This 1991 study aimed to investigate the developmental outcomes of 59 Jamaican children whose mothers heavily smoked cannabis during pregnancy. Challenging popular mainstream misconceptions, the study found there were no significant differences in developmental outcomes between children of heavy cannabis smokers and non-users, except at the critical 30-day mark. At this 30-day mark, infants from mothers who heavily smoked cannabis exhibited more favorable scores in autonomic stability and reflexes compared to infants of non-using mothers.
The study encourages critical thinking and prompts a reevaluation of the mainstream narrative that continues to perpetuate inaccurate information about the effects of maternal cannabis use on child development. The significance of this outcome lies in debunking the mainstream narrative and calling for a more nuanced understanding of the potential impacts of cannabis use during pregnancy.
The findings suggest that prenatal cannabis smoking did not adversely affect the children's development at any time tested, including birth, 1 day, 3 days, 30 days, 4 years, and 5 years of age.
The study originally enrolled a total of 60 women, with an equal distribution of 30 cannabis-users and 30 non-users, ranging in age from 16 to 38 years. To minimize the confounding effect of socioeconomic status, the participants were matched based on age, parity, and socioeconomic status, and were drawn exclusively from the rural lower income class. The sample excluded other risk factors that could influence developmental outcomes, such as polydrug use, alcohol consumption, tobacco smoking, and low birth weight.
When the children reached ages four and five, the study divided the sample into four groups based on the average amount of cannabis consumed per week. These groups were categorized as light users, moderate users, heavy users, and non-users.
Light cannabis users smoked up to 10 "marijuana cigars" or "spliffs" per week, while moderate users consumed between 11 and 20. However, it is the heavy user group that stands out, as they were consuming between 21 and 70 spliffs per week. This level of cannabis consumption suggests that some of these women were smoking cannabis all day, every day. In fact, smoking 70 joints per week is an impressive number even for the most seasoned cannabis smoker. Even the light cannabis user group who smoked up to 10 spliffs per week could be considered heavy users to many people.
It is important to acknowledge that the terminology used in the study may differ from contemporary understanding of cannabis slang. While the term "spliff" implies a mixture of cannabis and tobacco in the United States, it is reasonable to assume that the study refers to what we now recognize as a joint, with only cannabis. This assumption is supported by the fact that the study was conducted in Jamaica and was not confounded by the presence of other risk factors such as tobacco smoking.
Nevertheless, regardless of the specific terminology, the study's findings challenge prevailing mainstream assumptions. They demonstrate that even individuals engaged in heavy cannabis use, smoking cannabis throughout the day and every day, showed no discernible negative effects on child development.
While the specific type of cannabis used by the women in the study is not described, we can make certain assumptions based on the time period and location. Given that the study took place in the 1980s in a rural area in Jamaica, it is likely that the cannabis strains used were more wild and traditional variants, representing a more balanced composition of cannabinoids like THC and CBD, unlike the modern cannabis flowers today that are bred to have extremely high and unnatural levels of THC with no CBD and other cannabinoids.
The study employed a comprehensive approach to data collection, utilizing both direct observations and standardized questionnaires to gather information on the child's environment and temperament. The results revealed no significant differences in developmental testing outcomes between children of cannabis-using and non-using mothers, except for a notable finding at 30 days of age. At this stage, the infants of mothers who smoked cannabis during pregnancy demonstrated more favorable scores in two clusters of the Brazelton Scales: autonomic stability and reflexes.
The study utilized two assessment tools to evaluate the development and abilities of young children. The Brazelton Scales and the McCarthy Scales of Children's Abilities (MSCA) were employed for this purpose. The Brazelton Scales, specifically the Brazelton Neonatal Behavioral Assessment Scales, were utilized to assess the behavior and functioning of infants at 1, 3, and 30 days of age. This assessment tool focuses on various aspects of newborn behavior, including reflexes, motor skills, and social responsiveness. On the other hand, the McCarthy Scales of Children's Abilities were used to measure cognitive abilities in six different domains: verbal, perceptual-performance, quantitative, general cognitive, memory, and motor. These scales were administered when the children reached the ages of four and five years, providing an assessment of their cognitive capabilities during early childhood. By utilizing these assessment instruments at different stages of development, the study aimed to gather comprehensive information about the children's behavioral and cognitive progress from infancy to early childhood.
The study found correlations between the developmental scores at ages four and five and specific aspects of the home environment, as well as regular attendance at basic school. This highlights the importance of the child's surroundings and educational experiences in shaping their developmental outcomes. The authors concluded that factors such as a stimulating home environment, encouraging mature behavior, and consistent school attendance emerged as influential factors in predicting higher developmental scores on the assessments, and not the mother's cannabis use.
The authors' emphasis on the powerful influence of environmental factors in explaining the lack of negative findings related to heavy prenatal cannabis exposure raises questions about the significance of cannabis use. By suggesting that these factors may overshadow any potential effects of cannabis, the authors challenge the prevailing belief that cannabis is a major concern. These findings imply that cannabis may not have the detrimental impact often portrayed, suggesting that the fear surrounding it could be largely based on propaganda rather than solid scientific evidence.
However, a critical examination of the studies interpretation reveals potential biases and a reluctance to acknowledge the possibility that heavy cannabis use could contribute to these results.
The authors' way of looking at the results when they found no harmful effects from using cannabis during pregnancy is concerning and deserves criticism. The authors of the study appear reluctant to acknowledge the remarkable findings that heavy cannabis use has no discernible effects on babies during pregnancy and even up to five years after birth. Instead, they seem inclined to downplay these findings by attributing them to other variables such as the child's environment and school attendance. However, it is important to consider the possibility that heavy cannabis use itself may have either no significant impact on developmental outcomes or even potentially a positive impact, as suggested in this study and other studies on this topic.
By shifting the focus away from the cannabis use variable, the authors miss an opportunity to discuss the implications of their findings, which challenge prevailing beliefs about the risks of prenatal cannabis exposure. It is crucial to recognize the importance of these findings, as they provide valuable insights that can potentially debunk stereotypes and misconceptions surrounding cannabis use during before, during, and after pregnancy.