Cannabis Use and Cognition in Schizophrenia

People with schizophrenia frequently report cannabis use, and cannabis may be a risk factor for schizophrenia, mediated through effects on brain function and biochemistry. Thus, it is conceivable that cannabis may also influence cognitive functioning in this patient group. We report data from our own laboratory on the use of cannabis by schizophrenia patients, and review the existing literature on the effects of cannabis on cognition in schizophrenia and related psychosis. Of the 23 studies that were found, 14 reported that the cannabis users had better cognitive performance than the schizophrenia non-users. Eight studies reported no or minimal differences in cognitive performance in the two groups, but only one study reported better cognitive performance in the schizophrenia non-user group. Our own results confirm the overall impression from the literature review of better cognitive performance in the cannabis user group. These paradoxical findings may have several explanations, which are discussed. We suggest that cannabis causes a transient cognitive breakdown enabling the development of psychosis, imitating the typical cognitive vulnerability seen in schizophrenia. This is further supported by an earlier age of onset and fewer neurological soft signs in the cannabis-related schizophrenia group, suggesting an alternative pathway to psychosis

Left Temporal Lobe Structural and Functional Abnormality Underlying Auditory Hallucinations in Schizophrenia

In this article, we have reviewed recent findings from our laboratory, originally presented in Hugdahl et al. (2008). These findings reveal that auditory hallucinations in schizophrenia should best be conceptualized as internally generated speech mis-representations lateralized to the left superior temporal gyrus and sulcus, not cognitively suppressed due to enhanced attention to the ‘voices’ and failure of fronto-parietal executive control functions. An overview of diagnostic questionnaires for scoring of symptoms is presented together with a review of behavioral, structural, and functional MRI data. Functional imaging data have either shown increased or decreased activation depending on whether patients have been presented an external stimulus during scanning. Structural imaging data have shown reduction of grey matter density and volume in the same areas in the temporal lobe. We have proposed a model for the understanding of auditory hallucinations that trace the origin of auditory hallucinations to neuronal abnormality in the speech areas in the left temporal lobe, which is not suppressed by volitional cognitive control processes, due to dysfunctional fronto-parietal executive cortical networks

Sexual Dysfunction and Hyperprolactinemia in Male Psychotic Inpatients: A Cross-Sectional Study

Introduction. Sexual dysfunction (SD) and hyperprolactinemia are frequently reported in patients with psychotic disorders and have the potential for severe complications but investigations in males are particularly scarce. The primary aims were to determine the prevalence of SD and hyperprolactinemia in male patients and to investigate whether associations exist between SD and prolactin levels. Methods. Cross-sectional data were obtained at discharge from the hospital or 6 weeks after admittance for patients acutely admitted for psychosis and treated with a second-generation antipsychotic drug. Results. Half the patients reported diminished sexual desire and more than a third reported erectile and ejaculatory dysfunctions with no differences among the drugs. More than half the sample was hyperprolactinemic. No association was found between prolactin levels and SD. Conclusion. High rates of SD and hyperprolactinemia were found in male patients and should be a treatment target. SD and hyperprolactinemia were not correlated

Cognitive profile in ultra high risk for psychosis and schizophrenia: A comparison using coordinated norms

Background: Cognitive impairment is not only a core aspect of schizophrenia but also commonly observed in help-seeking youth at ultra high risk for psychosis (UHR), with potential implications for prognosis and individualized treatment. However, there is no consensus on the cognitive profile in the UHR state, partly due to lack of valid comparisons of performance in established schizophrenia and UHR. Objectives: To compare the cognitive functioning and profile of UHR subjects to a sample with schizophrenia, they were split into two groups based on duration of illness. Comparisons were made using coordinated norms based on healthy controls reflecting the younger UHR age spectrum. Methods: Participants for UHR (n = 51) and schizophrenia groups (n = 19 and n = 22) were included from the Prevention of Psychosis and Bergen Psychosis 2 projects. All subjects completed a comprehensive neurocognitive test battery aiming to measure speed of processing, working memory, verbal learning, reasoning, and problem solving, as well as visual problem solving. Cognitive functioning was compared between groups based on coordinated norms using z-scores derived by regression modeling from an age-matched healthy control group (n = 61). Results: UHR subjects showed significantly impaired speed of processing (p 3 years for speed of processing and working memory (both p < 0.001). There were no significant differences in performance between the UHR group and the group with duration of schizophrenia <3 years. Conclusion: Cognitive performance is impaired in UHR subjects as compared to healthy controls and should thus be monitored when a person is deemed at high risk of psychotic illness. Spatial skills, as measured by tests using physical objects, appear less affected than other domains. The pattern of impairment is similar to that of a group with recent onset schizophrenia but is less severe than in a group with duration of illness <3 years.publishedVersio

The positive link between executive function and lifetime cannabis use in schizophrenia is not explained by current levels of superior social cognition

There has been a growing link between a history of cannabis use and neurocognitive performance in patients with schizophrenia. Fewer neurocognitive deficits may be a marker of the superior social cognition needed to obtain illicit substances, or cannabis use may indicate a distinct path to schizophrenia with less neurocognitive vulnerability. This study sought to determine whether the relationship of cannabis use and executive function exists independently of social cognition. Eighty-seven patients with schizophrenia were administered measures of social cognition and executive function. Social cognition was assessed using the Bell-Lysaker Emotion Recognition Test to measure affect recognition, and the Eyes and Hinting Tests to measure theory of mind. Executive function was assessed by the Mental Flexibility component of the Delis-Kaplan Executive Functioning Scale. The relations between the variables were examined with structural equation modeling. Cannabis use positively related to executive function, negatively related to affect recognition, and had no relationship with theory of mind. There were no indirect effects of other illicit substances on amount of regular cannabis use. Alcohol use was related to worse affect recognition. The relationship between cannabis use and better executive function was supported and was not explained by superior social cognitio

Cognitive change and antipsychotic medications: Results from a pragmatic rater-blind RCT

Cognitive impairment is a core aspect of psychotic disorders and difficult to treat. Atypical antipsychotics (AAs) might have differential effects on cognitive impairment, but rigid study designs and selective sampling limit the generalizability of existing findings. This pragmatic, semi-randomized, industry-independent study aimed to investigate and compare the effect of amisulpride, aripiprazole and olanzapine on cognitive performance in psychosis over a 12-month period controlling for diagnostic group. This sub study of the BeSt InTro study recruited adults with ongoing psychosis in the schizophrenia spectrum of disorders (ICD-10 diagnoses F20-F23, F25, F28 or F29; n = 104) from Bergen and Stavanger, Norway; and Innsbruck, Austria. Participants were randomized to amisulpride, aripiprazole, or olanzapine and they completed neuropsychological assessments at baseline, 6 weeks, 6 and 12 months. The test battery targeted working memory, verbal ability, and processing speed. We used Longitudinal mixed effect (LME) models to assess cognitive change for intention to treat (ITT) and per protocol (PP) medication groups, as well as comparing cognitive performance between F20 and non-F20 participants. The sample baseline global cognitive performance t-score was 42.20. Global performance improved significantly to every follow-up, including for the F20 group. There were however no significant differences in cognitive change over time between neither ITT nor PP medication groups.publishedVersio

Changes in substance use during outpatient treatment for substance use disorders: a prospective Norwegian cohort study from 2016 to 2020

Background Continuous use of amphetamines, alcohol, benzodiazepines, cannabis, cocaine, or opioids contributes to health impairments, increased morbidity, and overdose deaths among patients with substance use disorders (SUDs). This study evaluates the impact of inpatient detoxification, injecting substance use, age, and gender on substance use over time among patients undergoing outpatient SUD treatment. Methods We used data from a cohort of SUD patients in Norway obtained from health assessments of self-reported substance use and sociodemographic and clinical factors. A total of 881 substance use measurements, including substances and frequency of use, were assessed for 708 SUD patients in 2016–2020. Of those, 171 patients provided two or more substance use measurements. The total substance use was calculated, creating a substance use severity index (SUSI), ranging from zero (no use) to one (daily use of all substances). We defined baseline as the first substance use measurement when the measurements were listed chronologically. Time was defined as years from baseline. We used a linear mixed model to analyze the SUSI at baseline and over time, and its associations with inpatient detoxification, injecting substance use, gender, and age, presented with coefficients and 95% confidence intervals (CI). Results No longitudinal changes in the SUSI were found compared with baseline (change in SUSI (cSUSI): 0.04, 95% CI: − 0.05;0.13, p = 0.397). Likewise, “inpatient detoxification” was not associated with changes in the SUSI compared with “no inpatient detoxification” (cSUSI: 0.00, 95% CI: − 0.04;0.04, p = 0.952). However, injecting substances were associated with a higher SUSI than not injecting substances at baseline (difference in SUSI: 0.19, 95% CI: 0.16;0.21, p = < 0.001), and starting to inject substances was associated with increasing SUSI over time compared with not starting to inject substances (cSUSI: 0.11, 95% CI: 0.07;0.15, p = < 0.001). Gender was not significantly associated with changes in the SUSI (cSUSI: − 0.04, 95% CI: − 0.07;0.00, p = 0.052), while patients over 60 years of age had a lower SUSI than those under the age of 30 at baseline (difference in SUSI: − 0.08, 95% CI: − 0.14;− 0.01, p = 0.018), with no change over time (cSUSI: − 0.05, 95% CI: − 0.16;0.05, p = 0.297). Conclusion The present study demonstrates that inpatient detoxification was not associated with substance use changes over time for patients undergoing outpatient SUD treatment. Otherwise, injecting substance use was a particular risk factor for a high level of substance use. Future research needs to evaluate the impact of other treatment approaches on substance use, ideally in randomized controlled trials.publishedVersio

Akathisia and atypical antipsychotics. Relation to suicidality, agitation and depression in a clinical trial

Objective: Akathisia is among the most unpleasant side effects related to antipsychotic drug (AP) use, and possible associations between akathisia and agitation, depression and suicidal behaviour, respectively, have been described in previous literature. New generation antipsychotics are however regarded less prone to induce this particular adverse effect compared to older drugs, but evidence is incomplete and in need of confirmation from clinically relevant samples and settings. We, therefore, aim to investigate akathisia at hospital discharge for patients consecutively admitted with acute-phase psychosis and treated with atypical antipsychotics according to guideline-concordant clinical practice. Methods: This exploratory study is part of a naturalistic randomised controlled study in patients admitted with acute phase psychosis (N = 109). We report cross-sectional data at discharge/first follow-up after acute psychiatric hospital admission for patients with schizophrenia and related psychotic disorders. Results: There were statistically significant positive associations between akathisia and the following; suicidality in men (Beta 0.306, p = 0.048), but not in women; agitation in those previously unexposed to antipsychotics (Beta 0.288, p = 0.047) and depression in those exposed to antipsychotics before hospital admittance (Beta 0.375, p = 0.031). Conclusion: Main findings were that akathisia is still a prevalent side effect in a clinically relevant sample of patients treated with atypical antipsychotics. Our results suggest that akathisia is significantly associated with depression, suicidality and agitation in different subgroups of patients receiving APs. Akathisia can be detrimental and the relations between akathisia and depression, suicidality and agitation should be investigated further in prospective, hypothesis-testing studies with larger samples.publishedVersio

Dynamic Functional Connectivity Patterns in Schizophrenia and the Relationship With Hallucinations

There is a wealth of evidence showing aberrant functional connectivity (FC) in schizophrenia but with considerable variability in findings across studies. Dynamic FC is an extension of traditional static FC, in that such analyses allow for explorations of temporal changes in connectivity. Thereby they also provide more detailed information on connectivity abnormalities in psychiatric disorders such as schizophrenia. The current study investigated dynamic FC in a sample of 80 schizophrenia patients and 80 matched healthy control subjects, replicating previous findings of aberrant dwell times in specific FC states, and further supporting a role for default mode network (DMN) dysfunction. Furthermore, relationships with hallucinations, a core symptom of schizophrenia, were explored. Two measures of hallucinations were used, one measure of current hallucination severity assessed on the day of scanning, and one trait-measure where hallucinations were assessed repeatedly over the course of 1 year. Current hallucination severity did not show a significant relationship with dynamic FC. However, the trait-measure of hallucination proneness over 1 year showed a significant relationship with dynamic FC. Patients with high hallucination proneness spent less time in connectivity states characterized by strong anti-correlation between the DMN and task-positive networks. The findings support theoretical models of hallucinations which have proposed an instability of the DMN and impaired cognitive control in patients with hallucinations. Furthermore, the results point to hallucination proneness as a potential marker for identifying distinct subgroups of schizophrenia patients.publishedVersio

Illicit substances detected through high-resolution MS analysis in urine samples are associated with greater symptom burden in patients with psychosis

Background The prevalence of new psychoactive substances (NPS) in acute psychotic patients has not been investigated systematically. We applied a highly sensitive and specific mass spectrometry method for detection of NPS as well as traditional drugs of abuse (including illicit or prescription substances) in order to assess their prevalence and associations with symptom severity. Identification of these substances is useful in both the diagnostic process and evaluation of treatment effects. Methods Demographic data, results from the Positive and Negative Syndrome Score (PANSS) and Calgary Depression Scale for Schizophrenia (CDSS) and urine samples from admission were collected from 53 patients recruited into a clinical study of psychosis during 2014-2017. Urine samples were analysed with liquid chromatography high resolution mass spectrometry (LC-QTOF-MS), through both highly specific detection of 191 substances using internal standards and untargeted screening by means of pre-defined libraries. PANSS and CDSS scores in patients with or without drugs of abuse were compared. Results Potential drugs of abuse, i.e. drugs that could be used in a controlled therapeutic or a non-prescribed manner, were detected in samples from 20 of the 53 patients. Seven samples contained illicit drugs, but no NPS were detected. In this small patient subgroup, PANSS total score and CDSS score were significantly higher than in patients with negative urine sample results. Conclusion Drug screening could play an important role in the differential diagnostic evaluation of patients admitted with psychotic symptoms. Although no NPS were detected in the study population, we found other substances that were associated with psychotic and depressive symptoms.publishedVersio