Health and Psychological Effects of the Use of Marijuana. Research review

 Marijuana and Memory Impairment

Short-term memory loss is one of the most common problems that is self-reported by the users and is one of the major cause people seek to quit or reduce the use of marijuana Belmore et. Al. (1980). Hippocampus is the major anatomically related structure that is essential for memory functions. Chronic drug abuse like marijuana may have detrimental effects on hippocampus functions which may lead to impaired memory performance. Numerous studies have been done to report the relationship between memory function and marijuana abuse but many of them have focused only on impaired immediate and delayed free recall of information while some others have focused in manipulating, storage, processing and organization to optimize episodic memory encoding and impaired retrieval performance. But very less number of studies has been done focusing the relationship between memory, structural changes in brain and marijuana abuse which can increase the validity and reliability of the tests.

Most recent report presented by Ashtari et al. (2011) have included the structural changes in brain and have reported bilateral hippocampus atrophy association with memory loss following long-term use of marijuana. This study may be the most valid and reliable recent report in the study of a relationship between marijuana and memory impairment as the authors have used fourteen treatment-seeking male adolescents (mean age = 19.3) who reported a mean age of first-time marijuana use of 13.1 years with an average minimum use of 5.8 joints per day. This study was carried out after the users were drug-free for an average duration of 6.7 months and the study has used Magnetic Resonance Imaging (MRI) study, Image processing techniques of the brain and neurocognitive evaluation techniques as California Verbal Learning and Memory Tests. Although this study has some limitations as small sample size; dose, frequency, onset and length of use of marijuana are validated based on self-report and the effects of alcohol and tobacco are neglected, this study has used various latest technologies and methods and have maintained 6.7 months average period of abstinence from the drug to validate the long-term effects of marijuana use. However, some recent studies done by Jager et al (2010) and Tzilos et al (20050 have shown normal hippocampus activity and structure following marijuana use but they have used either too younger or older subjects in the study with a short period of marijuana use which has reduced the validity of the tests.

Conclusion

Although several studies have concluded their studies against the serious disabling psychological effects of marijuana abuse, most of the recent studies have shown clear evidence of possible adverse effects on various cognitive functions of human which may affect directly on the individuals’ work performances and daily activities. Marijuana may have some of the serious detrimental psychological effects and in some cases, it may exacerbate the psychological symptoms in those who already have some of the psychological disorder symptoms like schizophrenia, anxiety, depression and personality disorders. So, use of marijuana is a high-risk factor for those who already persist with some psychological problems than the normal individuals. Social environment factors such as social fear, anxiety, and stress have greater influence in pushing many people towards marijuana abuse and also a resultant increment in its related problems. Many of the studies have a common view on a higher degree of psychological effects on the individuals with early onset of use of marijuana than later onset users. However, more studies are mandatory to determine the particular age, dose, frequency and duration of marijuana use which can cause serious psychological effects in the users.

Cognitive dysfunctions are the most common psychological problem due to the chronic long term use of marijuana in all age group of people. Recent studies have also presented serious alteration in the structure and functional activity of certain regions of the brain which are mainly responsible for the control of cognitive functions such as hippocampus size and activity. These studies also suggest that early onset of marijuana abuse can lead to serious developmental disorder in the medial temporal structures and possibly cause chronic disruption of hippocampus functions.

So, there is a number of research on the psychological effects of marijuana but many of them have various limitations, for example, a small number of subjects, a lesser time period of marijuana use, lesser period of the gap from drug abuse to study post drug use long term effects etc. There is a need for more valid and reliable study covering all the parameters of marijuana use and determine the specific dose, frequency, duration and age of people which can have serious adverse health and psychological effects. Although some studies have strong evidence on no direct psychological effects of marijuana, they have recommended not using marijuana unless it is for some proven medicinal purposes and that the very early onset and long-term use can cause serious psychological problems.

Reference