How Is Marijuana Dependence Linked to Mental Disorders?
Cannabis is the umbrella term for the mind-altering products marijuana, hashish and hashish oil, which come from the cannabis group of plant species. All of these products create substantial risks for physical dependence and addiction when used regularly for relatively extended amounts of time. Cannabis use also comes with a known risk for psychosis and certain other mental health problems. In a study published in August 2013 in the journal Addiction, a team of Dutch researchers looked at the relative risks for mental illness in dependent/addicted marijuana users and users unaffected by dependence/addiction. The researchers concluded that the mental illness risks in these populations differ in substantial ways.
What Exactly Is Cannabis?
Marijuana comes from dried, non-concentrated parts of Cannabis plants such as the leaves, stems and flowers. Hashish and hashish oil, on the other hand, come from the purposeful concentration of these plant parts. All three of these cannabis-based products contain the same active ingredient, known informally as THC and formally as tetrahydrocannabinol. THC triggers changes in brain function that create the classic effects of cannabis intoxication, including altered thinking and sensory perception, a rise in pleasurable feelings, appetite increases, reduced clarity in several major areas of consciousness, and a reduced ability to move the body’s muscles in an efficient, controlled manner.
Marijuana’s Dependence And Addiction
Despite its reputation as a relatively harmless, “natural” substance, THC can make substantial alterations in a person’s long-term brain function when used repeatedly or habitually over time. These changes in function can eventually make the brain “see” the presence of THC as a chemical norm rather than a rare or occasional event. When this situation arises, the affected individual has what’s known as a physical dependence on the effects of cannabis/THC. By itself, physical dependence on a substance does not necessarily constitute a dangerous or harmful situation. However, when combined with persistent drug-seeking behaviors and other disruptive or dysfunctional actions, dependence establishes the necessary groundwork for the onset of a drug addiction.
Mental Health Risks Of Marijuana Use
While under the temporary influence of cannabis products, users commonly experience short-term symptoms that closely approximate psychosis, an altered mental state (classically associated with schizophrenia and schizophrenia-related illnesses) that primarily features delusional thought processes and/or some sort of sensory hallucination. In some cases, regular users develop a more extended form of psychosis that continues as long as a pattern of cannabis intake continues. In addition, current evidence strongly indicates that habitual cannabis users have increased long-term chances of developing diagnosable cases of schizophrenia or depression that continue to exert their effects even when a pattern of cannabis intake stops.
In the study published in Addiction, researchers from the University of Amsterdam and the Netherlands Institute of Mental Health and Addiction sought to determine if people physically dependent on cannabis have higher risks for developing mental health issues than cannabis users unaffected by dependence. They made this determination by tracking the mental health diagnoses of 252 young adults affected by cannabis dependence, as well as the diagnoses of 269 young adult, non-dependent cannabis users. For comparison’s sake, they also tracked the mental health diagnoses of over 1,000 non-cannabis-using young adults. The researchers did not attempt to differentiate issues of cannabis dependence from issues of cannabis addiction.
Effects On Mental Illness In Dependent vs. Non-Dependent Marijuana Users
After reviewing the gathered data, the researchers found that both dependent and non-dependent cannabis users have a higher rate of mental illness than people who don’t use cannabis at all. They also found that dependent and non-dependent cannabis users are similar in most ways and share comparable patterns of general cannabis use, patterns of other forms of substance use and histories of problematic or traumatic childhoods. While dependent cannabis users have a higher overall rate of mental illness than non-dependent users, non-dependent users have higher rates than dependent users for illnesses called externalizing disorders, which include attention-deficit/hyperactivity disorder (ADHD), oppositional defiant disorder and conduct disorder. Conversely, dependent users have particularly high rates for illnesses called internalizing disorders, which include mood disorders (depressive and bipolar illness) and a range of conditions referred to together as anxiety disorders.
Most of the difference in the mental illness rates between dependent and non-dependent cannabis users disappeared when the authors of the study published in Addiction took certain secondary factors into account, including the use of other substances and the presence of traumatic or problematic childhoods. However, even with these adjustments, dependent users still have higher illness rates than non-dependent users. Except for the spike in their rates for ADHD, oppositional defiant disorder and conduct disorder, non-dependent cannabis users have mental health profiles that closely resemble the profiles found among people who don’t use cannabis.