannabis and one of at least 113 total cannabinoids identified on the plant. Although the chemical formula for THC (C21H30O2) describes multiple isomers, the term ''THC' ...
) on human subjects, with over 125 publications. Among their experimental results were the qualitative and quantitative documentation of
physical dependence Physical dependence is a physical condition caused by chronic use of a tolerance-forming drug, in which abrupt or gradual drug withdrawal causes unpleasant physical symptoms. Physical dependence can develop from low-dose therapeutic use of certai ...
on barbiturates, physical dependence on alcohol, tolerance to amphetamine, the clinical use of opiate
antagonists An antagonist is a character in a story who is presented as the chief foe of the protagonist. Etymology The English word antagonist comes from the Greek ἀνταγωνιστής – ''antagonistēs'', "opponent, competitor, villain, enemy, ri ...
(e.g., nalorphine/Nalline and naloxone/Narcan) as treatment for opiate overdoses,Jasinski DR. ''Clinical Aspects of Opiate Antagonists and Partial Agonists''. pp 118-124 in Martin and Isbell(1978). the ability of
methadone Methadone, sold under the brand names Dolophine and Methadose among others, is a synthetic opioid agonist used for chronic pain and also for opioid dependence. It is used to treat chronic pain, and it is also used to treat addiction to heroi ...
to alleviate opiate
withdrawal Withdrawal means "an act of taking out" and may refer to: * Anchoresis (withdrawal from the world for religious or ethical reasons) * ''Coitus interruptus'' (the withdrawal method) * Drug withdrawal * Social withdrawal * Taking of money from a ban ...
symptoms, rapid tolerance but lack of physical dependence with
LSD Lysergic acid diethylamide (LSD), also known colloquially as acid, is a potent psychedelic drug. Effects typically include intensified thoughts, emotions, and sensory perception. At sufficiently high dosages LSD manifests primarily mental, vi ...
,
cross-tolerance Cross-tolerance is a phenomenon that occurs when tolerance to the effects of a certain drug produces tolerance to another drug. It often happens between two drugs with similar functions or effects—for example, acting on the same cell receptor o ...
between LSD and
psilocybin Psilocybin ( , ) is a naturally occurring psychedelic prodrug compound produced by more than 200 species of fungi. The most potent are members of the genus ''Psilocybe'', such as '' P. azurescens'', '' P. semilanceata'', and '' P.&nbs ...
, and the ability of pure THC to cause marijuana-like effects. New pharmaceutical substances were assayed (in the prisoner population) for their abuse and
addiction Addiction is a neuropsychological disorder characterized by a persistent and intense urge to engage in certain behaviors, one of which is the usage of a drug, despite substantial harm and other negative consequences. Repetitive drug use o ...
(
substance dependence Substance dependence, also known as drug dependence, is a biopsychological situation whereby an individual's functionality is dependent on the necessitated re-consumption of a psychoactive substance because of an adaptive state that has develope ...
) potential (medications for pain, cough, and diarrhea were of particular concern),Fraser, HF. ''Methods for Evaluating the Overall Abuse Liability of Weak Opiate-like Drugs''. pp 42-62 in Martin and Isbell(1978). and this information was utilized by groups such as the
World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of ...
.Campbell ND. 2007
''Discovering Addiction: The Science and Politics of Substance Abuse Research''
University of Michigan Press.
Other work at the ARC during Isbell's tenure included psychological aspects of human opiate addiction (e.g., re-arousal of craving after abstinence upon return to the addiction environment, i.e. a "conditioned" response),Wikler A. ''Neurophysiological and Neuropsychiatric Aspects of Opioid Dependence''. pp 63-88 in Martin and Isbell(1978).
EEG Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The biosignals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocortex ...
studies of mental activity during drug use (including mescaline),Kay DC. ''Electroencephalographic and Sleep Studies of Psychoactive Drugs ''. pp 140-151 in Martin and Isbell(1978). and animal studies. (A detailed annotated bibliography of ARC research was published in 1978.) Isbell died on December 23, 1994 in Lexington, Kentucky.


Research

Areas of interest described in Isbell's published work include physical and psychological effects of individual substances (including potential for dependence and addiction), ways to mitigate withdrawal symptoms (e.g., methadone therapy), the development of reliable rating methods and questionnaires for subjective drug effects (the Addiction Research Center Inventory),Haertzen, CA. ''Clinical Psychological Studies''. pp 155-168 in Martin and Isbell(1978).Isbell, Belleville, Haertzen, Jasinski, Martin. ''Round Table Discussion: Measurement of Subjective Responses to Psychoactive Drugs and Personality Characteristics of Narcotic Addicts''. pp 200-204 in Martin and Isbell(1978). cross-drug comparisons, drug tolerance, and classification of drug groups (based on both the physiological and the subjective effects of a drug, as well as its cross-tolerance with other drugs).


"Volunteer" subjects

The subjects in Isbell's experiments are described as "volunteers"; they were recruited from the associated Lexington Public Health Service Hospital. The hospital was a US Government facility for treating drug abuse; some patients were sentenced drug offenders, while others voluntarily entered for treatment. The subjects in ARC experiments were all incarcerated male narcotics offenders with a history of drug addiction; subjects signed a simple "Consent Form". Subjects were motivated by payment in the form of drugs (usually opiates); this fact is not documented in the published research articles. The separate living environment within the ARC for experimental subjects (e.g., the possibility of having a small private room) was also a motivation. The use of prison subjects for these sorts of experiments (and the nature of payment) would be difficult or impossible to justify by current human subjects and informed consent standards. The potential for coercion in a prison environment is one concern; providing drugs (whether as experimental substances or as payment) to abstinent addicts in a treatment center is another. (See Campbell (2007) for a detailed discussion of ethical and historical aspects of the ARC subject protocols.) Subjects in the experiments are described as physically healthy former drug addicts who were not psychotic, although they often were described as having "character disorders or inadequate personalities" (this diagnosis appears to be based on
MMPI The Minnesota Multiphasic Personality Inventory (MMPI) is a standardized psychometric test of adult personality and psychopathology. Psychologists and other mental health professionals use various versions of the MMPI to help develop treatment ...
test evaluation). Subjects in some of the more extreme psychedelic experiments (LSD doses for 77 days in a row) were all "Negro males", though this is not a regular pattern (e.g., the 5 subjects in the similarly extreme 1950 barbiturate study described below were all white males). In spite of the risky nature of some of the experiments (e.g., inducing addiction to opiates, alcohol, barbiturates, or new minimally tested pharmaceuticals, and then forcing immediate and severe withdrawal), there were apparently no fatalities, though there was at least one close call. Subjects sometimes dropped out in the middle of an experiment, although in one reported case a subject who wished to drop out after a severe negative reaction to a 180 microgram LSD dose ("He felt that he would die or would become permanently insane") required "considerable persuasion" to continue.


General methodology

The studies took place in a dedicated experimental ward. Given the hospital context, medical personnel were readily available. In general, the methodology appears scientifically sound (e.g., proper balancing of experimental conditions, within-subjects designs, single (sometimes double) blind procedures as appropriate, placebo conditions, careful documentation of the experimental procedures, appropriate awareness of potential confounding factors, etc.), although the small number of subjects in some of the experiments is a statistical concern. The general methodology for the addiction studies consisted of first getting subjects drug-free (with apparent exceptions for
cigarettes A cigarette is a narrow cylinder containing a combustible material, typically tobacco, that is rolled into thin paper for smoking. The cigarette is ignited at one end, causing it to smolder; the resulting smoke is orally inhaled via the opp ...
and
coffee Coffee is a drink prepared from roasted coffee beans. Darkly colored, bitter, and slightly acidic, coffee has a stimulating effect on humans, primarily due to its caffeine content. It is the most popular hot drink in the world. Seeds of ...
), and then attempting to induce addiction by regular administration (orally or injected) of the substance of interest. Addiction was determined by the occurrence of abstinence symptoms when administration of the substance stopped. Sometimes a different substance (e.g., methadone) would be administered at the peak of withdrawal to determine if it alleviated symptoms. Following the evaluation of this
cold turkey "Cold turkey" refers to the abrupt cessation of a substance dependence and the resulting unpleasant experience, as opposed to gradually easing the process through reduction over time or by using replacement medication. Sudden withdrawal from dru ...
withdrawal, subjects were then usually more gradually weaned off of the substance being tested. Isbell also evaluated the "euphoric" effect of various drugs (typically opioids), evaluating various doses to see if they induced similar effects (e.g., talkativeness, comfort in the experimental situation, sedation in high doses) as 30 mg of morphine. cited in, The ability to induce euphoria is sometimes/often considered to be a component of addiction liability. In the psychedelic studies, subjects had the choice of staying in an individual room or mingling with other subjects in a common area. Observations and measurements were taken before the substance of interest was ingested, and hourly thereafter (following a 10-minute rest in bed). Physical measurements included pulse, blood pressure, rectal temperature, kneejerk reflex sensitivity, and pupil diameter (opiates cause constriction (
miosis Miosis, or myosis (), is excessive constriction of the pupil.Farlex medical dictionary
citing: ...
) while LSD causes dilation ( mydriasis)). Psychological measurements consisted of a self-evaluation form with multiple statements (e.g., "I am confused"), as well as evaluation by experienced and trained observers. Some subjects had negative reactions to LSD (as noted above), but others found the experience "pleasant", or even "dearly loved" it as long as the dosage was not too high (less than 2 micrograms per kilogram of body weight).Isbell, H. ''Clinical Research 1944-1963''. pp 27-41 in Martin and Isbell(1978).


Opioids

Isbell and associates published a number of studies on
morphine Morphine is a strong opiate that is found naturally in opium, a dark brown resin in poppies (''Papaver somniferum''). It is mainly used as a pain medication, and is also commonly used recreationally, or to make other illicit opioids. T ...
, methadone and assorted
analgesics An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It ...
; much of this work was motivated by the search for a "nonaddicting analgesic" (that is, a compound with the pain-relieving capabilities of morphine, but without the
opioid dependence Opioid use disorder (OUD) is a substance use disorder characterized by cravings for opioids, continued use despite physical and/or psychological deterioration, increased tolerance with use, and withdrawal symptoms after discontinuing opioids. Op ...
issues). Many opiate derivatives and synthetic opioids were tested for addiction and abuse potential. Isbell and Vogel (1949) investigated
methadone Methadone, sold under the brand names Dolophine and Methadose among others, is a synthetic opioid agonist used for chronic pain and also for opioid dependence. It is used to treat chronic pain, and it is also used to treat addiction to heroi ...
, a synthetic opioid developed in Germany in 1937. They found that intravenous methadone had similar subjective effects as morphine and heroin, and induced physical dependence with chronic use. However, the withdrawal symptoms were significantly milder than with morphine. Administration of methadone during morphine withdrawal alleviated withdrawal symptoms, and methadone was reasonably effective when taken orally. This combination of characteristics led them to propose methadone administration as a way of facilitating morphine withdrawal.


Barbiturates

Isbell ''et al''. (1950) did a controlled experiment (no other drugs involved, and proper nutrition) on the effects of chronic barbiturate administration. 5 non-epileptic subjects were given slowly increasing doses of
secobarbital Secobarbital (as the sodium salt, originally marketed by Eli Lilly and Company for the treatment of insomnia, and subsequently by other companies as described below, under the brand name Seconal) is a short-acting barbiturate derivative drug that ...
,
pentobarbital Pentobarbital (previously known as pentobarbitone in Britain and Australia) is a short-acting barbiturate typically used as a sedative, a preanesthetic, and to control convulsions in emergencies. It can also be used for short-term treatment of i ...
, or
amobarbital Amobarbital (formerly known as amylobarbitone or sodium amytal as the soluble sodium salt) is a drug that is a barbiturate derivative. It has sedative-hypnotic properties. It is a white crystalline powder with no odor and a slightly bitter taste. ...
to a point of obvious intoxication over a period of more than 73 days. Both the nature of the intoxication and the nature of the withdrawal symptoms are described as similar to chronic alcohol use. Intoxication symptoms included confusion, poor judgment, hostility, and motor incoordination. Upon abrupt withdrawal of barbiturates, initial symptoms included tremor, anxiety, weakness, and vomiting, followed by convulsion, delirium, and hallucinations.


Alcohol

Isbell ''et al''. (1955) demonstrated that alcohol causes physical dependence; that is, cessation of alcohol consumption in a chronic user can cause significant physical withdrawal symptoms. Subjects were abstinent drug addicts; some but not all had a history of heavy alcohol use. Out of 10 initial subjects, 6 subjects were successfully kept in a state of constant moderate intoxication (still able to walk) for a period from 48–87 days. Subjects were given controlled oral doses of alcohol throughout the day from 6am until midnight, and a booster dose around 3am; the total consumption per subject was in the range of a quart of 80-proof liquor per day. All subjects were provided with a healthy diet in addition to the alcohol. Withdrawal of alcohol at the end of the intoxication period produced tremors and weakness in all 6 subjects. Two subjects suffered convulsions, and delirium or hallucinations (audio or visual) occurred in 4 of the 6 subjects. Given these withdrawal symptoms, Isbell ''et al''. (1955) made some proposals for safely managing alcohol withdrawal.


Psychedelics

Starting in 1956, Isbell and associates published studies on LSD, psilocybin,
psilocin Psilocin (also known as 4-HO-DMT, 4-hydroxy DMT, psilocine, psilocyn, or psilotsin) is a substituted tryptamine alkaloid and a serotonergic psychedelic substance. It is present in most psychedelic mushrooms together with its phosphorylated cou ...
, DMT,
bufotenine Bufotenin (5-HO-DMT, bufotenine) is a tryptamine derivative - more specifically, a DMT derivative - related to the neurotransmitter serotonin. It is an alkaloid found in some species of toads (especially the skin), mushrooms and plants. The nam ...
, morning glory seeds (
ololiuqui ''Ipomoea corymbosa'' is a species of morning glory, native throughout Latin America from Mexico as far south as Peru and widely naturalised elsewhere. Its common names include Christmasvine, Christmaspops, and snakeplant. Description and names ...
), and mescaline; these substances were sometimes described as "
psychotomimetic A drug with psychotomimetic (also known as psychotogenic) actions mimics the symptoms of psychosis, including delusions and/or delirium, as opposed to only hallucinations. Psychotomimesis is the onset of psychotic symptoms following the administrati ...
". LSD and psilocybin for many of the experiments was supplied by
Sandoz Novartis AG is a Swiss-American multinational pharmaceutical corporation based in Basel, Switzerland and Cambridge, Massachusetts, United States (global research).name="novartis.com">https://www.novartis.com/research-development/research-loca ...
Pharmaceuticals (both of these substances were legal at the time). According to a 1986 interview with Isbell, the psychedelics research was initiated by an explicit CIA request.


LSD

* Isbell ''et al''. (1956) motivated their study of LSD by the superficial similarities between the LSD state (viewed as a temporary "reversible psychosis") and
schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social wit ...
, as well as the previous findings of interactions between LSD and the endogenous neurotransmitter serotonin. A dosage of 1-2 micrograms per kilogram of body weight was determined to induce "striking effects" (mood change, perceptual distortion, pupil dilation). Four experiments then quantified tolerance effects (the extent to which repeated doses of LSD cause a reduction in the effect of a subsequent dose). Experiment 4 included 77 consecutive days with doses of 1.55 micrograms/kg (corresponding to a dose of 140 micrograms for someone weighing 200 pounds), although the full sequence of LSD doses was at least a week or two longer than this due to the tolerance protocol. Tolerance to LSD developed rapidly; by day 3 the subjective effects were significantly lessened, and later in the experiments subjects simply read and watched TV normally. In the middle of the experiment, even a quadruple dose (600 micrograms or so) had little effect. Tolerance also disappeared rapidly; after no LSD had been given for 3 days, a subsequent dose again had a large effect. There were no abstinence symptoms after LSD administration stopped (i.e., no physical dependence). * Isbell ''et al''. (1956) also concluded that the LSD reaction "had only a superficial resemblance to the chronic forms of any of the major psychoses". * Isbell and Logan (1957) reported that
chlorpromazine Chlorpromazine (CPZ), marketed under the brand names Thorazine and Largactil among others, is an antipsychotic medication. It is primarily used to treat psychotic disorders such as schizophrenia. Other uses include the treatment of bipolar di ...
(Thorazine) could either block or reverse the effects of LSD.
Azacyclonol Azacyclonol (trade names Ataractan, Calmeran, Frenoton, Frenquel, Psychosan), also known as γ-pipradrol, is a drug which is an ataractive; an agent which diminishes hallucinations in psychotic individuals. It has also been called a tranquiliz ...
had no effect, while pre-treatment with
reserpine Reserpine is a drug that is used for the treatment of high blood pressure, usually in combination with a thiazide diuretic or vasodilator. Large clinical trials have shown that combined treatment with reserpine plus a thiazide diuretic reduces m ...
augmented the effects of LSD (though in a manner described as "unpleasant"). Isbell et al. (1959b) reported that pre-treatment with scopolamine (an acetylcholine antagonist),
phenoxybenzamine Phenoxybenzamine (marketed under the trade names Dibenzyline and Dibenyline) is a non-selective, irreversible alpha blocker. Uses It is used in the treatment of hypertension, and specifically that caused by pheochromocytoma. It has a slower ons ...
(an adrenergic alpha blocker) or "BAS" (a 5-methoxytryptamine based serotonin antagonist) had little effect on a subsequent LSD dose. They attempt to explain these results within the neurotransmitter ("neurohumors") knowledge of the period.


Psilocybin

* Isbell (1959) reported that psilocybin had physical and psychological effects similar to LSD, although psilocybin had a shorter duration and much less potency for a given dosage. * Isbell ''et al''. (1961) found that 12 days treatment with LSD induced tolerance to either LSD or psilocybin (lessened response on pupil dilation and the psychological measures), and that psilocybin also induced tolerance to both LSD and psilocybin. This cross-tolerance supported the hypothesis that the two substances at least partially share their mechanism of action.


Other

* Wolbach ''et al''. (1962) reported that mescaline and LSD had similar effects (although with different time course and potency), that direct tolerance could be induced by mescaline, and that each substance induced cross-tolerance to the other. This was particularly interesting, since LSD (and psilocybin) are
indole Indole is an aromatic heterocyclic organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other c ...
compounds, while mescaline is not. * Contrasting with the psilocybin and mescaline results, Isbell ''et al''. (1964) found that tolerance to
intramuscular Intramuscular injection, often abbreviated IM, is the injection of a substance into a muscle. In medicine, it is one of several methods for parenteral administration of medications. Intramuscular injection may be preferred because muscles have ...
LSD did not provide tolerance to an intramuscular injection of the indole hallucinogen DMT. * Isbell ''et al''. (1959c) investigated the psychological and physical effects of 13 different congeners of LSD, and correlated these effects with their potency as a serotonin antagonist in smooth muscle. With the exception of "
ALD-52 ALD-52, also known as 1-acetyl-LSD, is a chemical analogue of lysergic acid diethylamide (LSD). It was originally discovered by Albert Hofmann in 1957 but was not widely studied until the rise in popularity of psychedelics in the 1960s. Effec ...
", all of the substances were less potent than LSD. There was low correlation between the smooth muscle and the "psychotomimetic" effects.


THC (marijuana)

Starting in 1967, Isbell and associates published a few studies on THC and marijuana (cannabis). * Isbell ''et al''. (1967) reported that pure
THC Tetrahydrocannabinol (THC) is the principal psychoactive constituent of cannabis and one of at least 113 total cannabinoids identified on the plant. Although the chemical formula for THC (C21H30O2) describes multiple isomers, the term ''THC' ...
(which had only recently been chemically isolated with its chemical structure identified) had marijuana-like effects (e.g., increased pulse rate (
tachycardia Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ( ...
) and altered time sense), whether smoked or taken orally. A number of other isolated compounds present in marijuana (
cannabidiol Cannabidiol (CBD) is a phytocannabinoid discovered in 1940. It is one of 113 identified cannabinoids in cannabis plants, along with tetrahydrocannabinol (THC), and accounts for up to 40% of the plant's extract. , clinical research on CBD in ...
(CBD),
cannabichromene Cannabichromene (CBC), also called cannabichrome, cannanbichromene, pentylcannabichromene or cannabinochromene, is an anti-inflammatory which may contribute to the pain-killing effect of cannabis. It is one of the hundreds of cannabinoids found i ...
) did not show these effects. * Isbell and Jasinski (1969) compared LSD (1.5 micrograms per kilogram of body weight, injected intramuscularly) and smoked THC (225 or 250 micrograms per kilogram of body weight, added to a tobacco cigarette). Physical symptoms were quite different (e.g., tachycardia with THC, dilated pupils with LSD), and tolerance to LSD did not cause tolerance to THC, suggesting different mechanisms of action. Their data do not show a statistical difference in the psychological effects of the two substances; this is somewhat surprising since
cannabis ''Cannabis'' () is a genus of flowering plants in the family Cannabaceae. The number of species within the genus is disputed. Three species may be recognized: '' Cannabis sativa'', '' C. indica'', and '' C. ruderalis''. Alternative ...
is not usually considered to be a psychedelic drug. Whether this result is due to the small number of subjects, an inappropriate rating scale, the use of pure THC, or an exceedingly high THC dose (they report that some subjects had "hallucinations", and two subjects withdrew after experiencing "psychotic reactions" to THC) is unclear. * Jasinski, Haertzen, and Isbell (1971) describe some of the subjective and physiological effects of the synthetic cannabinoids
parahexyl Parahexyl (Synhexyl, n-hexyl-Δ3-THC, (C6)-Δ6a(10a)-THC) is a synthetic homologue of THC which was invented in 1941 during attempts to elucidate the structure of Δ9-THC, one of the active components of cannabis. Parahexyl is similar in both st ...
and
dimethylheptylpyran Dimethylheptylpyran (DMHP, 3-(1,2-dimethylheptyl)-Δ6a(10a)-THC, 1,2-dimethylheptyl-Δ3-THC, A-40824, or EA-2233) is a synthetic analog of THC, which was invented in 1949 during attempts to elucidate the structure of Δ9-THC, one of the act ...
. Isbell also investigated dosage effects of THC, and reported that low doses (4–6 mg) produced a pleasurable state (euphoria, perceptual distortion, and change of mood); this dosage was described by subjects as "good reefer". However, higher doses (18 milligrams of THC) reliably produced what Isbell referred to as a "psychotic reaction" (e.g., "all of a sudden
he subject He or HE may refer to: Language * He (pronoun), an English pronoun * He (kana), the romanization of the Japanese kana へ * He (letter), the fifth letter of many Semitic alphabets * He (Cyrillic), a letter of the Cyrillic script called ''He'' ...
was on a trip and watching his own burial. The smoker will swear that what hit him never came from marijuana"). Isbell also commented on the potency of street marijuana of that time ("the local grass is probably pretty weak stuff").


Drug policy

In 1951 Isbell testified to Congress before the passage of the
Boggs Act of 1952 The Boggs Act of 1951 amended the Narcotic Drugs Import and Export Act and set mandatory sentences for drug convictions. A first offense conviction for marijuana possession carried a minimum sentence of 2 to 10 years and a fine of up to $20,000 ...
that "smoking marijuana has no unpleasant aftereffects, no dependence is developed on the drug, and the practice can easily be stopped at any time." Isbell (1971b) (p 903) provides a liberal view of drug policy. He observes that the drug laws of the time are "excessively rigid and extremely punitive", and have not had any proven effect on the drug problem. He then states that "simple possession of a drug for one's own use should be a civil offense punishable only by a fine", and suggests the possibility that marijuana of low or moderate potency could be legalized and regulated like tobacco, while also observing that maintenance on barbiturates, cocaine, or amphetamine would not be "pharmacologically sound". However, Isbell rejected removing controls on marijuana, which would "open the way to more potent stuff" such as hashish, with the consequent risk of high-dose effects.


References

{{DEFAULTSORT:Isbell, Harris 1910 births 1994 deaths American pharmacologists Psychedelic drug research Medical experimentation on prisoners Project MKUltra Human subject research in the United States Cannabis law reform in the United States Tulane University School of Medicine alumni University of Kentucky faculty