The goal set by the research of Guzel et al was to discover the adverse effects of chronic synthetic cannabinoid use on hematologic cells. There has been extensive research in the last 20 years on cannabinoid use and its effects on numerous physiology and psychology health issues. However, according to the authors, there has been little research performed on the effects of synthetic cannabinoids on physical and mental health, and to their knowledge, none on hematologic cells. Synthetic cannabinoids are designer drugs that mimic cannabis’ psychoactive effects and were marketed as legal alternatives to cannabis in Europe in the early 2000s. In Turkey, where there is a wide prevalence of synthetic cannabinoid users, the chemicals are manufactured by unreliable laboratories, mixed with acetone as a method to spray or soak onto dried plant materials, and produced in hundreds of different chemical forms with names such as Spice, Bonsai, K2, etc.
Guzel et al performed the study on 40 healthy volunteer people (control group) and on 40 chronic users of synthetic cannabinoids (study group) who were patients of Sakarya University Education and Research Hospital Alcohol and Substance Treatment and Education Center inpatient clinic admitted between October 2014 through June 2016. The study patients had to meet the criteria of having used synthetic cannabinoids for more than one year, tested positive for cannabinoids in urine, and with no polysubstance use disorder or other comorbid organic disorder. Blood was taken from both groups on the first day of admission and tested for a red blood cell count (RBC) with indices (MCH, MCV, MCHC, RDW), a white blood cell count (WBC) expressed as a percentage and relative count, platelet count with mean platelet volume (MPV), serum iron, total iron-binding capacity (TIBC), and unsaturated iron-binding capacity (UIBC). The test values from the study group were all within normal parameters, however, they showed a statistically significant difference (p<0.05) between the control group in terms of the MCH, RDW, MCV, MPV, WBC, neutrophils, % lymphocytes, % monocytes, TIBC, IUBC, and neutrophil to lymphocyte ratio (NLR). In the abstract of the research article Guzel et al stated, "Our data suggested that chronic use of cannabinoids can lead to deterioration of hematopoietic cells. Chronic use of cannabinoids was consistent with subthreshold/subclinical megaloblastic anemia with iron deficiency." However, in the discussion, Guzel et al suggested that synthetic cannabinoid use can provoke an immunologic reaction (not suppression) due to the increase in white blood cell count as seen in the neutrophils and monocytes. And although the red blood cell count showed a statistically significant decrease in the red blood cell indices MCH, RDW, and MCV in the study group, all the red cell blood cell values were within normal ranges (not anemic). According to Snow (1999), megaloblastic anemia is defined as a macrocytosis (MCV >100) with or without anemia and is the physiologic result from either a vitamin B12 or folate deficiency (Snow, 1999). The study group did not meet the MCV criteria for megaloblastic anemia, nor were the patients tested for vitamin B12 and folate. However, decreased iron levels were exhibited by the study group and with a TIBC and UIBC higher than that of the control group. The reason for this, proposed by Guzel, is that substance abusers are known to have nutritional problems due to poor dietary habits.
The research performed by Guzel et al does show a statistical significance between the study group consisting of chronic synthetic cannabinoid users and the control group in several of the blood test parameters and as stated in the conclusion section they believe “this study presents a relationship between synthetic cannabinoids and hematologic parameters.” However, as noted by Guzel et al this a “frontier study” and “further studies, with a larger sample size and long-term follow up, are needed to confirm and explain these results.”