Single Effects of Marijuana and Psychosis

Essay by HaydencoxUniversity, Bachelor'sA, August 2011

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Topic 1: Brain Behaviour Relationship � PAGE �4�


Brain Behaviour Relationship: Marijuana and Psychosis

Marijuana, often referred to as Cannabis in the majority of the research material is a plant that contains psychoactive chemicals. The major psychoactive chemical compound is Δ9-tetrahydrocannabinol abbreviated to THC (Raymon & Walls, 2007). American Psychiatric Association (DSM-IV-TR) states that psychosis or a psychotic episode is an altered state of mind where the individual has difficulty distinguishing between delusional thoughts and reality (2000). Some symptoms that an individual may experience are hallucinations, paranoid delusions and disorganized speech (DSM-IV-TR). This essay aims to observe the link between Marijuana and psychosis and the related risk and protective factors.

Many epidemiological studies have researched the correlation between Marijuana and psychotic illness. The majority of which reported that using Marijuana is associated with the increased risk of psychosis (Fergusson, Poulton, Smith & Boden, 2006).

One study in particular found that the rates of Marijuana use is twice as likely among patients with psychotic symptoms than among controls (McCreadie, 2002, as cited in Arsenault, Cannon, Witton & Murray, 2004). This presents a link between people who suffer from psychotic illnesses are marijuana users.

Neuroscientific studies look at what the chemical Δ9-tetrahydrocannabinol found in marijuana has on the brain. THC affects the dopamine system, which is believed to play a key role in the development of psychotic symptoms (Fergusson et al. 2006). D'Sousa et al. (2005) found that the psychotic symptoms are partly caused by an increase in dopamine neurotransmission. This neurobiological evidence although limiting presents another correlation between a single use of marijuana leading to psychosic symptoms.

In a laboratory study conducted by Georgotas & Zeidenberg, (1979) as cited in Hall, Solowij & Lemon. (1994) found that participants with no prior psychotic illness showed...