This article aims to show that ADHD in combination with chronic cannabis abuse does substantially increase the risk of developing schizophrenia and other disorders.
I'm not a neuro-biologist. This article doesn't mean to add any scientific value. Please do not cite anything or take its plausibility/correctness for granted. This is just a hobby and part of therapy in terms of fun activity.
Abstract
Due to their impulsive behaviour, a lot of people with ADHD tend to misuse substances like cannabis --- Does chronic cannabis consume and ADHD affect the risk of developing psychotic disorders, such as schizophrenia? --- A small meta-analysis.
Increased Risk of Developing Drug-Induced Psychotic Disorders in Patients with ADHD
Preface
With over 24 million users, cannabis is the most widely used drug in the USA; a seemingly harmless substance if you smoke a joint in the morning - abuse, however should not be underestimated as it may have long term consequences.
ADHD
ADHD often correlates with substance abuse.[[^adhd-substance-misuse]] People who suffer from ADHD should be extra cautious dealing with drugs. Increased risk of addiction[[^adhd-substance-misuse-2]] and high prevalance[[^adhd-prevalance]] of comorbid disorders carry a high risk of developing psychotic and personality disorders.
Adolescents with attention-deficit/hyperactivity disorder (ADHD) are known to be at significantly greater risk for the development of substance use disorders (SUD) compared to peers. Impulsivity, which could lead to higher levels of drug use, is a known symptom of ADHD and likely accounts, in part, for this relationship. -- Childhood ADHD and Risk for Substance Dependence in Adulthood: A Longitudinal, Population-Based Study
To examine the 12-month prevalence, risk factors, and comorbidity of ADHD in a collective of adult psychiatric patients admitted to an open general ward in a psychiatric hospital in Schleswig-Holstein (Germany) over a period of one year
The 12-month prevalence of ADHD was 59.0 % (severe symptomatology: 33.1 %), high rates of comorbid disorders (92.9 % depression, 5.1 % bipolar disorder, 28.6 % anxiety disorder, 30.6 % emotional unstable (Borderline) personality disorder, 31.6 % avoidant personality disorder, 18.4 % dependent personality disorder, 25.5 % combined personality disorder, 10.2 % obsessive-compulsive personality disorder, 26.5 % PTSD, 25.5 % restless legs syndrome, 24.5 % adiposity, 11.2 % eating disorder, 45.9 % learning difficulty, 51.0 % ni cotine dependency, 4.1 % alcohol dependency, 7.1 % illegal substance dependency), risk factors for ADHD, a high genetic risk (72.4 %) and problems in psychosocial functioning. -- Attention-deficit/hyperactivity disorder (ADHD) in adult psychiatry: Data on 12-month prevalence, risk factors and comorbidity
Psychosis
Frequent long-term abuse of potent cannabis can cause psychotic symptoms and increase the risk of psychotic disorders such as schizophrenia or schizoaffective. [[^cannabis-psychosis-risk-factor], [^cannabis-schizo-evidence], [^cannabis-schizo-risk-value]]
Cannabis is a known risk factor for schizophrenia, although the exact neurobiological process through which the effects on psychosis occur is not well-understood.
Cannabis is involved in approximately 50% of psychosis, schizophrenia, and schizophreniform psychosis cases.[1,2,3,4,5] -- Cannabis and psychosis: Neurobiology
Conclusion.
Long term cannabis use favors the development of psychotic disorders such as schizophrenia[[^cannabis-psychosis-risk-factor], [^cannabis-schizo-evidence], [^cannabis-schizo-risk-value]], as it directly stimulates the mesolimbic system[[^cannabis-effects-thc]], which leads to a constant excess of dopamine[[^cannabis-dopamine]]. Given their general affinity to psychotic disorder development[[^adhd-prevalance]] and the combination of the underlying dopamine deficiency[[^adhd-sugar]] in persons with ADHD[[^adhd-dopa]], this leads to a much higher risk of developing drug-induced psychoses such as schizophrenia due to chronic imbalance of dopamine levels between the reward system and the prefrontal cortex. --- A condition the dopamine hypothesis postulates.[[^schizo-role-dopamine]]
Cannabis use doubles the risk of developing psychosis in vulnerable people. There even exists a relationship regarding the dose used and the age of first use. -- Cannabis consumption and psychosis or schizophrenia development
In vivo microdialysis shows that acute THC increases dopamine efflux in the prefrontal cortex (PFC) 41, striatum 42 and nucleus accumbens -- The effects of Δ9-tetrahydrocannabinol on the dopamine system
Increases in mesolimbic dopamine transmission are observed when animals are treated with all known drugs of abuse, including cannabis -- A Brain on Cannabinoids: The Role of Dopamine Release in Reward Seeking
The revised dopamine hypothesis states that dopamine abnormalities in the mesolimbic and prefrontal brain regions exist in schizophrenia.
DA hypothesis proposed that the positive symptoms of schizophrenia are due to an excess of DA signaling in the striatal and/or mesolimbic areas of the brain3. In contrast, negative symptoms are thought to be related to deficits in prefrontal cortical DA signaling, likely through D1receptors4,5 -- The Role of Dopamine in Schizophrenia from a Neurobiological and Evolutionary Perspective: Old Fashioned, but Still in Vogue
Dysfunction of dopaminergic system is implicated in many neuropsychological diseases, including attention deficit hyperactivity disorder (ADHD) -- Role of dopamine receptors in ADHD: a systematic meta-analysis
The observation that ADHD represents a dopamine-deficient state could explain why treatments that increase dopamine levels in the nucleus accumbens, such as amphetamine and methylphenidate, improve symptoms, at least acutely.3 However, based on the increasing evidence for D2 receptor desensitization/downregulation as a mechanism underlying ADHD, one might expect these drugs to have an enhanced potential to cause addiction -- Attention-Deficit/Hyperactivity Disorder: Is it Time to Reappraise the Role of Sugar Consumption?
[^adhd-substance-misuse]:Long-Term Outcomes of Attention-Deficit/Hyperactivity Disorder and Conduct Disorder: A Systematic Review and Meta-Analysis PMID: 27663939 [^adhd-substance-misuse-2]:Childhood ADHD and Risk for Substance Dependence in Adulthood: A Longitudinal, Population-Based Study PMID: 25162629 | PMCID: PMC4146503 [^adhd-dopamine]: Attention-deficit-hyperactivity disorder and reward deficiency syndrome - PMID: 19183781 | PMCID: PMC2626918 [^adhd-prevalance]:Attention-deficit/hyperactivity disorder (ADHD) in adult psychiatry: Data on 12-month prevalence, risk factors and comorbidity PMID: 29490380
[^adhd-dopa]:Role of dopamine receptors in ADHD: a systematic meta-analysis [^adhd-sugar]:Attention-Deficit/Hyperactivity Disorder: Is it Time to Reappraise the Role of Sugar Consumption?
[^cannabis-psychosis-risk-factor]: Cannabis use and the risk of developing a psychotic disorder PMID: 18560513 | PMCID: PMC2424288 [^cannabis-schizo-evidence]: Cannabis and psychosis: Neurobiology PMID:29490380 [^cannabis-schizo-risk-value]:Cannabis consumption and psychosis or schizophrenia development PMID:30442059
[^cannabis-effects-thc]:The effects of Δ9-tetrahydrocannabinol on the dopamine system [^cannabis-dopamine]:A Brain on Cannabinoids: The Role of Dopamine Release in Reward Seeking [^schizo-role-dopamine]:The Role of Dopamine in Schizophrenia from a Neurobiological and Evolutionary Perspective: Old Fashioned, but Still in Vogue
dedicated to Mr. Schremel