Frontal lobe circulation in patients of schizophrenia with and without cannabis dependence: A comparative study

Abstract Background: The symptom profile of schizophrenia is related to the regional cerebral circulations as advocated in various studies. Cannabis dependence in schizophrenia is more common than in the general population. Previous studies comparing the frontal lobe function in schizophrenia with and without comorbid cannabis dependence have shown conflicting results. In this study, we compared the blood flow in the frontal lobes of patients of schizophrenia with and without comorbid cannabis dependence. Aim of the Study: The aim was to compare the blood flow in the anterior cerebral artery (ACA) and middle cerebral artery (MCA), in patients of schizophrenia with and without cannabis dependence. Materials and Methodology: This was a hospital-based cross-sectional study. After fulfilling the inclusion and exclusion criteria 28 patients of schizophrenia with cannabis dependence and 28 patients of schizophrenia without cannabis dependence were selected for the study. The blood flow was assessed using Trans-cranial Doppler (TCD) in the ACA and MCA of the left and right sides in both the study groups through the temporal window. Results: A statistically significant difference ( P = 0.049) was found in the pulsatility index of the left ACA where it was lower in schizophrenia patients with cannabis dependence (0.97 ± 0.24) in comparison to schizophrenia patients without co-morbid cannabis dependence (1.11 ± 0.28). However, after using Bonferroni correction for multiple comparisons ( P < 0.05/12 i.e., P < 0.004), this comparative statistics too lost its significance. No significant difference was found in the mean flow velocity and resistance index of frontal lobe circulation between the two groups. Conclusion: Chronic cannabis use is having some sparing effect on vascular resistance in the frontal circulation of schizophrenia patients. However, this effect is not significant enough to alter the pattern of frontal circulation.