Cognitive changes in patients with acute phase psychosis--effects of illicit drug use

Thought Suppression in Primary Psychotic Disorders and Substance/Medication Induced Psychotic Disorder

Introduction: First episode-psychosis (FEP) represents a stressful/traumatic event for patients. To our knowledge, no study to date has investigated thought suppression involved in FEP in a Romanian population. Our objective was to investigate thought suppression occurring during FEP within primary psychotic disorders (PPD) and substance/medication induced psychotic disorders (SMIPD). Further, we examined the relationship between thought suppression and negative automatic thoughts within PPD and SMIPD. Methods: The study included 30 participants (17 females) with PPD and 25 participants (10 females) with SMIPD. Psychological scales were administered to assess psychotic symptoms and negative automatic thoughts, along a psychiatric clinical interview and a biochemical drug test. Results: Participants in the PPD group reported higher thought suppression compared to SMIPD group. For the PPD group, results showed a positive correlation between thought suppression and automatic thoughts. For the SMIPD group, results also showed a positive correlation between thought suppression and automatic thoughts. Conclusions: Patients with PPD rely more on thought suppression, as opposed to SMIPD patients. Thought suppression may be viewed as an unhealthy reaction to FEP, which is associated with the experience of negative automatic thoughts and might be especially problematic in patients with PPD. Cognitive behavioral therapy is recommended to decrease thought suppression and improve patients’ functioning.

The importance of clinical normative data for conceptualizing neuropsychological deficits in people with schizophrenia spectrum disorders

OBJECTIVE

To create clinical normative data tables for Norwegian patients with schizophrenia spectrum disorders, to examine whether clinical normative data from Norway differs from similar normative data from Canada and the U.S., and to illustrate the usefulness of such data.

METHOD

A nationally representative sample of 335 patients from psychiatric hospitals in Bergen, Norway was included. Inclusion criteria were 18-39 years of age, Norwegian as first language, and symptoms of schizophrenia, psychosis, or hallucinations. Comorbid substance abuse was recorded in 134 (40.0%). All completed the Norwegian version of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS).

RESULTS

The average scores of patients with schizophrenia spectrum disorders were approximately one to two standard deviations below the mean for healthy adults. There were no significant differences in scores between patients with or without comorbid substance abuse. Men had higher scores than women. Clinical normative reference value look-up tables were created.

CONCLUSIONS

Clinical normative values were very similar to values from Canada and the U.S. Clinical normative data, as a supplement to standard healthy normative data, can be used to describe patients' cognitive performance in terms of expectation for their peer group which can be useful for multidisciplinary treatment planning.

Meta-analysis of neurocognition in young psychosis patients with current cannabis use

OBJECTIVE

Adult psychosis patients (i.e. over the age of 25 years) who are also lifetime cannabis users (CANN±) appear to exhibit superior cognition compared to never-using patients (CANN-). The objective of this meta-analysis was to evaluate the cognitive differences between CANN- and patients who currently use cannabis (CANN+) (i.e. during the CANN± patients' cannabis-using stage). Specifically, focusing on young patients under the age of 25 years, the typical stage of both psychosis- and cannabis-onset.

METHOD

Of the 308 studies identified through database searches and secondary referencing, 14 compared neurocognition of CANN+ and CANN- in young people with psychotic disorders (mean age between 15 and 45 years). Effect sizes were extracted using neurocognitive test performance between CANN+ and CANN- and random effects modelling was conducted on pooled ES and moderator analyses.

RESULTS

CANN+ performed worse on several cognitive domains (i.e. premorbid IQ, current IQ, verbal learning, verbal working memory, motor inhibition) compared to CANN-. The association between age and performance in CANN+ cognition was varied, with older age predictive of worse performance in processing speed, sustained attention, verbal memory, and better performance in verbal learning and very fluency. Of note, CANN+ outperformed CANN- in tests of conceptual set-shifting.

CONCLUSION

These results are consistent with previous findings indicating that CANN+ demonstrate poorer neurocognition than CANN-; and that this is exacerbated with increasing age. Our findings demonstrate significant cognitive differences between patients with CANN+ versus CANN- even at early-onset psychosis, which could suggest a different underlying mechanism towards psychosis for cannabis users.

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 cognition.

The Cannabis Pathway to Non-Affective Psychosis may Reflect Less Neurobiological Vulnerability

There is a high prevalence of cannabis use reported in non-affective psychosis. Early prospective longitudinal studies conclude that cannabis use is a risk factor for psychosis, and neurochemical studies on cannabis have suggested potential mechanisms for this effect. Recent advances in the field of neuroscience and genetics may have important implications for our understanding of this relationship. Importantly, we need to better understand the vulnerability × cannabis interaction to shed light on the mediators of cannabis as a risk factor for psychosis. Thus, the present study reviews recent literature on several variables relevant for understanding the relationship between cannabis and psychosis, including age of onset, cognition, brain functioning, family history, genetics, and neurological soft signs (NSS) in non-affective psychosis. Compared with non-using non-affective psychosis, the present review shows that there seem to be fewer stable cognitive deficits in patients with cannabis use and psychosis, in addition to fewer NSS and possibly more normalized brain functioning, indicating less neurobiological vulnerability for psychosis. There are, however, some familiar and genetic vulnerabilities present in the cannabis psychosis group, which may influence the cannabis pathway to psychosis by increasing sensitivity to cannabis. Furthermore, an earlier age of onset suggests a different pathway to psychosis in the cannabis-using patients. Two alternative vulnerability models are presented to integrate these seemingly paradoxical findings.