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The neurobiological basis of panic disorder has not been clearly established, although a role for serotonin (5-HT) has been postulated. It is clear that drugs which increase 5-HT neurotransmission are effective in treating the condition but how they do so remains a point of debate. The aim of this study was to determine if lowering brain serotonin activity using the technique of tryptophan depletion provoked a short-term relapse of panic symptoms in patients with panic disorder who had responded to drug treatment. Fourteen patients with panic disorder who had responded to treatment with the selective serotonin reuptake inhibitor (SSRI) paroxetine received a tryptophan-free amino acid drink on one occasion and a control drink on the other in a double-blind crossover design. In addition, they received an infusion of flumazenil (used as a pharmacological challenge) and placebo on each day. The tryptophan depleted drink produced an 87% reduction in plasma tryptophan concentration. Flumazenil produced a panic attack (defined by changes in the panic inventory) in seven out of 14 patients when tryptophan depleted and one out of 14 on the control day (p < 0.02). Three patients also experienced temporary depressive symptoms when tryptophan depleted, with no mood changes being seen on the control days. We conclude that rapid lowering of brain serotonin function can allow the precipitation of panic symptoms in response to flumazenil in panic disorder patients who have responded to treatment with an SSRI. This implies that in panic disorder increased 5-HT availability is important in maintaining the response to SSRIs.

The psychometric tools used for the assessment of generalized anxiety disorder (GAD) either do not conform to the current concept of the condition or have important limitations. We aimed to develop and validate a new questionnaire for the assessment of symptom profile and severity of GAD. An original pool of potential scale items was subjected to a series of studies in non-clinical and clinical populations, in order to determine the final composition of the scale. The psychometric properties of the new scale, the Generalized Anxiety Disorder Inventory (GADI), were evaluated using a factor analytic model suitable for ordinal data and the Graded Response Model. The precision of measurement of the GADI was quantified through the item information functions.A total of 197 outpatients and 522 non-clinical subjects participated in four studies and completed the GADI. The final 18-item scale was derived from an original pool of 30 potential items. The GADI showed good reliability, convergent and divergent validity. The scale comprises three factors, relating to cognitive, somatic and sleep symptoms. It accurately distinguished GAD patients from non-patient controls. The cognitive factor also distinguished GAD from other anxiety disorders and depression. The GADI is a useful tool in the assessment of the breadth of symptoms and the severity of generalized anxiety disorder in clinical settings.

Pagoclone is a cyclopyrrolone that is believed to act as a partial agonist at the gamma-aminobutyric acid (GABA)-A/benzodiazepine (BDZ) receptor. In theory, such partial agonists should be anxiolytic but lack the adverse side-effects of sedation, tolerance and withdrawal associated with full GABA-A/BDZ agonists. The objective of the randomized double-blind crossover study was to assess whether pagoclone was an effective anti-panic agent and also to assess its side-effect profile. Patients recruited had a diagnosis of Panic Disorder (DSM-IV) with at least one panic attack per week. Following a 2-week screening period, patients entered a 6-week trial consisting of two 2-week treatment periods, each followed by a 1-week washout. Patients were randomly assigned to receive either pagoclone 0.1 mg t.d.s. or placebo on their first treatment period and the converse on their second. The primary measure was daily panic attack dairy. Fourteen patients completed the study, the mean number of panic attacks during screening was 5.8+/-0.8 (SEM), this fell to 3.6+/-0.5 during treatment with pagoclone (p = 0.05) and 4.3+/-0.8 with placebo (p = 0.14). There was no significant difference on direct comparison of pagoclone with placebo or in any of the secondary measures (including Rickels withdrawal scale) or the adverse event profiles. The study provides preliminary evidence that pagoclone has anxiolytic properties in the absence of typical BDZ side-effects. This is consistent with its theoretical mode of action as a partial agonist at the GABA(A)/BDZ receptor.

IntroductionMost individuals treated for heroin use disorder receive opioid agonist treatment (OAT)(methadone or buprenorphine). However, OAT is associated with high attrition and persistent, occasional heroin use. There is some evidence for the effectiveness of contingency management (CM), a behavioural intervention involving modest financial incentives, in encouraging drug abstinence when applied adjunctively with OAT. UK drug services have a minimal track record of applying CM and limited resources to implement it. We assessed a CM intervention pragmatically adapted for ease of implementation in UK drug services to promote heroin abstinence among individuals receiving OAT.DesignCluster randomised controlled trial.Setting and participants552 adults with heroin use disorder (target 660) enrolled from 34 clusters (drug treatment clinics) in England between November 2012 and October 2015.InterventionsClusters were randomly allocated 1:1:1 to OAT plus 12× weekly appointments with: (1) CM targeted at opiate abstinence at appointments (CM Abstinence); (2) CM targeted at on-time attendance at appointments (CM Attendance); or (3) no CM (treatment as usual; TAU). Modifications included monitoring behaviour weekly and fixed incentives schedule.MeasurementsPrimary outcome: heroin abstinence measured by heroin-free urines (weeks 9–12). Secondary outcomes: heroin abstinence 12 weeks after discontinuation of CM (weeks 21–24); attendance; self-reported drug use, physical and mental health.ResultsCM Attendance was superior to TAU in encouraging heroin abstinence. Odds of a heroin-negative urine in weeks 9–12 was statistically significantly greater in CM Attendance compared with TAU (OR=2.1; 95% CI 1.1 to 3.9; p=0.030). CM Abstinence was not superior to TAU (OR=1.6; 95% CI 0.9 to 3.0; p=0.146) or CM Attendance (OR=1.3; 95% CI 0.7 to 2.4; p=0.438) (not statistically significant differences). Reductions in heroin use were not sustained at 21–24 weeks. No differences between groups in self-reported heroin use.ConclusionsA pragmatically adapted CM intervention for routine use in UK drug services was moderately effective in encouraging heroin abstinence compared with no CM only when targeted at attendance. CM targeted at abstinence was not effective.Trial registration numberISRCTN 01591254.