The Relationship Between Cannabis, Cognition, and Schizophrenia: It's Complicated.

The consequences of cannabis use, especially in the context of schizophrenia, have gained increased importance with the legalization of cannabis in North America and across the globe. Cannabis use has multifaceted impacts on cognition in schizophrenia patients and healthy subjects. Healthy subjects, particularly those who initiated cannabis use at earlier ages and used high-potency cannabis for longer durations, exhibited poorer cognition mainly in working memory and attention. Cannabis use in schizophrenia has been associated with symptom exacerbation, longer and more frequent psychotic episodes, and poorer treatment outcomes. However, cannabis-using patients have better overall cognitive performance compared to patients who were not cannabis users. Interestingly, these effects were only apparent in lifetime cannabis users, but not in current (or within last 6 months) users. Moreover, higher frequency and earlier age of cannabis use initiation (i.e., before 17 years of age) were associated with better cognitive performance, although they had an earlier illness onset. Three possible hypotheses seem to come forward to explain this paradox. First, some components of cannabis may have antipsychotic or cognitive-enhancing properties. Secondly, chronic cannabis use may alter endocannabinoid signaling in the brain which could be a protective factor for developing psychosis or cognitive impairments. A third explanation could be their representation of a phenotypically distinct patient group with more intact cognitive functioning and less neurodevelopmental pathology. Multiple factors need to be considered to understand the complex relationship between cannabis, cognitive function, and schizophrenia. In short, age at initiation, duration and rate of cannabis use, abstinence duration, co-use of substances and alcohol, prescribed medications, relative cannabinoid composition and potency of cannabis, presence of genetic and environmental vulnerability factors are prominent contributors to the variability in outcomes. Animal studies support the disruptive effects of Δ9-tetrahydrocannabinol (THC) administration during adolescence on attention and memory performance. They provide insights about interaction of cannabinoid receptors with other neurotransmitter systems, such as GABA and glutamate, and other regulatory molecules, such as PSD95 and synaptophysin. Cannabidiol (CBD), on the other hand, can improve cognitive deficits seen in neurodevelopmental and chemically-induced animal models of schizophrenia. Future studies focusing on bridging the translational gaps between human and animal studies, through the use of translationally relevant methods of exposure (e.g., vaping), consistent behavioral assessments, and congruent circuit interrogations (e.g., imaging) will help to further clarify this complex picture.

Alcohol and Vaporized Nicotine Co-exposure During Adolescence Contribute Differentially to Sex-Specific Behavioral Effects in Adulthood.

INTRODUCTION: Co-occurrence of e-cigarette use and alcohol consumption during adolescence is frequent. Here, we examined whether adolescent co-exposure to alcohol drinking and vaporized nicotine would impact reward- and cognition-related behaviors in adult male and female rats during adulthood. AIMS AND METHODS: Four groups of male and female Sprague Dawley rats (n = 8-11/group/sex) received either nicotine (JUUL 5% nicotine pods) or vehicle vapor for 10 minutes daily between postnatal days 30-46, while having continuous voluntary access to ethanol and water during this time in a two-bottle preference design. Upon reaching adulthood, all rats underwent behavioral testing (ie, Pavlovian conditioned approach testing, fear conditioning and a two-bottle alcohol preference). RESULTS: A sex-dependent effect, not related to adolescent nicotine or alcohol exposure, on alcohol drinking in adulthood was found, such that females had a higher intake and preference for alcohol compared to males; both male and female adult rats also had greater alcohol preference compared to their alcohol preference as adolescents. Male rats exposed to vaporized nicotine with or without alcohol drinking during adolescence exhibited altered reward-related learning in adulthood, evidenced by enhanced levels of sign-tracking behavior. Male rats that drank alcohol with or without nicotine vapor in adolescence showed deficits in associative fear learning and memory as adults. In contrast, these effects were not seen in female rats exposed to alcohol and nicotine vapor during adolescence. CONCLUSIONS: The present study provides evidence that co-exposure to alcohol and vaporized nicotine during adolescence in male, but not female, rats produces long-term changes in reward- and cognition-related behaviors. IMPLICATIONS: These findings enhance our understanding of the effects of alcohol drinking and nicotine vapor exposure in adolescence. Moreover, they highlight potential sex differences that exist in the response to alcohol and nicotine vapor, underscoring the need for follow-up studies elucidating the neurobiological mechanisms that drive these sex differences, as well as the long-term effects of alcohol and nicotine vapor use.

Comorbidity of body dysmorphic disorder and eating disorders: severity of psychopathology and body image disturbance.

OBJECTIVE: The current study examined comorbidity and clinical correlates of eating disorders in a large sample of individuals with body dysmorphic disorder (BDD). METHOD: Two hundred individuals with DSM-IV (4th ed. of the Diagnostic and Statistical Manual of Mental Disorders. Washington, DC: American Psychiatric Association; 1994) BDD completed reliable interviewer-administered and self-report measures, including diagnostic assessments and measures of body image, symptom severity, delusionality, psychosocial functioning, quality of life (QOL), and history of psychiatric treatment. RESULTS: A total of 32.5% of BDD subjects had a comorbid lifetime eating disorder: 9.0% had anorexia nervosa, 6.5% had bulimia nervosa, and 17.5% had an eating disorder not otherwise specified. Comparisons of subjects with a comorbid lifetime eating disorder (n = 65) and subjects without an eating disorder (n = 135) indicated that the comorbid group was more likely to be female, less likely to be African American, had more comorbidity, and had significantly greater body image disturbance and dissatisfaction. There were no significant group differences in BDD symptom severity, degree of delusionality, or suicidal ideation or attempts. Functioning and QOL were notably poor in both groups, with no significant between-group differences. However, a higher proportion of the comorbid eating disorder group had been hospitalized for psychiatric problems. This group had also received a greater number of psychotherapy sessions and psychotropic medications. CONCLUSION: Eating disorders appear relatively common in individuals with BDD. BDD subjects with a comorbid eating disorder differed on several demographic variables, had greater comorbidity and body image disturbance, and had received more mental health treatment than subjects without a comorbid eating disorder. These findings have important implications for the assessment and treatment of these comorbid body image disorders.

Assessing olfaction in the neuropsychological exam: the relationship between odor identification and cognition in older adults.

The relationship between odor identification and cognition has not been previously well characterized. The neuroanatomy of the olfactory system and the frequent finding of olfactory dysfunction in neurodegenerative diseases suggest a likely relationship between odor identification and memory, language, and executive functioning, though previous studies have often failed to demonstrate the expected relationship. The current study examined this relationship in across a continuum of ability levels (N=100). Strongest correlations were found between odor identification and language, most aspects of memory, and a measure of general cognitive functioning. Significant but more modest correlations were seen between odor identification and attention, motor, visuospatial, and executive functions. A regression analysis revealed language as the only significant predictor of olfactory performance. These findings suggest that odor identification is most closely associated with other measures of temporo-limbic functioning. The implications of these findings, particularly in consideration of the assessment of older adults, are discussed.

Assessment of mood state in dementia by use of the visual analog mood scales (VAMS).

OBJECTIVE: The assessment of mood states in individuals with dementia is a challenging yet clinically useful task. The purpose of the present study was to examine the validity of the Visual Analog Mood Scales (VAMS) in individuals with dementia. METHODS: Thirty-one patients who met diagnostic criteria for dementia completed the VAMS and a modified Profile of Mood States. RESULTS: Authors found good convergent validity between all monotrait-heteromethod mood states. Excellent discriminant validity was found for VAMS Happy, Confused, Angry, and Energetic scales. CONCLUSION: These results provide evidence for the validity of the VAMS in patients with dementia.