Medicinal Use of Different Cannabis Strains: Results from a Large Prospective Survey in Germany

BACKGROUND

Up to now, it is unclear whether different medicinal cannabis (MC) strains are differently efficacious across different medical conditions. In this study, the effectiveness of different MC strains was compared depending on the disease to be treated.

METHODS

This was an online survey conducted in Germany between June 2020 and August 2020. Patients were allowed to participate only if they received a cannabis-based treatment from pharmacies in the form of cannabis flowers prescribed by a physician.

RESULTS

The survey was completed by n=1,028 participants. Most participants (58%) have used MC for more than 1 year, on average, 5.9 different strains. Bedrocan (pure tetrahydrocannabinol to pure cannabidiol [THC:CBD]=22:<1) was the most frequently prescribed strain, followed by Bakerstreet (THC:CBD=19:<1) and Pedanios 22/1 (THC:CBD=22:1). The most frequent conditions MC was prescribed for were different pain disorders, psychiatric and neurological diseases, and gastrointestinal symptoms. Overall, the mean patient-reported effectiveness was 80.1% (range, 0-100%). A regression model revealed no association between the patient-reported effectiveness and the variety. Furthermore, no influence of the disease on the choice of the MC strain was detected. On average, 2.1 side effects were reported (most commonly dry mouth (19.5%), increased appetite (17.1%), and tiredness (13.0%)). However, 29% of participants did not report any side effects. Only 398 participants (38.7%) indicated that costs for MC were covered by their health insurance.

CONCLUSIONS

Patients self-reported very good efficacy and tolerability of MC. There was no evidence suggesting that specific MC strains are superior depending on the disease to be treated.

Two Decades of the International Association for Cannabinoid Medicines: 20 Years of Supporting Research and Activities Toward the Medicinal Use of Cannabis and Cannabinoids

Emerged from the German Association for Cannabis as Medicine (ACM), a handful of enthusiastic medical doctors from Germany, Switzerland, and Austria supported by experts from other countries established the International Association for Cannabinoid Medicines (IACM) in March 2000. During the past 20 years until today, it evolved toward the most important scientific society for clinical research in the field of cannabis-based medicines. The overarching aim of the IACM is to advance the knowledge on cannabis, cannabinoids, the endocannabinoid system, and related topics especially with regard to their therapeutic potential, which would allow more patients to profit from a treatment with cannabis-based medicines and ease legislators to adopt their policies. To reach this goal, the IACM organizes international scientific conferences, biweekly publishes the IACM-Bulletin-currently in six different languages-reaching more than 5000 people worldwide, and is working closely together with patient associations, international partner organizations, and IACM ambassadors. In 2019, a collaborative partnership with the journal Cannabis and Cannabinoid Research was established.

An Update on Safety and Side Effects of Cannabidiol: A Review of Clinical Data and Relevant Animal Studies

Introduction: This literature survey aims to extend the comprehensive survey performed by Bergamaschi et al. in 2011 on cannabidiol (CBD) safety and side effects. Apart from updating the literature, this article focuses on clinical studies and CBD potential interactions with other drugs. Results: In general, the often described favorable safety profile of CBD in humans was confirmed and extended by the reviewed research. The majority of studies were performed for treatment of epilepsy and psychotic disorders. Here, the most commonly reported side effects were tiredness, diarrhea, and changes of appetite/weight. In comparison with other drugs, used for the treatment of these medical conditions, CBD has a better side effect profile. This could improve patients' compliance and adherence to treatment. CBD is often used as adjunct therapy. Therefore, more clinical research is warranted on CBD action on hepatic enzymes, drug transporters, and interactions with other drugs and to see if this mainly leads to positive or negative effects, for example, reducing the needed clobazam doses in epilepsy and therefore clobazam's side effects. Conclusion: This review also illustrates that some important toxicological parameters are yet to be studied, for example, if CBD has an effect on hormones. Additionally, more clinical trials with a greater number of participants and longer chronic CBD administration are still lacking.

A Conversion of Oral Cannabidiol to Delta9-Tetrahydrocannabinol Seems Not to Occur in Humans

Cannabidiol (CBD), a major cannabinoid of hemp, does not bind to CB1 receptors and is therefore devoid of psychotomimetic properties. Under acidic conditions, CBD can be transformed to delta9-tetrahydrocannabinol (THC) and other cannabinoids. It has been argued that this may occur also after oral administration in humans. However, the experimental conversion of CBD to THC and delta8-THC in simulated gastric fluid (SGF) is a highly artificial approach that deviates significantly from physiological conditions in the stomach; therefore, SGF does not allow an extrapolation to in vivo conditions. Unsurprisingly, the conversion of oral CBD to THC and its metabolites has not been observed to occur in vivo, even after high doses of oral CBD. In addition, the typical spectrum of side effects of THC, or of the very similar synthetic cannabinoid nabilone, as listed in the official Summary of Product Characteristics (e.g., dizziness, euphoria/high, thinking abnormal/concentration difficulties, nausea, tachycardia) has not been observed after treatment with CBD in double-blind, randomized, controlled clinical trials. In conclusion, the conversion of CBD to THC in SGF seems to be an in vitro artifact.

Even High Doses of Oral Cannabidol Do Not Cause THC-Like Effects in Humans: Comment on Merrick et al. Cannabis and Cannabinoid Research 2016;1(1):102-112; DOI: 10.1089/can.2015.0004

This short communication examines the question whether the experimental data presented in a study by Merrick et al. are of clinical relevance. These authors found that cannabidiol (CBD), a major cannabinoid of the cannabis plant devoid of psychotropic effects and of great interest for therapeutic use in several medical conditions, may be converted in gastric fluid into the psychoactive cannabinoids delta-8-THC and delta-9-THC to a relevant degree. They concluded that “the acidic environment during normal gastrointestinal transit can expose orally CBD-treated patients to levels of THC and other psychoactive cannabinoids that may exceed the threshold for a positive physiological response.” They issued a warning concerning oral use of CBD and recommend the development of other delivery methods. However, the available clinical data do not support this conclusion and recommendation, since even high doses of oral CBD do not cause psychological, psychomotor, cognitive, or physical effects that are characteristic for THC or cannabis rich in THC. On the contrary, in the past decades and by several groups, high doses of oral CBD were consistently shown to cause opposite effects to those of THC in clinical studies. In addition, administration of CBD did not result in detectable THC blood concentrations. Thus, there is no reason to avoid oral use of CBD, which has been demonstrated to be a safe means of administration of CBD, even at very high doses.

The Medical use of Cannabis in Germany

The author first describes the history of medical use of cannabis and its revival in the 1990s. He then provides an overview of the legal situation and how this affects doctors and patients if cannabis is prescribed or recommended as treatment. Subsequently, the state of the art of cannabis medication research is described and analyzed. Finally, the public and political discourse that arose in reaction to legal and political efforts to legalize cannabis for medical purposes is described.

The therapeutic potential of cannabis and cannabinoids

BACKGROUND

Cannabis-based medications have been a topic of intense study since the endogenous cannabinoid system was discovered two decades ago. In 2011, for the first time, a cannabis extract was approved for clinical use in Germany.

METHODS

Selective literature review.

RESULTS

Cannabis-based medications exert their effects mainly through the activation of cannabinoid receptors (CB1 and CB2). More than 100 controlled clinical trials of cannabinoids or whole-plant preparations for various indications have been conducted since 1975. The findings of these trials have led to the approval of cannabis-based medicines (dronabinol, nabilone, and a cannabis extract [THC:CBD=1:1]) in several countries. In Germany, a cannabis extract was approved in 2011 for the treatment of moderate to severe refractory spasticity in multiple sclerosis. It is commonly used off label for the treatment of anorexia, nausea, and neuropathic pain. Patients can also apply for government permission to buy medicinal cannabis flowers for self-treatment under medical supervision. The most common side effects of cannabinoids are tiredness and dizziness (in more than 10% of patients), psychological effects, and dry mouth. Tolerance to these side effects nearly always develops within a short time. Withdrawal symptoms are hardly ever a problem in the therapeutic setting.

CONCLUSION

There is now clear evidence that cannabinoids are useful for the treatment of various medical conditions.

Cannabis-associated arteritis

BACKGROUND

To investigate the hypothesis that cases of arteritis similar to thromboangiitis obliterans (TAO) and associated with the use of cannabis were caused by cannabis or THC (dronabinol), or that cannabis use is a co-factor of TAO.

PATIENTS AND METHODS

A systematic review on case reports and the literature on so-called cannabis arteritis, TAO, and cardiovascular effects of cannabinoids was conducted.

RESULTS

Fifteen reports with 57 cases of an arteritis associated with the use of cannabis and two additional case series of TAO, in which some patients also used cannabis, were identified. Clinical and pathological features of cannabis-associated arteritis do not differ from TAO and the major risk factor of TAO, tobacco use, was present in most, if not in all of these cases. The proposed pathophysiological mechanisms for the development of an arteritis by cannabis use are not substantiated.

CONCLUSIONS

The hypothesis of cannabis being a causative factor or co-factor of TAO or an arteritis similar to TAO is not supported by the available evidence. The use of the term cannabis arteritis should be avoided until or unless more convincing scientific support is forthcoming.

Developing limits for driving under cannabis

OBJECTIVE

Development of a rational and enforceable basis for controlling the impact of cannabis use on traffic safety.

METHODS

An international working group of experts on issues related to drug use and traffic safety evaluated evidence from experimental and epidemiological research and discussed potential approaches to developing per se limits for cannabis.

RESULTS

In analogy to alcohol, finite (non-zero) per se limits for delta-9-tetrahydrocannabinol (THC) in blood appear to be the most effective approach to separating drivers who are impaired by cannabis use from those who are no longer under the influence. Limited epidemiological studies indicate that serum concentrations of THC below 10 ng/ml are not associated with an elevated accident risk. A comparison of meta-analyses of experimental studies on the impairment of driving-relevant skills by alcohol or cannabis suggests that a THC concentration in the serum of 7-10 ng/ml is correlated with an impairment comparable to that caused by a blood alcohol concentration (BAC) of 0.05%. Thus, a suitable numerical limit for THC in serum may fall in that range.

CONCLUSIONS

This analysis offers an empirical basis for a per se limit for THC that allows identification of drivers impaired by cannabis. The limited epidemiological data render this limit preliminary.

The Toxicology of Cannabis and Cannabis Prohibition

The acute side effects caused by cannabis use are mainly related to psyche and cognition, and to circulation. Euphoria, anxiety, changes in sensory perception, impairment of memory and psychomotor performance are common effects after a dose is taken that exceeds an individually variable threshold. Cannabis consumption may increase heart rate and change blood pressure, which may have serious consequences in people with heart disease. Effects of chronic use may be induction of psychosis and development of dependency to the drug. Effects on cognitive abilities seem to be reversible after abstinence, except possibly in very heavy users. Cannabis exposure in utero may have negative consequences on brain development with subtle impairment of cognitive abilities in later life. Consequences of cannabis smoking may be similar to those of tobacco smoking and should be avoided. Use by young people has more detrimental effects than use by adults. There appear to be promising therapeutic uses of cannabis for a range of indications. Use of moderate doses in a therapeutic context is usually not associated with severe side effects. Current prohibition on cannabis use may also have harmful side effects for the individual and the society, while having little influence on prevalence of use. Harm is greatest for seriously ill people who may benefit from a treatment with cannabis. This makes it difficult to justify criminal penalties against patients.

The treatment of spasticity with Delta9-tetrahydrocannabinol in persons with spinal cord injury

STUDY DESIGN

Open label study to determine drug dose for a randomized double-blind placebo-controlled parallel study.

OBJECTIVES

To assess the efficacy and side effects of oral Delta(9)-tetrahydrocannabinol (THC) and rectal THC-hemisuccinate (THC-HS) in SCI patients.

SETTING

REHAB Basel, Switzerland.

METHOD

Twenty-five patients with SCI were included in this three-phase study with individual dose adjustment, each consisting of 6 weeks. Twenty-two participants received oral THC open label starting with a single dose of 10 mg (Phase 1, completed by 15 patients). Eight subjects received rectal THC-HS (Phase 2, completed by seven patients). In Phase 3, six patients were treated with oral THC and seven with placebo. Major outcome parameters were the spasticity sum score (SSS) using the Modified Ashworth Scale (MAS) and self-ratings of spasticity.

RESULTS

Mean daily doses were 31 mg with THC and 43 mg with THC-HS. Mean SSS for THC decreased significantly from 16.72 (+/-7.60) at baseline to 8.92 (+/-7.14) on day 43. Similar improvement was seen with THC-HS. We observed a significant improvement of SSS with active drug (P=0.001) in the seven subjects who received oral THC in Phase 1 and placebo in Phase 3. Major reasons for drop out were increase of pain and psychological side effects.

CONCLUSION

THC is an effective and safe drug in the treatment of spasticity. At least 15-20 mg per day were needed to achieve a therapeutic effect.

Cannabinoids

Since the discovery of an endogenous cannabinoid system, research into the pharmacology and therapeutic potential of cannabinoids has steadily increased. Two subtypes of G-protein coupled cannabinoid receptors, CB(1) and CB(1), have been cloned and several putative endogenous ligands (endocannabinoids) have been detected during the past 15 years. The main endocannabinoids are arachidonoyl ethanolamide (anandamide) and 2-arachidonoyl glycerol (2-AG), derivatives of arachidonic acid, that are produced "on demand" by cleavage of membrane lipid precursors. Besides phytocannabinoids of the cannabis plant, modulators of the cannabinoid system comprise synthetic agonists and antagonists at the CB receptors and inhibitors of endocannabinoid degradation. Cannabinoid receptors are distributed in the central nervous system and many peripheral tissues, including immune system, reproductive and gastrointestinal tracts, sympathetic ganglia, endocrine glands, arteries, lung and heart. There is evidence for some non-receptor dependent mechanisms of cannabinoids and for endocannabinoid effects mediated by vanilloid receptors. Properties of CB receptor agonists that are of therapeutic interest include analgesia, muscle relaxation, immunosuppression, anti-inflammation, antiallergic effects, improvement of mood, stimulation of appetite, antiemesis, lowering of intraocular pressure, bronchodilation, neuroprotection and antineoplastic effects. The current main focus of clinical research is their efficacy in chronic pain and neurological disorders. CB receptor antagonists are under investigation for medical use in obesity and nicotine addiction. Additional potential was proposed for the treatment of alcohol and heroine dependency, schizophrenia, conditions with lowered blood pressure, Parkinson's disease and memory impairment in Alzheimer's disease.

Pharmacology of cannabinoids

Dronabinol (Delta 9-tetrahydocannabinol, THC), the main source of the pharmacological effects caused by the use of cannabis, is an agonist to both the CB1 and the CB2 subtype of cannabinoid receptors. It is available on prescription in several countries. The non-psychotropic cannabidiol (CBD), some analogues of natural cannabinoids and their metabolites, antagonists at the cannabinoid receptors and modulators of the endogenous cannabinoid system are also promising candidates for clinical research and therapeutic uses. Cannabinoid receptors are distributed in the central nervous system and many peripheral tissues including spleen, leukocytes; reproductive, urinary and gastrointestinal tracts; endocrine glands, arteries and heart. Five endogenous cannabinoids have been detected so far, of whom anandamide and 2-arachidonylglycerol are best characterized. There is evidence that besides the two cannabinoid receptor subtypes cloned so far additional cannabinoid receptor subtypes and vanilloid receptors are involved in the complex physiological functions of the cannabinoid system that include motor coordination, memory procession, control of appetite, pain modulation and neuroprotection. Strategies to modulate their activity include inhibition of re-uptake into cells and inhibition of their degradation to increase concentration and duration of action. Properties of cannabinoids that might be of therapeutic use include analgesia, muscle relaxation, immunosuppression, anti-inflammation, anti-allergic effects, sedation, improvement of mood, stimulation of appetite, anti-emesis, lowering of intraocular pressure, bronchodilation, neuroprotection and antineoplastic effects.

IACM 2nd Conference on Cannabinoids in Medicine

The International Association for Cannabis as Medicine 2nd Conference on Cannabinoids in Medicine focused on new clinical research with cannabis and single cannabinoids (Delta(9)-tetrahydrocannabinol, CT-3) and on animal research with possible therapeutic implications. The meeting brought together basic researchers, clinicians and physicians to facilitate an exchange of knowledge and experience in this field. Even a talk by a patient with multiple sclerosis was included in a workshop on neurology. Current clinical research with cannabinoids focuses mainly on chronic pain and neurological disorders adding to accepted indications such as anorexia in AIDS-wasting and antiemetic effects in cancer chemotherapy. First results are promising and larger studies are underway or have recently been completed and are awaiting publication. New basic research opens further areas of possible uses for modulators of the endogenous cannabinoid system, including osteoporosis, cancer and inflammation. A workshop on psychiatry focused on effects of cannabis use on onset, incidence and the course of schizophrenia. Basic and clinical research shows that adolescents might be more vulnerable than adults to possible psychiatric effects of cannabinoids. It was concluded that possible side effects of cannabinoids should be taken into account but do not preclude a legitimate medical use.

Spleen involvement in Hodgkin's lymphoma: assessment and risk profile

Diagnostic laparotomy is no longer routinely performed in Hodgkin's lymphoma and noninvasive diagnosis of spleen involvement remains uncertain. In order to assess the probability of splenic involvement based on clinical parameters, we retrospectively analyzed data on patients of the German Hodgkin's Lymphoma Study Group (GHSG) who underwent staging laparotomy and for whom splenic weight and size were available. Our study included 376 patients with Hodgkin's lymphoma who underwent staging laparotomy and splenectomy according to the treatment policy of the GHSG between February 1981 and January 1993. Univariate and multivariate analyses of pretherapeutic clinical characteristics and splenic weight were performed in order to predict the probability of splenic involvement. Computed tomographic (CT) images of 25 patients were available and used to correlate radiological splenic size and pathological splenic weight. In 171 of 376 patients spleen involvement was found. Average weight of the spleens was 258 g (+/-257) ranging from 55 to 3290 g. All spleens with a weight above 2000 g showed disease involvement, while those under 150 g were never involved. In the multivariate analysis, splenic weight ( p<0.001), erythrocyte sedimentation rate ( p<0.001), and clinical stage ( p<0.01) were found to be independently prognostic for spleen involvement. Splenic weight was highly correlated with a spleen index defined as the product of length, width, and thickness measured by CT (correlation coefficient: 0.93). By applying the identified risk factors in clinically staged patients spleen involvement can be determined. Spleen weight can be estimated with the help of a spleen index. Above an index of 1000 the probability of spleen involvement is higher than 90%. This might be of outstanding importance for patients being scheduled for involved field radiation.

Pharmacokinetics and pharmacodynamics of cannabinoids

Delta(9)-Tetrahydrocannabinol (THC) is the main source of the pharmacological effects caused by the consumption of cannabis, both the marijuana-like action and the medicinal benefits of the plant. However, its acid metabolite THC-COOH, the non-psychotropic cannabidiol (CBD), several cannabinoid analogues and newly discovered modulators of the endogenous cannabinoid system are also promising candidates for clinical research and therapeutic uses. Cannabinoids exert many effects through activation of G-protein-coupled cannabinoid receptors in the brain and peripheral tissues. Additionally, there is evidence for non-receptor-dependent mechanisms. Natural cannabis products and single cannabinoids are usually inhaled or taken orally; the rectal route, sublingual administration, transdermal delivery, eye drops and aerosols have only been used in a few studies and are of little relevance in practice today. The pharmacokinetics of THC vary as a function of its route of administration. Pulmonary assimilation of inhaled THC causes a maximum plasma concentration within minutes, psychotropic effects start within seconds to a few minutes, reach a maximum after 15-30 minutes, and taper off within 2-3 hours. Following oral ingestion, psychotropic effects set in with a delay of 30-90 minutes, reach their maximum after 2-3 hours and last for about 4-12 hours, depending on dose and specific effect. At doses exceeding the psychotropic threshold, ingestion of cannabis usually causes enhanced well-being and relaxation with an intensification of ordinary sensory experiences. The most important acute adverse effects caused by overdosing are anxiety and panic attacks, and with regard to somatic effects increased heart rate and changes in blood pressure. Regular use of cannabis may lead to dependency and to a mild withdrawal syndrome. The existence and the intensity of possible long-term adverse effects on psyche and cognition, immune system, fertility and pregnancy remain controversial. They are reported to be low in humans and do not preclude legitimate therapeutic use of cannabis-based drugs. Properties of cannabis that might be of therapeutic use include analgesia, muscle relaxation, immunosuppression, sedation, improvement of mood, stimulation of appetite, antiemesis, lowering of intraocular pressure, bronchodilation, neuroprotection and induction of apoptosis in cancer cells.

Evaluating the impact of hemp food consumption on workplace drug tests

Foods containing seeds or oil of the hemp plant (Cannabis sativa L.) are increasingly found in retail stores in the U.S. The presence of delta9-tetrahydrocannabinol (THC) in these foods has raised concern over their impact on the results of workplace drug tests for marijuana. Previous studies have shown that eating hemp foods can cause screening and confirmed positive results in urine specimens. This study evaluated the impact of extended daily ingestion of THC via hemp oil on urine levels of its metabolite 11-nor-9-carboxy-delta9-tetrahydrocannabinol (THC-COOH) for four distinct daily THC doses. Doses were representative of THC levels now commonly found in hemp seed products and a range of conceivable daily consumption rates. Fifteen THC-naïve adults ingested, over four successive 10-day periods, single daily THC doses ranging from 0.09 to 0.6 mg. Subjects self-administered THC in 15-mL aliquots (20 mL for the 0.6-mg dose) of four different blends of hemp and canola oils. Urine specimens were collected prior to the first ingestion of oil, on days 9 and 10 of each of the four study periods, and 1 and 3 days after the last ingestion. All specimens were screened for cannabinoids by radioimmunoassay (Immunalysis Direct RIA Kit), confirmed for THC-COOH by gas chromatography-mass spectrometry (GC-MS), and analyzed for creatinine to identify dilute specimens. None of the subjects who ingested daily doses of 0.45 mg of THC screened positive at the 50-ng/mL cutoff. At a daily THC dose of 0.6 mg, one specimen screened positive. The highest THC-COOH level found by GC-MS in any of the specimens was 5.2 ng/mL, well below the 15-ng/mL confirmation cutoff used in federal drug testing programs. A THC intake of 0.6 mg/day is equivalent to the consumption of approximately 125 mL of hemp oil containing 5 microg/g of THC or 300 g of hulled seeds at 2 microg/g. These THC concentrations are now typical in Canadian hemp seed products. Based on our findings, these concentrations appear to be sufficiently low to prevent confirmed positives from the extended and extensive consumption of hemp foods.

[Some practice-relevant aspects of the pharmacokinetics of THC]

The pharmacokinetics of THC varies in dependence of its route of administration. Pulmonary assimilation of Cannabis (smoking, inhalation) leads to a maximum THC concentration within minutes, psychotropic effects start within seconds to a few minutes, reach a maximum after 15-30 min, and slope down within 1-2 h. In case of oral ingestion the effect sets in delayed after 30-90 min, reaches its maximum after 2-3 h and lasts about 4-8 h. Duration of action depends on measured parameters. Intestinal absorption of THC is increased by application in a lipophilic base. Cannabinoids are present in the plant mainly as pharmacologically inactive carboxylic acids (more than 95%), that are transformed into the active phenols by heating (smoking, baking). Heating of 5 min to 200 degrees C seems to be optimal.

[Results of a standardized survey on the medical use of cannabis products in the German-speaking area]

The plant Cannabis sativa has a long history of medical use in the treatment of pain and spasms, the promotion of sleep, and the suppression of nausea and vomiting. However, in the early 70s cannabis was classified in the Narcotic Acts in countries all over the world as having no therapeutic benefit; therefore, it cannot be prescribed by physicians or dispensed by pharmacists. In the light of this contradictory situation an increasing number of patients practices a self-prescription with cannabis products for relieving a variety of symptoms. An anonymous standardized survey of the medical use of cannabis and cannabis products of patients in Germany, Austria and Switzerland was conducted by the Association for Cannabis as Medicine (Cologne, Germany). During about one year 170 subjects participated in this survey; questionnaires of 128 patients could be included into the evaluation. 68% of these participants were males, 32% females, with a total mean age of 37.5 (+/- 9.6) years. The most frequently mentioned indications for medicinal cannabis use were depression (12.0%), multiple sclerosis (10.8%), HIV-infection (9.0%), migraine (6.6%), asthma (6.0%), back pain (5.4%), hepatitis C (4. 8%), sleeping disorders (4.8%), epilepsy (3.6%), spasticity (3.6%), headache (3.6%), alcoholism (3.0%), glaucoma (3.0%), nausea (3.0%), disk prolapse (2.4%), and spinal cord injury (2.4%). The majority of patients used natural cannabis products such as marihuana, hashish and an alcoholic tincture; in just 5 cases dronabinol (Marinol) was taken by prescription. About half of the 128 participants of the survey (52.4%) had used cannabis as a recreational drug before the onset of their illness. To date 14.3% took cannabis orally, 49.2% by inhalation and in 36.5% of cases both application modes were used. 72.2% of the patients stated the symptoms of their illness to have 'much improved' after cannabis ingestion, 23.4% stated to have 'slightly improved', 4.8% experienced 'no change' and 1.6% described that their symptoms got 'worse'. Being asked for the satisfaction with their therapeutic use of cannabis 60.8% stated to be 'very satisfied', 24.0% 'satisfied', 11.2% 'partly satisfied' and 4.0% were 'not satisfied'. 70.8% experienced no side effects, 26.4% described 'moderate' and 3.3% 'strong' side effects. 84.1% of patients have not felt any need for dose escalation during the last 3 months, 11.0% had to increase their cannabis dose 'moderately' and 4.8% 'strongly' in order to maintain the therapeutic effects. Thus, this survey demonstrates a successful use of cannabis products for the treatment of a multitude of various illnesses and symptoms. This use was usually accompanied only by slight and in general acceptable side effects. Because the patient group responding to this survey is presumably highly selected, no conclusions can be drawn about the quantity of wanted and unwanted effects of the medicinal use of the hemp plant for particular indications.

[The effects of cannabis and THC]

Cannabis and THC exert manifold actions on a number of organ systems. A lethal dose of THC in humans is unknown. Above the psychotropic threshold, ingestion of cannabis causes an enhanced well-being and relaxation with an intensification of ordinary sensory experiences. The most important unwanted acute psychical effects are anxiety and panic attacks. Acute somatic effects are increased heart rate, changes of blood pressure, conjunctival injection and dry mouth. Properties that might be used therapeutically comprise analgesia, muscle relaxation, sedation, increase of mood, stimulation of appetite, antiemesis, lowering of intraoccular pressure and bronchodilation. Chronic use may lead to dependency and to a mild withdrawal syndrome. The extent of possible long-term damage on psyche and cognition, immune system, fertility and pregnancy remains controversial. Marijuana can induce a schizophrenic psychosis in vulnerable persons presumably without increasing the incidence of the disease. Disturbance of immunological and hormonal functions and long-term impairment of memory, attention, and complex cognitive processes are low and do not preclude a legitimate therapeutic use.