The impact of Nyaope use on brain metabolic function

Introduction: Nyaope is a highly addictive cocktail street drug commonly found in South Africa. It consists of a host of substances such as opiates, benzodiazepines, low grade heroin, cannabis products, antiretroviral drugs and other materials added as cutting agents. Users tend to present with features suggestive of central nervous system effects such as notable self-neglect, slow slurred speech, slow movements, lethargy, poor judgement and a generally dazed expression.

Although limited, studies suggest that nyaope use has direct negative impact on body organs and systems, the behavior of the users suggests a central nervous impact. Functional neuroimaging studies have shown an association between various drugs and brain metabolism but we are not aware of any studies that specifically focus on the impact of nyaope. The aim of study is to present the preliminary findings examining the association between Nyaope use and the metabolic changes in the brain using Flourine-18 Flourodeoxyglucose (F-18 FDG) Positron Emission Tomography (PET) scan.

Methods: Male participants with more than 4 years of using nyaope underwent a F18 FDG PET/CT brain scan at Nuclear Medicine Department in Dr George Mukhari Academic Hospital (DGMAH). Using the MIMneuro quantitative analysis solution, the patient's PET scans were compared to a library of 43 FDG Neuro Normals (19 females, 24 males) ranging from 41 to 80 years old. The Z-Score Analysis was used to display regions with low metabolism which we defined as regions with z-scores below -2, when normalized to whole brain. The statistical data analysis was conducted in R Statistical computing software of the R Core Team, 2020, version 3.6.3. Discriptive and inferential statistics were compiled. Correlation analysis was also applied to determine the association between different numerical measurements. Likert plots were used for handling multidimensional presentation of the categorical data.

Results: A total of 18 male chronic nyaope users with a mean age of 32.78±4.31 were included in the study. The duration of nyaope use ranged from 11 to 19 years, median of 14,5. The most common route of administration of the drug was through smoking. The F-18 FDG scans of the participants demonstrated a great predilecton for the parietal lobe causing decreased hypometabolism in the precuneus in the majority of the participants, and predominantly on the right side (50% vs 38% on the left). There was also sinificantly decreased metabolism involving various regions of the occipital lobe, the amygdala and hippocampus. The temporal lobe was affected to a lesser degree while the frontal lobe appeared generally intact in all but 1 participant who was noted to have extensive and more widespread decreased brain metabolism which also involved the midstructures such as the basal ganglia. Although not statistically significant, when correlation was done between the duration of nyaope use and the decrease in metabolism in the precuneus, a tendency towards a negative correlation (--0.261) was noted, suggesting that participants who had been taking nyaope for longer periods may experience a more severe decrease in metabolism.

Conclusions: Our preliminary results indicate that Nyope use may cause far more extensive hypometabolism in the brain compared to other drugs of abuse that have been studied. Unlike in the majority of studies, the parietal and occipital lobe showed more extensive fallout compared to the other lobes. However nyaope is also noted to affect the limbic system and cerebellum as has been reported in people using opiods and cannabis substances. These findings demonstrate the potentially destructive nature of nyaope on brain function and there is an impression that the more prolonged its use, the tendency toward more extensive involvement. Larger studies are recommended to further validate these findings.