from: http://www.psychiatrictimes.com/schizophrenia/schizophrenia-neurocognitive-dysfunction-and-substance-related-disorders-review Schizophrenia, Neurocognitive Dysfunction, and Substance-Related Disorders: A Review October 14, 2013 | Schizophrenia, Addiction, Neuropsychiatry, Substance Use Disorder By Maryam Sharif-Razi, Rachel A. Rabin, MSc, and Tony P. George, MD, FRCPC Linked Articles Medical Marijuana: Regulations Surrounding Its Use The Cannabis-Psychosis Link: Mind Your Mind Schizophrenia, Neurocognitive Dysfunction, and Substance-Related Disorders: A Review The Cannabis-Psychosis Link Mini-quiz: Schizophrenia and Cannabis Use Disorder Effects of nicotine on neurocognition among individuals with schizophreniaTable 1 Effects of cannabis on neurocognition among individuals with schizophreniaTable 2 Schizophrenia affects approximately 1% of the general population. It is characterized by positive symptoms, such as delusions, hallucinations, and disorganized speech, and negative symptoms, including blunted affect, reduced motivation, and poor social relationships.1 In addition, studies have consistently identified neurocognitive deficits as clinically relevant core features that affect 75% to 85% of schizophrenia patients and that may serve as critical indices of social functioning, treatment strategies, and functional outcomes.2 Neurocognitive dysfunction is observed across several domains, including working memory, attention, executive function, response inhibition, and processing speed.3 Approximately 50% of patients with schizophrenia will have a comorbid lifetime substance use disorder.4 Tobacco and cannabis are the most commonly used substances among these patients.5 The presence of a substance use disorder has been associated with alterations in neurocognitive performance.5,6 While previous studies have found positive effects of nicotine and tobacco smoking on neurocognition in schizophrenia, the effects of cannabis on neurocognitive function in schizophrenia are inconsistent and inconclusive.7,8 The aim of this article is to evaluate the effects of nicotine and cannabis on neurocognitive function in individuals with schizophrenia and to review potential pharmacological treatment strategies. Nicotine and tobacco Persons with schizophrenia are more likely to smoke cigarettes and to begin smoking at a younger age, extract more nicotine from each cigarette, have a preference for higher-tar cigarettes, and have reduced smoking cessation rates.9 Hypotheses have been proposed to explain comorbid smoking behaviors in these patients. The self-medication hypothesis suggests that schizophrenia patients smoke, in part, to alleviate negative symptoms, dysphoric mood, and neurocognitive impairments by ameliorating a dysfunctional dopamine system.10 The addiction vulnerability hypothesis suggests that genetic and neurobiological factors associated with schizophrenia (ie, alterations in nicotinic acetylcholine receptors [nAChRs] and central dopamine systems) may predispose schizophrenia patients to nicotine addiction.11 Examining the effects of tobacco smoking on neurocognition in schizophrenia is crucial because it may help clarify the rationale for high consumption of tobacco products and inform treatment interventions. Table 1 summarizes the significant findings on the effects of nicotine on neurocognition in persons with schizophrenia. A recent cross-sectional study by Wing and colleagues6 found smoking history and current smoking status to be associated with neurocognition in schizophrenia. Patients without any history of tobacco smoking performed worse than former and current smokers with schizophrenia on neurocognitive tasks that assess processing speed, attention, and response inhibition. A study of the effects of prolonged (up to 10 weeks) smoking abstinence on visuospatial working memory in patients with schizophrenia and controls found that the patients had impaired visuospatial working memory.12 Subsequently, a study by Sacco and colleagues7 examined visuospatial working memory under conditions of overnight smoking abstinence. They found that smoking abstinence specifically impaired visuospatial working memory in schizophrenia patients but not in controls. Abstinence-induced neurocognitive deficits were restored following restart of smoking. The effects of restarting smoking were blocked by treatment with the nAChR antagonist mecamylamine, which suggests that these pro-neurocognitive effects were dependent on nAChR stimulation. On the basis of these studies, there is consensus that cigarette smoking may transiently enhance visuospatial working memory and attention in schizophrenia. Whether these pro-neurocognitive effects extend to other domains has not been studied extensively in the literature. While a few studies of cigarette smoking in patients with schizophrenia have found positive effects on tasks that involve sensory gating, motor speed, processing speed, working memory, and executive function, other studies have demonstrated no significant differences in neurocognitive performance apart from modest improvements on attentional and spatial processing tasks.6,13-15 Interestingly, the studies that reported modest effects used brief, general neurocognitive batteries, which are not as sensitive as more comprehensive batteries.14,15 Comparative analyses across studies may be difficult to interpret because of methodological differences. For instance, while some studies have participants abstain from smoking for 2 hours, other studies have participants refrain from smoking overnight or for up to 7 days.15 This may create discrepancies among samples because individuals with schizophrenia who can maintain abstinence for 7 days may represent a less neurocognitively vulnerable subgroup of patients, even more so than patients who are able to refrain from smoking for shorter periods, also hypothesized to be inherently less susceptible to neurocognitive deficits.6 Furthermore, several studies do not provide comprehensive information concerning confounders and use small samples, lack control groups, and employ cross-sectional designs without consideration of longitudinal outcomes. These limitations should be addressed in future studies to provide a more uniform picture about the effects of tobacco use and neurocognitive function in schizophrenia. Cannabis (marijuana) Epidemiological studies indicate high rates of cannabis use disorders among individuals with schizophrenia, with lifetime prevalence of 13% to 64%.16 Evidence from longitudinal studies shows an increased risk of schizophrenia and psychotic symptoms following heavy cannabis use.17 Previous studies have proposed self-medication with cannabis to remedy symptoms of schizophrenia.18 In contrast to these studies, recent data show that cannabis misuse often occurs before the onset of psychosis and that psychotic and affective symptoms worsen after cannabis use.19 Table 2 summarizes the significant findings on the effects of cannabis on neurocognition in persons with schizophrenia. Surprisingly, schizophrenia patients with a comorbid cannabis use disorder demonstrate superior neurocognitive performance compared with non–drug-using patients.20,21 This may be counterintuitive given that cannabis use among nonpsychiatric controls has been consistently shown to have a deteriorating effect on neurocognitive performance and has been associated with poorer prognosis among schizophrenia patients.22-24 Given that neurocognitive dysfunction is a core feature in patients with schizophrenia and the high rates of cannabis use in these patients, a closer look at the association between cannabis use and neurocognition is warranted.

Thank you @Mouse. This is an important article. If you don’t mind, I would like to add a quote taken from the conclusion: “The general consensus on the effects of nicotine on neurocognition in schizophrenia seems to be that nicotine transiently improves spatial working memory and sustained attention.” Curiously, the earlier statement in the body of the article specifically says these effects are due to “cigarette smoking” and does not mention nicotine specifically. It is a difference worth noting, at least in my view. FWIW. Thanks again for sharing this with us.

There already are few threads about positive sides of nicotine. By the way - here you can find an article from Discover Magazine about nicotine: https://dl.dropboxusercontent.com/u/63697/C/TheNicotineFix\\_Discover\\_Magazine\\_March2014.pdf

I noticed that, too, @fredhanna My experience with ecigs using nicotine-alone ‘juice’ compared to whole-tobacco juice lead me to believe the author does not seem to understand or at least acknowledge that there are other active components of tobacco smoke. Cigarettes do deliver a large dose of these though, as does pipe smoke if inhaled.

I know of a schizophrenic who tried to quit smoking for his health and ended up having a psychotic break within a few days. Nicotine definitely keeps your nuts and bolts nice and tight. If I’m feeling stupidly/needlessly melancholy sometimes just some nicotine alone will push me out of it.

i believe that any addiction can lead to some kind of schizophrenia, schizophrenia doesn’t need a substance to get start, needs only a reason to arise. Psychological addiction lead to destabilisation of the logic and that can bring easy schizophrenia . Just my humble opinion

i believe that any addiction can lead to some kind of schizophrenia, schizophrenia doesn’t need a substance to get start, needs only a reason to arise.

Actually, researchers found out that nicotine helps people handle schizophrenia and increases their memory and attention; not that nicotine leads to schizophrenia…

@Viertel also in some cases they use LSD for healing of schizophrenia, but in high doses LSD lead to schizophrenia. that kind of iterations need highly professional observation and specific dosage for maximum results. Heedles usage most of the times bring reverse. In any way nicotine is a strange substance… Veryyyyyyyyy addicted, my God!!!

Nicotine may help but withdrawal from it certainly does not.

been reading through some tobacco history items and liked this one for brevity http://archaeology.about.com/od/tterms/qt/Tobacco-History.htm “Tobacco in the form of a potent type of Nicotiana rustica is always present in their traditional medical practices, and it is used for purification, to cleanse the body of negative energies.”

I told myself I am, then argued why I am not, conclusion- what he said. At least I am never alone.

Sorry but I don’t believe psychiatrists on nicotine. When you smoke too much you have a disease. When you are too fat you have a disease. When you are too thin you have a disease. They earn their money with prescriptions so they prescribe Zyprexa for quitting nicotine addiction. But I am curious of how they respond to nasal snuff.

Nasal snuff helps me to relax. I can snuff indoors when usually i wouldn’t be able to smoke.