Does a history of cannabis use influence onset and course of schizophrenia?

INTRODUCTION: While evidence strongly supports a causal effect of cannabis on psychosis, it is less clear whether the symptom pattern, clinical course, and outcomes differ in cases of schizophrenia with and without a background of cannabis use. METHODS: Analysis of medical records from a longitudinal follow-up of Swedish conscripts with data on cannabis use in adolescence and subsequent incidence of schizophrenia. One hundred sixty patients with schizophrenia were assessed using the OPCRIT protocol. Cases were validated for diagnosis schizophrenia according to OPCRIT. RESULTS: Patients with a cannabis history (n = 32), compared to those without (n = 128), had an earlier age at onset, a higher number of hospital admissions and a higher total number of hospital days. There was no significant difference in type of onset and clinical symptom profiles between the groups. CONCLUSION: Our findings indicate that the disease burden of schizophrenia is greater in individuals who use cannabis during adolescence. Strengthening evidence on causality and teasing out long-term effects of pre-illness cannabis use from continued post-illness has clinical implications for improving schizophrenia outcomes.

ACT-enhanced group behavior therapy for trichotillomania and skin-picking disorder: A feasibility study.

OBJECTIVE: To evaluate the feasibility and efficacy of ACT-enhanced Group Behavior Therapy (AEGBT) for mixed diagnosis groups including patients with trichotillomania (TTM) and skin-picking disorder (SPD) in routine psychiatric care. METHOD: Adult patients (N = 40) with TTM and/or SPD received 10 weeks of AEGBT followed by five booster sessions. The primary outcome measure for TTM was the Massachusetts General Hospital Hairpulling Scale (MGH-HPS) and for SPD the Skin Picking Scale-Revised (SPS-R), assessed at posttreatment and at booster sessions. RESULTS: Results showed significant reductions in hair pulling and skin-picking severity from baseline to posttreatment and large effect sizes at posttreatment. Improvements remained significant at the 12-month follow-up for patients with SPD, but not for patients with TTM. Group attendance was high and few patients dropped out from treatment. The group format enabled therapists to see 25% more patients compared with an individual format. CONCLUSION: The results provide initial support for the feasibility and efficacy of an adapted treatment approach for TTM and SPD.

Emotional perception modulated by an opioid and a cholecystokinin agonist.

RATIONALE: The cholecystokinin (CCK) and opioid neuromodulatory systems work in an antagonistic fashion and can modulate emotional states and noxious input in opposite directions. In this behavioral study, we generalize this idea and suggest that CCK and opioids can modulate the processing of other external signals, e.g., visual stimuli rather than only noxious input. OBJECTIVES: The objective of this study was to determine whether CCK and an opioid agonist could modulate the emotional experience of visual stimuli. MATERIALS AND METHODS: Thirteen healthy male volunteers viewed standardized pictures with either neutral or unpleasant content. Simultaneously, one of three treatments was administered in a randomized, double-blind crossover design: the CCKb receptor agonist pentagastrin (0.1 microg/kg), the mu-opioid receptor agonist remifentanil (0.0625 microg/kg), or saline. Self-ratings of the emotional experience of pictures and drugs were sampled together with psychological tests and recording of heart rate. RESULTS: Pentagastrin treatment increased the rating of unpleasantness for both neutral and unpleasant pictures, while it decreased the rating of pleasantness for the neutral pictures. These effects did not correlate with the degree of general unpleasantness induced by the drug. Remifentanil treatment increased the pleasantness for the neutral pictures. While pentagastrin treatment induced a heart rate increase, unpleasant pictures induced a heart rate decrease, and the magnitude of change in heart rate correlated positively for these conditions. CONCLUSIONS: This study shows that the CCK and the opioid system modulate how external stimuli are emotionally perceived, suggesting a possible involvement in affective disorders.

Effects of acute cholecystokinin infusion on hemispheric EEG asymmetry and coherence in healthy volunteers.

This study investigated the effects of continuous slow infusion of cholecystokinin tetrapeptide (CCK-4), a neuropeptide with panicogenic properties, on functional hemispheric differences, as indexed by quantitative electroencephalographic (EEG) asymmetry and coherence measures. Twenty-four adult volunteers (15 females and 9 males) were assigned to infusion with either placebo or CCK-4 in a randomized, double-blind, parallel-group design, with EEG being recorded before and during (10 and 40 min) a 60-min infusion period. No significant treatment differences were observed for absolute EEG power but, compared to placebo, CCK-4 infusion increased asymmetry and reduced coherence of slow-wave activity at midtemporal recording sites. These findings support the contention that functional imbalance of the temporal cortex, perhaps mediated by CCK-4, is involved in panic disorder (PD).

Acute cholecystokinin effects on event-related potentials in healthy volunteers.

This study investigated the effects of a continuous slow infusion of cholecystokinin tetrapeptide (CCK-4), a neuropeptide with panicogenic properties, on brain event-related potentials (ERPs) in healthy adults. Twenty-four volunteers, 15 females and 9 males, were assigned to infusion with either placebo or CCK-4 in a randomized, double-blind, parallel group design. ERPs, elicited within a standard auditory odd-ball paradigm requiring the counting of rare (20%) occurring 'deviant' tones interspersed among more frequent (80%) occurring 'standard' tones, were assessed once before infusion, and at 10 min and 40 min after the onset of infusion. Compared with the placebo, CCK-4 delayed the latencies of N100 and P200 components elicited by 'deviant' stimuli. No significant treatment differences were observed with respect to N200, P300b, mood or adverse symptoms. These preliminary findings suggest that CCK-4 may interfere with information processing relating to the selection of significant stimuli and as such, may be of relevance to mechanisms underlying panic disorder.