Skip to main content

Currently Skimming:

12 Mental Health
Pages 289-332

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 289...
... • Heavy cannabis users are more likely to report thoughts of suicide than are nonusers. • Regular cannabis use is likely to increase the risk for develop ing social anxiety disorder.
From page 290...
... For example, for the health endpoints discussed below, literature searches were limited to articles that included the following search terms: longitudinal, prospective, and case-control.1 The committee's review of the literature focused on identifying studies relevant to answering these specific questions. In this chapter the committee will discuss the findings from 14 of the most recent, good- to fair-quality systematic reviews and from 31 primary literature articles that best address the committee's research questions of interest.
From page 291...
... SCHIZOPHRENIA AND OTHER PSYCHOSES Schizophrenia spectrum disorders and other psychotic disorders are mental health disorders characterized by three different classes of symptoms: positive symptoms (e.g., delusions, hallucinations, or disorganized or abnormal motor behavior) , negative symptoms (e.g., diminished emotional expression, lack of interest or motivation to engage in social settings, speech disturbance, or anhedonia)
From page 292...
... The authors also noted that individual studies excluded psychotic symptoms that arose solely from drug use by using scales to measure drug intoxication. In addition, this group of studies collectively adjusted for approximately 60 different potential confounders, including
From page 293...
... (2015) used the North American Prodrome Longitudinal Study2 phase 1 sample to examine the impact of the level of cannabis use on conversion to psychosis.3 From the subjects who contributed to the data, 370 were determined to be at a high risk for developing a psychotic disorder.
From page 294...
... Factors contributing to the strength of the evidence derived from the cited systematic reviews include large sample sizes, the relative homogeneity of the findings, the presence of relationships between the dose/ exposure and the risk, the studies having been controlled for confounders, and the systematic reviews having assessed for publication bias. The primary literature reviewed by the committee confirms the conclusions of the systematic reviews, including the association between cannabis use 4 T-carrying subjects have at least one allele with the polymorphism.
From page 295...
... As noted in Box 12-1, the relationship between cannabis use and cannabis use disorder, and psychoses may be multidirectional and complex. The committee found this to be consistent with their review of the summarized data demonstrating a strong and consistent association between cannabis use and the subsequent development of psychosis and psychotic disorders.
From page 296...
... Three of the most commonly explored hypotheses are: 1. Substance use may be a potential risk factor for developing mental health disorders.
From page 297...
... (2008) found mixed evidence for the effects of cannabis use on positive symptoms in patients with psychotic disorders, with studies reporting statistically significant but small associations between cannabis use and the severity of positive symptoms.
From page 298...
... It should be noted that the fourth study did not control for confounders or baseline differences in symptoms. Cognition  Three systematic reviews were identified that assessed the relationship between cannabis abuse and dependence and cognition effects (e.g., disorganized thinking)
From page 299...
... No differences were reported for assessments of attention, verbal memory, or working memory. Primary Literature Positive Symptoms In a 2004 case-control study with schizophrenic patients, Rehman and Farooq (2007)
From page 300...
... (2013) found no association between cannabis use and positive symptoms in patients with non-affective psychotic disorders, as assessed by PANSS (adjusted coefficient = 0.07; 95% CI = –0.21–0.34)
From page 301...
... (2013) , also using a cross-sectional analysis, found that previous 90-day cannabis use was not significantly associated with the severity of negative symptoms (adjusted coefficient, 0.12; 95% CI = –0.05–0.29)
From page 302...
... The primary articles reviewed indicate more mixed results than the systematic reviews. Overall, the totality of data favor the conclusion that a history of, but not recent, cannabis use is associated with statistically significant performance improvement on measures of cognitive function in patients with psychotic disorders.
From page 303...
... Systematic Reviews The committee identified one systematic review, Gibbs et al.
From page 304...
... reminded readers about the correlational nature of the study design and noted that causality could not be inferred from their conclusions. They also cautioned that the increased risk in bipolar disorders might be due to augmenting the psychotic features in frequent cannabis users (i.e., manic symptoms)
From page 305...
... Is There an Association Between Cannabis Use and the Course or Symptoms of Bipolar Disorder? Systematic Reviews The committee identified Gibbs et al.
From page 306...
... As discussed in the section above, when adjustments for alcohol and other substance use variables are included in the model as confounders, only the time to recurrence remains as significantly associated to cannabis use. There is also moderate evidence that weekly cannabis use to almost daily cannabis use can lead to the onset of mania/hypomania symptoms in adjusted models, but there is less evidence of this association for daily users of cannabis.
From page 307...
... Also, the lack of precision in measuring the frequency of cannabis use at baseline and in measuring follow-up data remains a problem. CONCLUSION 12-4  There is moderate evidence of a statistical association between regular cannabis use and increased symp toms of mania and hypomania in individuals diagnosed with bipolar disorders.
From page 308...
... . The analysis further revealed a dose–response relationship, with a slightly higher OR observed in seven studies comparing heavy cannabis use to non-cannabis users (pOR, 1.62; 95% CI = 1.21–2.16)
From page 309...
... Discussion of Findings The evidence reported suggests that cannabis use, and particularly heavy cannabis use, is associated with a small increase in the risk of developing depressive disorders. This evidence is supported by a goodquality recent systematic review that included 10 longitudinal studies with sample sizes between 700 and 45,000.
From page 310...
... . CONCLUSION 12-5  There is moderate evidence of a statistical association between cannabis use and a small increased risk for the development of depressive disorders.
From page 311...
... (2016) conducted a systematic review to address multiple questions concerning acute and chronic cannabis use, suicidal ideation, suicide attempts, and suicide.
From page 312...
... . A review of a third subset of six studies found a higher risk of suicide attempt associated with heavy cannabis use (pOR, 3.20; 95% CI = 1.72–5.94)
From page 313...
... Other limitations include the use of dichotomous response categories for suicidality when there is some evidence that additional changes to the measures are needed; the lack of adjustment for some early traumatic life events associated with suicidality; and the lack of adjustments for psychotic disorders. Discussion of Findings The evidence reported suggests that any cannabis use is related with increased suicidal ideation, augmented suicide attempts, and greater risk of death by suicide.
From page 314...
... Is There an Association Between Cannabis Use and the Development of Anxiety Disorders? Systematic Reviews One systematic review was identified that assessed the relationship between cannabis use and anxiety disorders (Kedzior and Laeber, 2014)
From page 315...
... ; and adjusted for sociodemographic characteristics, family history of substance use disorder, disturbed family environment, childhood parental loss, low self-esteem, social deviance, education, recent trauma, past and present psychiatric disorders, and respondent's history of divorce. The researchers found that cannabis use in the 12 months preceding the survey was not associated with an increased prevalence of anxiety disorders (OR, 1.0; 95% CI = 0.8–1.2)
From page 316...
... in the prospective analyses that adjusted for psychiatric comorbidity and sociodemographic factors. However, when looking at specific anxiety disorders, Cougle and colleagues (2015)
From page 317...
... However, the study had several limitations in the present study, including having a mostly white sample from upstate New York and not including environmental or social variables that could explain the relationship under study, such as family substance use or childhood psychiatric disorders. Discussion of Findings Studies examining the relationship between cannabis use and anxiety disorder show mixed results depending on whether they assessed the development of anxiety symptoms or the incidence of anxiety disorders; whether the explanatory variable was any cannabis use or cannabis use disorder; and whether there were adjustments for psychiatric comorbidity and sociodemographic factors.
From page 318...
... Is There an Association Between Cannabis Use and the Course or Symptoms of Anxiety Disorders? Systematic Reviews The committee did not identify a good- or fair-quality systematic review that reported on the association between cannabis use and the course, symptoms, and other endpoints of anxiety disorders.
From page 319...
... on cannabis use. The researchers found that harm avoidance measured at baseline was associated with more symptoms of anxiety measured 1 year later -- but only for those low in cannabis use (β = 0.15, t(329)
From page 320...
... Primary Literature The committee did not identify any good-quality primary literature that reported on the association between cannabis use and the development of PTSD and that were published subsequent to the data collection period of the most recently published good- or fair-quality systematic review addressing the research question. CONCLUSION 12-10  There is no evidence to support or refute a statistical association between cannabis use and the develop ment of posttraumatic stress disorder.
From page 321...
... participating in a methadone maintenance program, found that the severity of cannabis use was associated with the occurrence of certain PTSD symptoms, as measured by the Posttraumatic Stress Disorder Checklist–Civilian Version. Significant findings were identified for measures of reexperiencing (i.e., repeated disturbing dreams, χ2(2)
From page 322...
... as measured by the PTSD Checklist–Civilian Version and the Patient Health Questionnaire, respectively. However, cannabis users were more likely to experience suicidal ideation (p = 0.04)
From page 323...
... SUMMARY This chapter outlines the committee's efforts to review the current evidence base for the association of cannabis use with prioritized mental health conditions. The health conditions reviewed in this chapter include schizophrenia and other psychotic disorders, bipolar disorder, depression, suicide, anxiety, and PTSD.
From page 324...
... . Accordingly, the vast majority of the studies included in the systematic reviews and meta-analyses sum marized in this chapter were observational studies.
From page 325...
... Given the use of some primary studies in more than one systematic review, the number of systematic reviews or meta-analyses may not, by themselves, indicate a stronger body of evidence. While it is easy to understand how multiple reviews might identify similar stud ies, it is also of concern when reviews identify different studies.
From page 326...
... There is moderate evidence of a statistical association between cannabis use and: • Better cognitive performance among individuals with psychotic disorders and a history of cannabis use (12-2a) • Increased symptoms of mania and hypomania in individuals diagnosed with bipolar disorders (regular cannabis use)
From page 327...
... 2012. Methodol ogy and reporting of systematic reviews and meta-analyses of observational studies in psychiatric epidemiology: Systematic review.
From page 328...
... 2006. Lifetime positive symptoms in patients with schizophrenia and cannabis abuse are partially explained by co-morbid addiction.
From page 329...
... 2006. Quality assessment of observational studies is not commonplace in systematic reviews.
From page 330...
... 2011. The relation ship between substance use and posttraumatic stress disorder in a methadone mainte nance treatment program.
From page 331...
... 2008. Effects of cannabis use on outcomes of psychotic disorders: Systematic review.


This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More information on Chapter Skim is available.