The associations of cannabis and methamphetamine use with cognitive performance over the first 2 years of treatment in schizophrenia spectrum disorders.

AIM: Cognitive deficits are a core feature of schizophrenia, and comorbid substance use may be a contributory factor. Methamphetamine use has been associated with cognitive impairment in schizophrenia, while associations with cannabis use are less clear-cut. This study aimed to investigate the associations of cannabis and methamphetamine use with cognitive performance in first-episode schizophrenia spectrum disorders over the first 2 years of treatment. METHODS: This was a longitudinal cohort study in 81 patients treated with flupenthixol decanoate according to a standardized protocol over 24 months. Cognitive performance was assessed with the Measurement and Treatment Research to Improve Cognition in Schizophrenia Cognitive Consensus Battery at four time points, and urine testing for cannabis and methamphetamine was conducted at six time points. We used linear mixed-effect models for repeated measures to assess visit-wise changes in composite cognitive scores in patients (n = 91) compared to matched controls without psychiatric or medical disorders (n = 100). Linear regression models were constructed to examine pre-treatment and end-point effects in patients. RESULTS: Compared to controls, patients exhibited greater cognitive impairments at baseline, which improved with treatment, but remained significantly lower throughout. The number of positive methamphetamine, but not cannabis, tests predicted less cognitive improvement in patients. CONCLUSIONS: Our findings suggest a negative association between methamphetamine and cognition, but not cannabis.

Hair cortisol levels in schizophrenia and metabolic syndrome.

AIM: Individuals with schizophrenia demonstrate higher rates of metabolic syndrome (MetS) than the general population. Hair cortisol concentrations (HCC) reflect longer-term cortisol secretion and can provide additional insights into the role of the hypothalamic pituitary adrenal (HPA) axis in schizophrenia and co-occurring MetS. METHODS: In a case-control study of 16 patients with schizophrenia (11 first episode psychosis [FEP] and 5 chronic) and 21 controls hair samples, representing a 3-month retrospective window of cortisol, were collected and analysed utilizing liquid chromatography tandem mass spectrometry. We investigated whether schizophrenia and MetS co-occurrence were associated with HCC utilizing multivariate regression models. We also explored the longitudinal trajectory of HCC in FEP patients by conducting a mixed models analysis. RESULTS: At baseline HCC were significantly lower (Cohen's d = 0.88) in patients with schizophrenia than in controls (p = .014). HCC increased from baseline to month-12 in FEP patients compared to controls, demonstrating a trend towards significance (p = .097). MetS was not associated with HCC at baseline, but HCC increased significantly from baseline to month-12 in relation to MetS (p = .037). CONCLUSIONS: In a subgroup of schizophrenia patients, psychosis may be associated with a blunted HPA axis with lower long-term cortisol output. MetS was associated with an increase in HCC and elevated cortisol levels observed in schizophrenia may be related to increased rates of MetS in schizophrenia patients.