Smokin Moose
Fallen Cannabis Warrior & Ex Moderator
Please excuse the misaligned structure in some of this post. I have copied it from a pdf document, which can be viewed in it's original format here, with associated tables which have been omitted because of formatting problems. HOME OFFICE CANNABIS POTENCY STUDY 2008
HOME OFFICE CANNABIS POTENCY STUDY 2008
This study was funded by the Home Office. It arose from a recommendation
in the 2006 Cannabis report of the Advisory Council on the Misuse of Drugs (ACMD).
The proportion of herbal cannabis has increased markedly in recent years.
In 2002 it was estimated that it represented around 30% of police seizures
of cannabis, but by 2004/5 had reached 55%.
Twenty-three Police Forces in England and Wales participated in the study.
Forces were requested to submit samples confiscated from street-level users.
In early 2008, they submitted 2,921 samples for analysis to either the Forensic Science Service Ltd (FSS) or LGC Forensics at Culham (LGC F).
Initial laboratory examination showed that 80.8% were herbal cannabis and
15.3% were cannabis resin. The remaining 3.9% were either indeterminate or
not cannabis.
Microscopic examination of around two-thirds of the samples showed that over 97% of the herbal cannabis had been grown by intensive methods (sinsemilla).
The remainder was classed as traditional imported herbal cannabis.
Regional variations were found in the market share of herbal cannabis. Thus
North Wales, South Wales, Cleveland and Devon and Cornwall submitted
proportionately fewer herbal cannabis samples, whereas Essex, Metropolitan
and Avon and Somerset submitted proportionately more. These differences
were statistically significant at the 0.1% confidence interval.
The mean THC concentration (potency) of the sinsemilla samples was 16.2%
(range = 4.1 to 46%). The median potency was 15.0%, close to values reported by others in the past few years.
The mean THC concentration (potency) of the traditional imported herbal
cannabis samples was 8.4% (range = 0.3 to 22%); median = 9.0%. Only a very small number of samples were received and analysed.
The mean potency of cannabis resin was 5.9% (range = 1.3 to 27.8%). The
median = 5.0% was typical of values reported by others over many years.
Cannabis resin had a mean CBD content of 3.5% (range = 0.1 to 7.3%), but
the CBD content of herbal cannabis was less than 0.1% in nearly all cases.
There was a weak, but statistically-significant, correlation (r = 0.48; N = 112;
P < 0.001) between the THC and the CBD content of resin.
INTRODUCTION
Herbal cannabis and cannabis resin are the most widely-misused illicit substances in the UK. For many years, herbal cannabis was imported into the UK from the Caribbean, West Africa and Asia. It is often seen in the form of compressed brown vegetable matter containing seeds and stalks (Figure 1). Domestic production of intensively-cultivated herbal cannabis started in around 1990. It has been grown indoors from selected seed varieties and propagation of female plant cuttings using artificial lighting, heating, and control of day-length. This material is known as sinsemilla (without seeds; Figure 2). It consists mostly of the flowering tops of female plants, and is easily distinguished from the imported material. Cannabis resin (Figure 3) has been imported mostly from North Africa. The potency of cannabis is defined as the concentration (%) of Δ9-tetrahydrocannabinol (THC), the major active principle of the cannabis plant. Apart from THC, cannabis and cannabis resin contain many other so-called cannabinoids. One of these (cannabidiol, CBD) has attracted recent interest because it is believed to show anti-psychotic properties.
In 2006, the Advisory Council on the Misuse of Drugs (ACMD) reviewed the
classification of cannabis (Reference 1). One of the recommendations was that a further study should be carried out to determine the market share of different types of cannabis and their potencies. In view of current scientific interest in the role of CBD, it was decided that this should also be measured.
The Home Office funded the project. This included paying the forensic providers to establish the methodology using internal THC and CBD standards and to exchange samples for the comparison and harmonisation of the method for the determination of THC and CBD concentrations. The numbers of samples examined was then limited by the funds available.
In late 2007, police forces in England and Wales were invited to participate in a cannabis study. For administrative reasons, forces in Scotland and Northern Ireland were not involved. Police were requested to submit samples of cannabis confiscated from street-level users when issuing a warning and submit them to their usual service provider for laboratory examination. Samples from the Metropolitan Police were sent to both FSS and LGC Forensics. These samples were separate from those sent to laboratories for evidential purposes. There was no cost to the forces except the effort of administering the exercise.
On receipt at the laboratories, samples were weighed and visually examined by experts to determine if they were herbal cannabis, cannabis resin or something else (e.g. mixture, pipe, grinder, white powder). Also at this stage, many samples were identified as being too small for full analysis. A random selection of herbal cannabis samples was then submitted for more detailed microscopic examination to distinguish sinsemilla from traditional imported cannabis.
Herbal cannabis is an non-homogeneous product. The active constituents are
produced by secretions of glandular trichomes, most of which are situated on the bracts of the female flowers. For this reason, leaves and stalk contain little THC.
Although cannabis resin is more homogeneous, atmospheric oxidation of THC
causes the concentration of THC to be lower in the outer surface of a resin block than in the middle. Because the samples were small, it was agreed that the whole would be used for quantitative analysis to avoid errors caused by sample inhomogeneity.
Of the resin, sinsemilla and traditional imported samples, further random samples were examined to determine the THC and CBD content. The two laboratories used a similar analytical procedure that incorporated shared cannabis reference standards to ensure consistency. The homogenised samples were extracted with ethanol containing the internal standard androstenedione. The concentrations of total THC (THC and THC acid) and CBD were determined using either gas-chromatography or gas-chromatography coupled to mass-spectrometry with THC and CBD as external standards.
RESULTS
Twenty-three Police Forces in England and Wales participated in the study. In early 2008, they submitted 2,921 samples for analysis to either the Forensic Science Service Ltd (FSS) or LGC Forensics at Culham (LGC F).
The numbers of samples from each force should not be seen as a measure of the ‘cannabis problem’ in their area. For operational reasons some forces chose to send in material from only one Borough Command Unit or from one of several forces collection points. Some forces experienced internal logistics problems; others were very enthusiastic and sent in everything received during the trial period.
Initial laboratory examination showed that 80.8% were herbal cannabis and 15.3% were cannabis resin.
The remaining 3.9% were either indeterminate or not cannabis. The composition of samples for each police force is set out in Table 1; the two laboratories are shown as Lab 1 and Lab 2.
The weight of samples submitted was 4-5g, and typical of what might be termed street-level amounts.
Of the 2,352 samples of herbal cannabis, further examination of around two thirds of the samples showed that over 97% had been grown by intensive methods and were classified as sinsemilla. The remainder were classed as traditional imported herbal cannabis.
Regional variations were found in the market share of herbal cannabis. Thus North Wales, South Wales, Cleveland and Devon and Cornwall submitted proportionately fewer herbal cannabis samples, whereas Essex, Metropolitan and Avon and Somerset submitted proportionately more (Figure 4). These differences were statistically significant (Chi-squared test) at the 0.1% confidence interval. Figure 4 excludes those few samples that could not be classified as either herbal cannabis or cannabis resin on initial examination.
Following the second stage of analysis, where herbal cannabis samples were subdivided into those that were or were not sinsemilla, it was found that the proportion of sinsemilla was high in all force areas (Figure 5).
Figure 6 shows the distribution of the potency in the samples examined. The mean THC concentration in sinsemilla samples was 16.2% (range = 4.1 to 46); the median was 15.0%. The mean THC concentration in traditional imported herbal cannabis samples was 8.4% (range = 0.3 to 22%); median = 9.0%. The number of traditional imported herbal cannabis samples received and analysed was small. The mean potency of cannabis resin was 5.9% (range = 1.3 to 27.8), median = 5.0%.
Figure 7 shows the distribution of CBD in cannabis resin. The mean CBD content was 3.5% (range = 0.1 to 7.3), but the CBD content of herbal cannabis was less than 0.1% in nearly all cases.
Figure 8 shows all THC and CBD data plotted as a scatter diagram. There was a weak, but statistically- significant, correlation (r = 0.48; N = 112; P < 0.001) between the THC and the CBD content of resin.
It will be seen from Figure 8 that three samples of herbal cannabis had anomalously high CBD values. The reason for this is not understood.
For both sinsemilla and cannabis resin, small differences were found in the median potencies for samples examined by the two laboratories (Table 3). However, these may have arisen from differences in the potency of cannabis in different geographical areas, as reported by Potter et al. (Reference 3). The laboratories had harmonised their methods and exchanged test samples so the results were comparable.
The proportion of herbal cannabis has increased markedly in recent years. In 2002 it was estimated that it represented around 30% of police seizures of cannabis (Reference 2), but by 2004/5 (Reference 3) this had increased to 55%. In the present study, herbal cannabis accounted for over 80% of all cannabis seized by the police on the street when giving a warning. Furthermore, almost all of that material was sinsemilla. There has been a decline in the prevalence of cannabis resin, and traditional imported herbal cannabis is now rarely seen (Table 2). Some sinsemilla is imported from other European countries and some is domestically-produced.
This rise in the market share of herbal cannabis over the past six years has also been reported in samples submitted to the FSS (Reference 4) and LGC Forensics (Reference 5) for evidential purposes, although they may be less representative of what is available at street level.
The median potency of sinsemilla in this study (15.0%) was only marginally greater than the median value (13.98%) reported by Potter et al. (Reference 3) for samples collected in 2004/5. Since 1990, when intensively-grown cannabis first appeared in the UK its potency has slowly increased, but this appears to have stabilised. By contrast, the mean/median potency of cannabis resin and imported herbal cannabis has remained largely unchanged over many years (Reference 2). Although the potency of sinsemilla is, on average, 2-3 times that of imported herbal cannabis or cannabis resin, the various populations show considerable overlap (Figure 6).
See pdf document to continue reading HOME OFFICE CANNABIS POTENCY STUDY 2008
HOME OFFICE CANNABIS POTENCY STUDY 2008
This study was funded by the Home Office. It arose from a recommendation
in the 2006 Cannabis report of the Advisory Council on the Misuse of Drugs (ACMD).
The proportion of herbal cannabis has increased markedly in recent years.
In 2002 it was estimated that it represented around 30% of police seizures
of cannabis, but by 2004/5 had reached 55%.
Twenty-three Police Forces in England and Wales participated in the study.
Forces were requested to submit samples confiscated from street-level users.
In early 2008, they submitted 2,921 samples for analysis to either the Forensic Science Service Ltd (FSS) or LGC Forensics at Culham (LGC F).
Initial laboratory examination showed that 80.8% were herbal cannabis and
15.3% were cannabis resin. The remaining 3.9% were either indeterminate or
not cannabis.
Microscopic examination of around two-thirds of the samples showed that over 97% of the herbal cannabis had been grown by intensive methods (sinsemilla).
The remainder was classed as traditional imported herbal cannabis.
Regional variations were found in the market share of herbal cannabis. Thus
North Wales, South Wales, Cleveland and Devon and Cornwall submitted
proportionately fewer herbal cannabis samples, whereas Essex, Metropolitan
and Avon and Somerset submitted proportionately more. These differences
were statistically significant at the 0.1% confidence interval.
The mean THC concentration (potency) of the sinsemilla samples was 16.2%
(range = 4.1 to 46%). The median potency was 15.0%, close to values reported by others in the past few years.
The mean THC concentration (potency) of the traditional imported herbal
cannabis samples was 8.4% (range = 0.3 to 22%); median = 9.0%. Only a very small number of samples were received and analysed.
The mean potency of cannabis resin was 5.9% (range = 1.3 to 27.8%). The
median = 5.0% was typical of values reported by others over many years.
Cannabis resin had a mean CBD content of 3.5% (range = 0.1 to 7.3%), but
the CBD content of herbal cannabis was less than 0.1% in nearly all cases.
There was a weak, but statistically-significant, correlation (r = 0.48; N = 112;
P < 0.001) between the THC and the CBD content of resin.
INTRODUCTION
Herbal cannabis and cannabis resin are the most widely-misused illicit substances in the UK. For many years, herbal cannabis was imported into the UK from the Caribbean, West Africa and Asia. It is often seen in the form of compressed brown vegetable matter containing seeds and stalks (Figure 1). Domestic production of intensively-cultivated herbal cannabis started in around 1990. It has been grown indoors from selected seed varieties and propagation of female plant cuttings using artificial lighting, heating, and control of day-length. This material is known as sinsemilla (without seeds; Figure 2). It consists mostly of the flowering tops of female plants, and is easily distinguished from the imported material. Cannabis resin (Figure 3) has been imported mostly from North Africa. The potency of cannabis is defined as the concentration (%) of Δ9-tetrahydrocannabinol (THC), the major active principle of the cannabis plant. Apart from THC, cannabis and cannabis resin contain many other so-called cannabinoids. One of these (cannabidiol, CBD) has attracted recent interest because it is believed to show anti-psychotic properties.
In 2006, the Advisory Council on the Misuse of Drugs (ACMD) reviewed the
classification of cannabis (Reference 1). One of the recommendations was that a further study should be carried out to determine the market share of different types of cannabis and their potencies. In view of current scientific interest in the role of CBD, it was decided that this should also be measured.
The Home Office funded the project. This included paying the forensic providers to establish the methodology using internal THC and CBD standards and to exchange samples for the comparison and harmonisation of the method for the determination of THC and CBD concentrations. The numbers of samples examined was then limited by the funds available.
In late 2007, police forces in England and Wales were invited to participate in a cannabis study. For administrative reasons, forces in Scotland and Northern Ireland were not involved. Police were requested to submit samples of cannabis confiscated from street-level users when issuing a warning and submit them to their usual service provider for laboratory examination. Samples from the Metropolitan Police were sent to both FSS and LGC Forensics. These samples were separate from those sent to laboratories for evidential purposes. There was no cost to the forces except the effort of administering the exercise.
On receipt at the laboratories, samples were weighed and visually examined by experts to determine if they were herbal cannabis, cannabis resin or something else (e.g. mixture, pipe, grinder, white powder). Also at this stage, many samples were identified as being too small for full analysis. A random selection of herbal cannabis samples was then submitted for more detailed microscopic examination to distinguish sinsemilla from traditional imported cannabis.
Herbal cannabis is an non-homogeneous product. The active constituents are
produced by secretions of glandular trichomes, most of which are situated on the bracts of the female flowers. For this reason, leaves and stalk contain little THC.
Although cannabis resin is more homogeneous, atmospheric oxidation of THC
causes the concentration of THC to be lower in the outer surface of a resin block than in the middle. Because the samples were small, it was agreed that the whole would be used for quantitative analysis to avoid errors caused by sample inhomogeneity.
Of the resin, sinsemilla and traditional imported samples, further random samples were examined to determine the THC and CBD content. The two laboratories used a similar analytical procedure that incorporated shared cannabis reference standards to ensure consistency. The homogenised samples were extracted with ethanol containing the internal standard androstenedione. The concentrations of total THC (THC and THC acid) and CBD were determined using either gas-chromatography or gas-chromatography coupled to mass-spectrometry with THC and CBD as external standards.
RESULTS
Twenty-three Police Forces in England and Wales participated in the study. In early 2008, they submitted 2,921 samples for analysis to either the Forensic Science Service Ltd (FSS) or LGC Forensics at Culham (LGC F).
The numbers of samples from each force should not be seen as a measure of the ‘cannabis problem’ in their area. For operational reasons some forces chose to send in material from only one Borough Command Unit or from one of several forces collection points. Some forces experienced internal logistics problems; others were very enthusiastic and sent in everything received during the trial period.
Initial laboratory examination showed that 80.8% were herbal cannabis and 15.3% were cannabis resin.
The remaining 3.9% were either indeterminate or not cannabis. The composition of samples for each police force is set out in Table 1; the two laboratories are shown as Lab 1 and Lab 2.
The weight of samples submitted was 4-5g, and typical of what might be termed street-level amounts.
Of the 2,352 samples of herbal cannabis, further examination of around two thirds of the samples showed that over 97% had been grown by intensive methods and were classified as sinsemilla. The remainder were classed as traditional imported herbal cannabis.
Regional variations were found in the market share of herbal cannabis. Thus North Wales, South Wales, Cleveland and Devon and Cornwall submitted proportionately fewer herbal cannabis samples, whereas Essex, Metropolitan and Avon and Somerset submitted proportionately more (Figure 4). These differences were statistically significant (Chi-squared test) at the 0.1% confidence interval. Figure 4 excludes those few samples that could not be classified as either herbal cannabis or cannabis resin on initial examination.
Following the second stage of analysis, where herbal cannabis samples were subdivided into those that were or were not sinsemilla, it was found that the proportion of sinsemilla was high in all force areas (Figure 5).
Figure 6 shows the distribution of the potency in the samples examined. The mean THC concentration in sinsemilla samples was 16.2% (range = 4.1 to 46); the median was 15.0%. The mean THC concentration in traditional imported herbal cannabis samples was 8.4% (range = 0.3 to 22%); median = 9.0%. The number of traditional imported herbal cannabis samples received and analysed was small. The mean potency of cannabis resin was 5.9% (range = 1.3 to 27.8), median = 5.0%.
Figure 7 shows the distribution of CBD in cannabis resin. The mean CBD content was 3.5% (range = 0.1 to 7.3), but the CBD content of herbal cannabis was less than 0.1% in nearly all cases.
Figure 8 shows all THC and CBD data plotted as a scatter diagram. There was a weak, but statistically- significant, correlation (r = 0.48; N = 112; P < 0.001) between the THC and the CBD content of resin.
It will be seen from Figure 8 that three samples of herbal cannabis had anomalously high CBD values. The reason for this is not understood.
For both sinsemilla and cannabis resin, small differences were found in the median potencies for samples examined by the two laboratories (Table 3). However, these may have arisen from differences in the potency of cannabis in different geographical areas, as reported by Potter et al. (Reference 3). The laboratories had harmonised their methods and exchanged test samples so the results were comparable.
The proportion of herbal cannabis has increased markedly in recent years. In 2002 it was estimated that it represented around 30% of police seizures of cannabis (Reference 2), but by 2004/5 (Reference 3) this had increased to 55%. In the present study, herbal cannabis accounted for over 80% of all cannabis seized by the police on the street when giving a warning. Furthermore, almost all of that material was sinsemilla. There has been a decline in the prevalence of cannabis resin, and traditional imported herbal cannabis is now rarely seen (Table 2). Some sinsemilla is imported from other European countries and some is domestically-produced.
This rise in the market share of herbal cannabis over the past six years has also been reported in samples submitted to the FSS (Reference 4) and LGC Forensics (Reference 5) for evidential purposes, although they may be less representative of what is available at street level.
The median potency of sinsemilla in this study (15.0%) was only marginally greater than the median value (13.98%) reported by Potter et al. (Reference 3) for samples collected in 2004/5. Since 1990, when intensively-grown cannabis first appeared in the UK its potency has slowly increased, but this appears to have stabilised. By contrast, the mean/median potency of cannabis resin and imported herbal cannabis has remained largely unchanged over many years (Reference 2). Although the potency of sinsemilla is, on average, 2-3 times that of imported herbal cannabis or cannabis resin, the various populations show considerable overlap (Figure 6).
See pdf document to continue reading HOME OFFICE CANNABIS POTENCY STUDY 2008
