Course of substance misuse and daily tobacco use in first-episode psychosis

Background: Study of the course of substance misuse and daily tobacco use in first-episode psychosis may enhance detection and treatment of these substance-related problems. Methods: This 15-month follow-up study examined the course of substance misuse and daily tobacco use in 103 individuals treated for first-episode psychosis. Results: Three-quarters (72.6%) of patients with lifetime substance misuse, or half (51.5%) of all patients, continued substance misuse (primarily cannabis) during the 15-month follow-up period. There was a significant reduction in the rate of any substance misuse (70.9% versus 53.4%) but not daily tobacco use (76.7% versus 75.7%) between baseline and 15-month follow-up. Patients who continued substance misuse showed a significant reduction in the severity and frequency of substance use between baseline and follow-up. Patients who continued substance misuse were more likely to be younger, male and single, less likely to have completed secondary school, and more likely to have had more severe cannabis use prior to entry to treatment compared to patients who ceased substance misuse. Discussion: A significant proportion of young patients treated for first-episode psychosis are at risk of mental and physical health problems associated with substance misuse and/or regular tobacco use. (c) 2005 Elsevier B.V. All rights reserved.

The role of alcohol expectancy and drinking refusal self-efficacy beliefs in university student drinking

Aims: University student alcohol misuse is a considerable problem. Alcohol expectancy research has contributed significantly to our understanding of problem drinking in young adults. Most of this research has investigated positive expectancy alone. The current study utilized two measures of alcohol expectancy, the alcohol expectancy questionnaire (AEQ) and the drinking expectancy profile [consisting of the drinking expectancy questionnaire (DEQ) and the drinking refusal self-efficacy questionnaire] to predict severity of alcohol dependence, frequency of drinking, and the quantity of alcohol consumed per occasion. Methods: Measures of drinking behaviour and alcohol expectancy were completed by 174 undergraduate university students. Results: Positive alcohol expectancy factors accounted for significant variance in all three drinking indices, with the DEQ adding additional variance to AEQ scores on frequency and severity of alcohol dependence indices. Negative expectancy did not add incremental variance to the prediction of drinking behaviour in this sample. Drinking refusal self-efficacy and dependence beliefs added additional variance over positive and negative expectancies in the prediction of all three drinking parameters. Conclusions: Positive expectancy and drinking refusal self-efficacy were strongly related to university student drinking. The incorporation of expectancy as a means of informing prevention approaches in tertiary education shows promise.

Substance misuse in first-episode psychosis: 15-month prospective follow-up study

Background Well-designed prospective studies of substance misuse in first-episode psychosis can improve our understanding of the risks associated with comorbid substance misuse and psychosis. Aims To examine the potential effects of substance misuse on in-patient admission and remission and relapse of positive symptoms in first-episode psychosis. Method The study was a prospective 15-month follow-up investigation of 103 patients with first-episode psychosis recruited from three mental health services. Results Substance misuse was independently associated with increased risk of in-patient admission, relapse of positive symptoms and shorter time to relapse of positive symptoms after controlling for potential confounding factors, Substance misuse was not associated with remission or time to remission of positive symptoms. Heavy substance misuse was associated with increased risk of in-patient admission, relapse and shorter time to relapse. Conclusions Substance misuse is an independent risk factor for a problematic recovery from first-episode psychosis.

Substance P preferentially inhibits large conductance nicotinic ACh receptor channels in rat intracardiac ganglion neurons

The effects of substance P (SP) on nicotinic acetylcholine (ACh)-evoked currents were investigated in parasympathetic neurons dissociated from neonatal rat intracardiac ganglia using standard whole cell, perforated patch, and outside-out recording configurations of the patch-clamp technique. Focal application of SP onto the soma reversibly decreased the peak amplitude of the ACh-evoked current with half-maximal inhibition occurring at 45 mu M and complete block at 300 mu M SP. Whole cell current-voltage (I-V) relationships obtained in the absence and presence of SP indicate that the block of ACh-evoked currents by SP is voltage independent. The rate of decay of ACh-evoked currents was increased sixfold in the presence of SP (100 mu M), suggesting that SP may increase the rate of receptor desensitization. SP-induced inhibition of ACh-evoked currents was observed following cell dialysis and in the presence of either 1 mM 8-Br-cAMP, a membrane-permeant cAMP analogue, 5 mu M H-7, a protein kinase C inhibitor, or 2 mM intracellular AMP-PNP, a nonhydrolyzable ATP analogue. These data suggest that a diffusible cytosolic second messenger is unlikely to mediate SP inhibition of neuronal nicotinic ACh receptor (nAChR) channels. Activation of nAChR channels in outside-out membrane patches by either ACh (3 mu M) or cytisine (3 mu M) indicates the presence of at least three distinct conductances (20, 35, and 47 pS) in rat intracardiac neurons. In the presence of 3 mu M SP, the large conductance nAChR channels are preferentially inhibited. The open probabilities of the large conductance classes activated by either ACh or cytisine were reversibly decreased by 10- to 30-fold in the presence of SP. The single-channel conductances were unchanged, and mean apparent channel open times for the large conductance nAChR channels only were slightly decreased by SP. Given that individual parasympathetic neurons of rat intracardiac ganglia express a heterogeneous population of nAChR subunits represented by the different conductance levels, SP appears to preferentially inhibit those combinations of nAChR subunits that form the large conductance nAChR channels. Since ACh is the principal neurotransmitter of extrinsic (vagal) innervation of the mammalian heart, SP may play an important role in modulating autonomic control of the heart.