Introduction

Cannabis is the most commonly used illicit drug worldwide despite evidence suggesting a number of harmful effects (Caspi, 2005). It has attracted copious amounts of media attention regarding the possible long-term effects of smoking cannabis, as it has been suggested it can mediate a number of mental health issues, ranging from psychotic symptoms such as hallucinations (visual and auditory) and to the chronic clinical disorder, Schizophrenia.
There has been great discrepancy about the harmful effects of cannabis use, reflected in the constant debate about whether it should be classified as a class B or class C in the 1971 Misuse of Drugs Act (Mcleod, 2010) whereas some even believe it should be legalized. Legalizing cannabis has caused uproar within in social and even scientific settings because some believe its use provokes Schizophrenia, however, there a large number of users who never develop this psychotic illness. Schizophrenia is a serious mental illness characterised by delusions (loss of contact with reality) and hallucinations (visual and auditory) i.e. perceiving stimuli which aren’t present. Schizophrenia has a global prevalence of 1.5%, although, it is unclear what percentage of this is caused by cannabis use. It is huge financial public health issue in both human and material aspects (Murray, 2003) and although it has been reported for many years, ts aetiology is still poorly understood This article aims to evaluate recent evidence concerning this issue to establish whether it should be classified and if so, at what level is reflective of harmful effects.

Cannabis

There are two active constituents of cannabis, the psychoactive constituent of cannabis is 9-delta-tetrahydrocannibol (THC) and cannabidiol. THC mediates its euphoric effects via CB1 receptors (a subtype of cannabinoid receptors found in the brain and various peripheral