Psilocybin and Other Classic Psychedelics in Depression

Psychedelic drugs such as psilocybin and ketamine are returning to clinical research and intervention across several disorders including the treatment of depression. This chapter focusses on psychedelics that specifically target the 5-HT2A receptor such as psilocybin and DMT. These produce plasma-concentration related psychological effects such as hallucinations and out of body experiences, insightful and emotional breakthroughs as well as mystical-type experiences. When coupled with psychological support, effects can produce a rapid improvement in mood among people with depression that can last for months. In this chapter, we summarise the scientific studies to date that explore the use of psychedelics in depressed individuals, highlighting key clinical, psychological and neuroimaging features of psychedelics that may account for their therapeutic effects. These include alterations in brain entropy that disrupt fixed negative ruminations, a period of post-treatment increased cognitive flexibility, and changes in self-referential psychological processes. Finally, we propose that the brain mechanisms underlying the therapeutic effect of serotonergic psychedelics might be distinct from those underlying classical serotonin reuptake-blocking antidepressants.

Canalization and plasticity in psychopathology

This theoretical article revives a classical bridging construct, canalization, to describe a new model of a general factor of psychopathology. To achieve this, we have distinguished between two types of plasticity, an early one that we call 'TEMP' for 'Temperature or Entropy Mediated Plasticity', and another, we call 'canalization', which is close to Hebbian plasticity. These two forms of plasticity can be most easily distinguished by their relationship to 'precision' or inverse variance; TEMP relates to increased model variance or decreased precision, whereas the opposite is true for canalization. TEMP also subsumes increased learning rate, (Ising) temperature and entropy. Dictionary definitions of 'plasticity' describe it as the property of being easily shaped or molded; TEMP is the better match for this. Importantly, we propose that 'pathological' phenotypes develop via mechanisms of canalization or increased model precision, as a defensive response to adversity and associated distress or dysphoria. Our model states that canalization entrenches in psychopathology, narrowing the phenotypic state-space as the agent develops expertise in their pathology. We suggest that TEMP - combined with gently guiding psychological support - can counter canalization. We address questions of whether and when canalization is adaptive versus maladaptive, furnish our model with references to basic and human neuroscience, and offer concrete experiments and measures to test its main hypotheses and implications. This article is part of the Special Issue on "National Institutes of Health Psilocybin Research Speaker Series".

Ending the pain of children with severe epilepsy? An audit of the impact of medical cannabis in 10 patients

Background

Scientific and anecdotal evidence suggest that whole plant cannabis extracts are effective in reducing seizure frequency in individuals with a range of epileptic etiologies. We report a case series of 10 individuals using CBMPs in the UK to treat their conditions.

Methods

In this retrospective study, we report on patients (aged 2-48) with severe, intractable, childhood onset epilepsies using combined cannabinoid therapy. Carers of patients provided details through the charity ‘End our Pain’ and these data were subsequently analysed. Our primary objective was to assess changes in monthly seizure frequency pre and post initiation of CBMPs. We also report on previous and current AED, CBD:THC daily dose, quality of life and financial costs associated with CBMP private prescription. Change in monthly seizure frequency were assessed using a Wilcoxon Signed-ranks test.

Results

Of the 10 patients enrolled in the study there was an 97% mean reduction in monthly seizure frequency post initiation of CBMPs which was statistically significant (Z = 0, p < 0·01). We showed a reduction in AED use following initiation of CBMPs from a mean of 8 (±5·98) to 1 (±1·05). All patients were using either Bedrolite or Bedica (Bedrocan International) as their CBMP. Individual daily doses of THC ranged from 6·6mg – 26·5mg and for CBD, 200 mg – 550 mg. Average monthly cost of CBMP was £1816·20.

Interpretation

Our findings suggest a combination of CBD and THC based products are effective in reducing seizure frequency in a range of epileptic conditions. We highlight the inefficacy of the healthcare system in supporting these patients who bare great personal and financial burdens. We encourage specialist physicians and relevant bodies to permit greater ease of access of these medications to those patients where efficacy has been shown.

Effects of psilocybin therapy on personality structure

OBJECTIVE

To explore whether psilocybin with psychological support modulates personality parameters in patients suffering from treatment-resistant depression (TRD).

METHOD

Twenty patients with moderate or severe, unipolar, TRD received oral psilocybin (10 and 25 mg, one week apart) in a supportive setting. Personality was assessed at baseline and at 3-month follow-up using the Revised NEO Personality Inventory (NEO-PI-R), the subjective psilocybin experience with Altered State of Consciousness (ASC) scale, and depressive symptoms with QIDS-SR16.

RESULTS

Neuroticism scores significantly decreased while Extraversion increased following psilocybin therapy. These changes were in the direction of the normative NEO-PI-R data and were both predicted, in an exploratory analysis, by the degree of insightfulness experienced during the psilocybin session. Openness scores also significantly increased following psilocybin, whereas Conscientiousness showed trend-level increases, and Agreeableness did not change.

CONCLUSION

Our observation of changes in personality measures after psilocybin therapy was mostly consistent with reports of personality change in relation to conventional antidepressant treatment, although the pronounced increases in Extraversion and Openness might constitute an effect more specific to psychedelic therapy. This needs further exploration in future controlled studies, as do the brain mechanisms of postpsychedelic personality change.

Psilocybin with psychological support improves emotional face recognition in treatment-resistant depression

RATIONALE

Depressed patients robustly exhibit affective biases in emotional processing which are altered by SSRIs and predict clinical outcome.

OBJECTIVES

The objective of this study is to investigate whether psilocybin, recently shown to rapidly improve mood in treatment-resistant depression (TRD), alters patients' emotional processing biases.

METHODS

Seventeen patients with treatment-resistant depression completed a dynamic emotional face recognition task at baseline and 1 month later after two doses of psilocybin with psychological support. Sixteen controls completed the emotional recognition task over the same time frame but did not receive psilocybin.

RESULTS

We found evidence for a group × time interaction on speed of emotion recognition (p = .035). At baseline, patients were slower at recognising facial emotions compared with controls (p < .001). After psilocybin, this difference was remediated (p = .208). Emotion recognition was faster at follow-up compared with baseline in patients (p = .004, d = .876) but not controls (p = .263, d = .302). In patients, this change was significantly correlated with a reduction in anhedonia over the same time period (r = .640, p = .010).

CONCLUSIONS

Psilocybin with psychological support appears to improve processing of emotional faces in treatment-resistant depression, and this correlates with reduced anhedonia. Placebo-controlled studies are warranted to follow up these preliminary findings.

Psilocybin with psychological support for treatment-resistant depression: six-month follow-up

RATIONALE

Recent clinical trials are reporting marked improvements in mental health outcomes with psychedelic drug-assisted psychotherapy.

OBJECTIVES

Here, we report on safety and efficacy outcomes for up to 6 months in an open-label trial of psilocybin for treatment-resistant depression.

METHODS

Twenty patients (six females) with (mostly) severe, unipolar, treatment-resistant major depression received two oral doses of psilocybin (10 and 25 mg, 7 days apart) in a supportive setting. Depressive symptoms were assessed from 1 week to 6 months post-treatment, with the self-rated QIDS-SR16 as the primary outcome measure.

RESULTS

Treatment was generally well tolerated. Relative to baseline, marked reductions in depressive symptoms were observed for the first 5 weeks post-treatment (Cohen's d = 2.2 at week 1 and 2.3 at week 5, both p < 0.001); nine and four patients met the criteria for response and remission at week 5. Results remained positive at 3 and 6 months (Cohen's d = 1.5 and 1.4, respectively, both p < 0.001). No patients sought conventional antidepressant treatment within 5 weeks of psilocybin. Reductions in depressive symptoms at 5 weeks were predicted by the quality of the acute psychedelic experience.

CONCLUSIONS

Although limited conclusions can be drawn about treatment efficacy from open-label trials, tolerability was good, effect sizes large and symptom improvements appeared rapidly after just two psilocybin treatment sessions and remained significant 6 months post-treatment in a treatment-resistant cohort. Psilocybin represents a promising paradigm for unresponsive depression that warrants further research in double-blind randomised control trials.

Serotonin and brain function: a tale of two receptors

Previous attempts to identify a unified theory of brain serotonin function have largely failed to achieve consensus. In this present synthesis, we integrate previous perspectives with new and older data to create a novel bipartite model centred on the view that serotonin neurotransmission enhances two distinct adaptive responses to adversity, mediated in large part by its two most prevalent and researched brain receptors: the 5-HT1A and 5-HT2A receptors. We propose that passive coping (i.e. tolerating a source of stress) is mediated by postsynaptic 5-HT1AR signalling and characterised by stress moderation. Conversely, we argue that active coping (i.e. actively addressing a source of stress) is mediated by 5-HT2AR signalling and characterised by enhanced plasticity (defined as capacity for change). We propose that 5-HT1AR-mediated stress moderation may be the brain's default response to adversity but that an improved ability to change one's situation and/or relationship to it via 5-HT2AR-mediated plasticity may also be important - and increasingly so as the level of adversity reaches a critical point. We propose that the 5-HT1AR pathway is enhanced by conventional 5-HT reuptake blocking antidepressants such as the selective serotonin reuptake inhibitors (SSRIs), whereas the 5-HT2AR pathway is enhanced by 5-HT2AR-agonist psychedelics. This bipartite model purports to explain how different drugs (SSRIs and psychedelics) that modulate the serotonergic system in different ways, can achieve complementary adaptive and potentially therapeutic outcomes.

Effects of naltrexone are influenced by childhood adversity during negative emotional processing in addiction recovery

Naltrexone is an opioid receptor antagonist used in the management of alcohol dependence. Although the endogenous opioid system has been implicated in emotion regulation, the effects of mu-opioid receptor blockade on brain systems underlying negative emotional processing are not clear in addiction. Individuals meeting criteria for alcohol dependence alone (n=18, alcohol) and in combination with cocaine and/or opioid dependence (n=21, alcohol/drugs) and healthy individuals without a history of alcohol or drug dependence (n=21) were recruited. Participants were alcohol and drug abstinent before entered into this double-blind, placebo-controlled, randomized, crossover study. Functional magnetic resonance imaging was used to investigate brain response while viewing aversive and neutral images relative to baseline on 50 mg of naltrexone and placebo. We found that naltrexone modulated task-related activation in the medial prefrontal cortex and functional connectivity between the anterior cingulate cortex and the hippocampus as a function of childhood adversity (for aversive versus neutral images) in all groups. Furthermore, there was a group-by-treatment-by-condition interaction in the right amygdala, which was mainly driven by a normalization of response for aversive relative to neutral images under naltrexone in the alcohol/drugs group. We conclude that early childhood adversity is one environmental factor that influences pharmacological response to naltrexone. Pharmacotherapy with naltrexone may also have some ameliorative effects on negative emotional processing in combined alcohol and drug dependence, possibly due to alterations in endogenous opioid transmission or the kappa-opioid receptor antagonist actions of naltrexone.

Don't panic. A guide to tryptophan depletion with disorder-specific anxiety provocation

The 2002 paper "Does 5-HT restrain panic? A tryptophan depletion study in panic disorder patients recovered on paroxetine" by Bell and colleagues - reprinted in this issue of the Journal - reports on a study undertaken in the halcyon days of David Nutt's Psychopharmacology Unit at the University of Bristol, England. In this invited commentary authors of the original work discuss the impact of this paper on the field of acute tryptophan depletion research (especially in the field of clinical anxiety disorders) and the development of disorder-specific anxiogenic provocations over the past decade.

LSD-induced entropic brain activity predicts subsequent personality change

Personality is known to be relatively stable throughout adulthood. Nevertheless, it has been shown that major life events with high personal significance, including experiences engendered by psychedelic drugs, can have an enduring impact on some core facets of personality. In the present, balanced-order, placebo-controlled study, we investigated biological predictors of post-lysergic acid diethylamide (LSD) changes in personality. Nineteen healthy adults underwent resting state functional MRI scans under LSD (75µg, I.V.) and placebo (saline I.V.). The Revised NEO Personality Inventory (NEO-PI-R) was completed at screening and 2 weeks after LSD/placebo. Scanning sessions consisted of three 7.5-min eyes-closed resting-state scans, one of which involved music listening. A standardized preprocessing pipeline was used to extract measures of sample entropy, which characterizes the predictability of an fMRI time-series. Mixed-effects models were used to evaluate drug-induced shifts in brain entropy and their relationship with the observed increases in the personality trait openness at the 2-week follow-up. Overall, LSD had a pronounced global effect on brain entropy, increasing it in both sensory and hierarchically higher networks across multiple time scales. These shifts predicted enduring increases in trait openness. Moreover, the predictive power of the entropy increases was greatest for the music-listening scans and when "ego-dissolution" was reported during the acute experience. These results shed new light on how LSD-induced shifts in brain dynamics and concomitant subjective experience can be predictive of lasting changes in personality. Hum Brain Mapp 37:3203-3213, 2016. © 2016 Wiley Periodicals, Inc.

The paradoxical psychological effects of lysergic acid diethylamide (LSD)

BACKGROUND

Lysergic acid diethylamide (LSD) is a potent serotonergic hallucinogen or psychedelic that modulates consciousness in a marked and novel way. This study sought to examine the acute and mid-term psychological effects of LSD in a controlled study.

METHOD

A total of 20 healthy volunteers participated in this within-subjects study. Participants received LSD (75 µg, intravenously) on one occasion and placebo (saline, intravenously) on another, in a balanced order, with at least 2 weeks separating sessions. Acute subjective effects were measured using the Altered States of Consciousness questionnaire and the Psychotomimetic States Inventory (PSI). A measure of optimism (the Revised Life Orientation Test), the Revised NEO Personality Inventory, and the Peter's Delusions Inventory were issued at baseline and 2 weeks after each session.

RESULTS

LSD produced robust psychological effects; including heightened mood but also high scores on the PSI, an index of psychosis-like symptoms. Increased optimism and trait openness were observed 2 weeks after LSD (and not placebo) and there were no changes in delusional thinking.

CONCLUSIONS

The present findings reinforce the view that psychedelics elicit psychosis-like symptoms acutely yet improve psychological wellbeing in the mid to long term. It is proposed that acute alterations in mood are secondary to a more fundamental modulation in the quality of cognition, and that increased cognitive flexibility subsequent to serotonin 2A receptor (5-HT2AR) stimulation promotes emotional lability during intoxication and leaves a residue of 'loosened cognition' in the mid to long term that is conducive to improved psychological wellbeing.

LSD enhances the emotional response to music

RATIONALE

There is renewed interest in the therapeutic potential of psychedelic drugs such as lysergic acid diethylamide (LSD). LSD was used extensively in the 1950s and 1960s as an adjunct in psychotherapy, reportedly enhancing emotionality. Music is an effective tool to evoke and study emotion and is considered an important element in psychedelic-assisted psychotherapy; however, the hypothesis that psychedelics enhance the emotional response to music has yet to be investigated in a modern placebo-controlled study.

OBJECTIVES

The present study sought to test the hypothesis that music-evoked emotions are enhanced under LSD.

METHODS

Ten healthy volunteers listened to five different tracks of instrumental music during each of two study days, a placebo day followed by an LSD day, separated by 5-7 days. Subjective ratings were completed after each music track and included a visual analogue scale (VAS) and the nine-item Geneva Emotional Music Scale (GEMS-9).

RESULTS

Results demonstrated that the emotional response to music is enhanced by LSD, especially the emotions "wonder", "transcendence", "power" and "tenderness".

CONCLUSIONS

These findings reinforce the long-held assumption that psychedelics enhance music-evoked emotion, and provide tentative and indirect support for the notion that this effect can be harnessed in the context of psychedelic-assisted psychotherapy. Further research is required to test this link directly.

Progress in mind: focus on alcohol use disorders, an elsevier resource centre

Harmful use of alcohol is one of the top five risks for burden of disease globally and in Europe; in 2012, 3.3 million net deaths (approximately 6% of all global deaths) were attributable to this risk factor. It is also linked to the development of a wide spectrum of alcohol use disorders, ranging from mild manifestations to a severe disease known as alcohol dependence. Alcohol dependence is a progressive, chronic, and relapsing brain disease resulting from the prolonged effects of alcohol on the brain. Alcohol dependence imposes a significant societal burden, with indirect societal costs reaching up to 0.64% of European countries׳ annual gross domestic product. With these facts in mind, it is important to recognize and manage alcohol dependence. Although the biological mechanisms behind the development of alcohol dependence are not fully known, factors that have been shown to influence its development include genetic predisposition, psychological problems, and social interactions. Alcohol use has also been linked to the development of hypertension, liver cirrhosis, chronic pancreatitis, multiple types of cancer, and psychiatric comorbidities such as depression and anxiety disorders. With such severe effects on both individuals and society, it is important to recognize the characteristic signs and symptoms of alcohol dependence and explore new ways to better manage patients with this brain disease. Effective treatment approaches for alcohol dependence include biological, behavioral, and social components addressing the multiple aspects of this disease. Comprehensive, educational platforms in which to explore the many facets of this disease such as the Progress in Mind: Focus on Alcohol Use Disorders Resource Centre, will provide clinicians with the tools necessary for recognizing patients with alcohol dependence and managing their disease along with related comorbidities. Online Access: http://progressinmind.elsevierresource.com.

LSD enhances suggestibility in healthy volunteers

RATIONALE

Lysergic acid diethylamide (LSD) has a history of use as a psychotherapeutic aid in the treatment of mood disorders and addiction, and it was also explored as an enhancer of mind control.

OBJECTIVES

The present study sought to test the effect of LSD on suggestibility in a modern research study.

METHODS

Ten healthy volunteers were administered with intravenous (i.v.) LSD (40-80 μg) in a within-subject placebo-controlled design. Suggestibility and cued mental imagery were assessed using the Creative Imagination Scale (CIS) and a mental imagery test (MIT). CIS and MIT items were split into two versions (A and B), balanced for 'efficacy' (i.e. A ≈ B) and counterbalanced across conditions (i.e. 50 % completed version 'A' under LSD). The MIT and CIS were issued 110 and 140 min, respectively, post-infusion, corresponding with the peak drug effects.

RESULTS

Volunteers gave significantly higher ratings for the CIS (p = 0.018), but not the MIT (p = 0.11), after LSD than placebo. The magnitude of suggestibility enhancement under LSD was positively correlated with trait conscientiousness measured at baseline (p = 0.0005).

CONCLUSIONS

These results imply that the influence of suggestion is enhanced by LSD. Enhanced suggestibility under LSD may have implications for its use as an adjunct to psychotherapy, where suggestibility plays a major role. That cued imagery was unaffected by LSD implies that suggestions must be of a sufficient duration and level of detail to be enhanced by the drug. The results also imply that individuals with high trait conscientiousness are especially sensitive to the suggestibility-enhancing effects of LSD.

Psychiatry's next top model: cause for a re-think on drug models of psychosis and other psychiatric disorders

Despite the widespread application of drug modelling in psychiatric research, the relative value of different models has never been formally compared in the same analysis. Here we compared the effects of five drugs (cannabis, psilocybin, amphetamine, ketamine and alcohol) in relation to psychiatric symptoms in a two-part subjective analysis. In the first part, mental health professionals associated statements referring to specific experiences, for example 'I don't bother to get out of bed', to one or more psychiatric symptom clusters, for example depression and negative psychotic symptoms. This measured the specificity of an experience for a particular disorder. In the second part, individuals with personal experience with each of the above-listed drugs were asked how reliably each drug produced the experiences listed in part 1, both acutely and sub-acutely. Part 1 failed to find any experiences that were specific for negative or cognitive psychotic symptoms over depression. The best model of positive symptoms was psilocybin and the best models overall were the acute alcohol and amphetamine models of mania. These results challenge current assumptions about drug models and motivate further research on this understudied area.

The effects of elevated endogenous GABA levels on movement-related network oscillations

The EEG/MEG signal is generated primarily by the summation of the post-synaptic potentials of cortical principal cells. At a microcircuit level, these glutamatergic principal cells are reciprocally connected to GABAergic interneurons and cortical oscillations are thought to be dependent on the balance of excitation and inhibition between these cell types. To investigate the dependence of movement-related cortical oscillations on excitation-inhibition balance, we pharmacologically manipulated the GABA system using tiagabine, which blocks GABA Transporter 1(GAT-1), the GABA uptake transporter and increases endogenous GABA activity. In a blinded, placebo-controlled, crossover design, in 15 healthy participants we administered either 15mg of tiagabine or a placebo. We recorded whole-head magnetoencephalograms, while the participants performed a movement task, prior to, one hour post, three hour post and five hour post tiagabine ingestion. Using time-frequency analysis of beamformer source reconstructions, we quantified the baseline level of beta activity (15-30Hz), the post-movement beta rebound (PMBR), beta event-related desynchronisation (beta-ERD) and movement-related gamma synchronisation (MRGS) (60-90Hz). Our results demonstrated that tiagabine, and hence elevated endogenous GABA levels causes, an elevation of baseline beta power, enhanced beta-ERD and reduced PMBR, but no modulation of MRGS. Comparing our results to recent literature (Hall et al., 2011) we suggest that beta-ERD may be a GABAA receptor mediated process while PMBR may be GABAB receptor mediated.

A U-shaped relationship between systolic blood pressure and panic symptoms: the HUNT study

BACKGROUND

Previous studies on the relationship between blood pressure (BP) and psychological morbidity are conflicting. To resolve this confusing picture we examined the hypothesis that there is a non-linear relationship between panic and systolic BP (SBP) and explored the association of generalized anxiety symptoms with SBP. Method We used data from the population-based Nord-Trøndelag health study (HUNT) in which all 92 936 individuals aged ≥20 years residing in one Norwegian county were invited to participate. Panic was assessed using one item from the anxiety subscale of the Hospital Anxiety and Depression Scale (HADS) and generalized anxiety with the remaining six items of this subscale. SBP was the mean of two measurements by an automatic device.

RESULTS

A total of 64 871 respondents had SBP recorded (70%). Both unadjusted (n=61 408) and adjusted analyses provided evidence for a non-linear relationship between panic and SBP, represented by a U-shaped curve with a minimum prevalence of panic at around 140 mmHg. The relationship was strengthened after adjustment for confounders, with the quadratic term significantly associated with panic (p=0.03). Generalized anxiety symptoms were associated only with low SBP.

CONCLUSIONS

The U-shaped relationship between SBP and panic provides a unifying explanation for the separate strands of published literature in this area. The results support the hypothesis that high BP and panic disorder could share brainstem autonomic and serotonergic abnormalities. By contrast, generalized anxiety symptoms were more common only at lower BPs, suggesting that any biological link between panic and high BP does not extend to generalized anxiety.

BAP updated guidelines: evidence-based guidelines for the pharmacological management of substance abuse, harmful use, addiction and comorbidity: recommendations from BAP

The British Association for Psychopharmacology guidelines for the treatment of substance abuse, harmful use, addiction and comorbidity with psychiatric disorders primarily focus on their pharmacological management. They are based explicitly on the available evidence and presented as recommendations to aid clinical decision making for practitioners alongside a detailed review of the evidence. A consensus meeting, involving experts in the treatment of these disorders, reviewed key areas and considered the strength of the evidence and clinical implications. The guidelines were drawn up after feedback from participants. The guidelines primarily cover the pharmacological management of withdrawal, short- and long-term substitution, maintenance of abstinence and prevention of complications, where appropriate, for substance abuse or harmful use or addiction as well management in pregnancy, comorbidity with psychiatric disorders and in younger and older people.

ADHD matures: time for practitioners to do the same?

Attention deficit and hyperactivity disorder (ADHD) is not restricted to children. Abundant evidence from follow-up studies accumulated since the 1970s supports the concept of ADHD in adulthood. Genetic research points to a heritability of 76%, and neuroimaging studies have reported structural and functional brain abnormalities in patients with ADHD. Contrary to popular belief, ADHD is not a culturally bound disorder and has been described worldwide. ADHD has a cost for society, as adults with this disorder suffer from increased rates of unemployment and psychiatric comorbidity, including substance use disorders. Studies undertaken in forensic populations describe high rates of ADHD in these groups, particularly amongst young offenders. One of the main issues in the diagnosis of ADHD in the adult is the fact that most clinicians have not been educated to diagnose and treat ADHD. Effective pharmacological treatments for ADHD are available and should be prescribed for these patients. The National Institute for Health and Clinical Excellence (NICE) and the British Association for Psychopharmacology (BAP) guidelines established a benchmark for service development required to treat ADHD adequately in the adult population. However, the implementation of new services has been slow. More resources are needed to effectively assess and treat ADHD in the adult.

Central noradrenergic responsiveness to a clonidine challenge in Generalized Anxiety Disorder: a Single Photon Emission Computed Tomography study

Generalized Anxiety Disorder (GAD) may involve hypo-responsiveness of noradrenaline a2 receptors. To test this hypothesis, we used (99m)Tc-hexa-methyl-propylene-amine-oxime (HMPAO) Single Photon Emission Computed Tomography to measure regional cerebral perfusion in patients with untreated GAD, venlafaxine-treated patients and healthy controls during word generation before and after clonidine. Concurrent psychological and physiological measures supported noradrenergic hypofunction in GAD in some cases. A single-day split-dose technique was used. Images were processed using SPM5 (Institute of Neurology). Factorial analysis revealed no significant results. Exploratory analyses were done. Regional perfusion during verbal fluency differed by group pre-clonidine. Compared with healthy controls, patients with untreated GAD displayed increased perfusion in the left Broca's area and left occipitotemporal region. Treated GAD patients displayed increased cerebellar perfusion bilaterally. Clonidine was associated with different changes in cerebral perfusion in each group. Increases were seen in the right supra-marginal gyrus in healthy subjects, in the left pre-central gyrus in treated GAD patients and in the right cerebellum and middle frontal gyrus in untreated GAD patients. Despite these differences, the findings were not consistent with a noradrenergic hypo-responsiveness hypothesis, as the treated group showed a different pattern of response rather than a normalization of response.

Implications for psychedelic-assisted psychotherapy: functional magnetic resonance imaging study with psilocybin

BACKGROUND

Psilocybin is a classic psychedelic drug that has a history of use in psychotherapy. One of the rationales for its use was that it aids emotional insight by lowering psychological defences.

AIMS

To test the hypothesis that psilocybin facilitates access to personal memories and emotions by comparing subjective and neural responses to positive autobiographical memories under psilocybin and placebo.

METHOD

Ten healthy participants received two functional magnetic resonance imaging scans (2 mg intravenous psilocybin v. intravenous saline), separated by approximately 7 days, during which they viewed two different sets of 15 positive autobiographical memory cues. Participants viewed each cue for 6 s and then closed their eyes for 16 s and imagined re-experiencing the event. Activations during this recollection period were compared with an equivalent period of eyes-closed rest. We split the recollection period into an early phase (first 8 s) and a late phase (last 8 s) for analysis.

RESULTS

Robust activations to the memories were seen in limbic and striatal regions in the early phase and the medial prefrontal cortex in the late phase in both conditions (P<0.001, whole brain cluster correction), but there were additional visual and other sensory cortical activations in the late phase under psilocybin that were absent under placebo. Ratings of memory vividness and visual imagery were significantly higher after psilocybin (P<0.05) and there was a significant positive correlation between vividness and subjective well-being at follow-up (P<0.01).

CONCLUSIONS

Evidence that psilocybin enhances autobiographical recollection implies that it may be useful in psychotherapy either as a tool to facilitate the recall of salient memories or to reverse negative cognitive biases.

Opioids and anxiety

The opioid system plays a crucial role in the neural modulation of anxiety. The involvement of opioid ligands and receptors in physiological and dysfunctional forms of anxiety is supported by findings from a wide range of preclinical and clinical studies, including clinical trials, experimental research, and neuroimaging, genetic, and epidemiological data. In this review we provide a summary of studies from a variety of research disciplines to elucidate the role of the opioid system in the neurobiology of anxiety. First, we report data from preclinical studies using animal models to examine the modulatory role of central opioid system on defensive responses conducive to fear and anxiety. Second, we summarize the human literature providing evidence that clinical and experimental human studies are consistent with preclinical models. The implication of these data is that activation of the opioid system leads to anxiolytic responses both in healthy subjects and in patients suffering from anxiety disorders. The role of opioids in suppressing anxiety may serve as an adaptive mechanism, collocated in the general framework of opioid neurotransmission blunting acute negative and distressing affective responses.

A web-based survey on mephedrone

BACKGROUND

This study sought to collect information on the former legal-high 'mephedrone' using a web-based survey targeted at mephedrone users.

METHODS

The survey was advertised on websites frequented by drug users. Individuals were invited to complete the survey if they had taken mephedrone on at least one occasion in the past.

RESULTS

One thousand and six completed forms were received from declared users, making this the largest survey on mephedrone to date.

CONCLUSION

Results showed that mephedrone users consider its effects to compare best with those of MDMA, and while MDMA was considered marginally safer and its effects more pleasurable, mephedrone's appeal lay in its availability, low price and reliable purity.

A pilot study of the effectiveness of D-cycloserine during cue-exposure therapy in abstinent alcohol-dependent subjects

RATIONALE

Cue-exposure therapy (CET) has been advocated as a potentially effective treatment of addictive behaviours. Strategies that enhance learning may improve the outcome of CET. D-cycloserine (DCS), a partial N-methyl-D-aspartate receptor agonist, has been shown to facilitate extinction of learned fear in rats and augment exposure-based treatment in some anxiety disorders in man.

OBJECTIVE

This double-blind placebo-controlled pilot study used a cue-exposure paradigm, salient for an individual's alcohol drinking, to see if DCS would reduce cue-reactivity compared with placebo.

METHODS

Sixteen abstinent, alcohol-dependent individuals were randomised to receive either a single-dose (250 mg) DCS or placebo before CET sessions, separated by at least 1 week. Subjective responses were assessed using the Alcohol Urge Questionnaire (AUQ) and visual analogue scales. Cardiovascular responses were assessed using Finapres©.

RESULTS

The cue-exposure paradigm significantly increased craving assessed with the AUQ during the first session. In subsequent sessions, the degree of craving was reduced. However, no significant difference was seen between the DCS and placebo groups in any outcome measure. The variability of responses between individuals was great with more than half the groups reporting no or very small changes in AUQ scores.

CONCLUSION

This is the first human study to our knowledge to assess the efficacy of DCS in facilitating CET in alcohol dependence. The high proportion of subjects with little or no response to cue-exposure would make any effect of DCS very difficult to detect. It is important that future studies carefully consider the criteria for inclusion.

Autonomic dysregulation and the Window of Tolerance model of the effects of complex emotional trauma

This paper reviews the Window of Tolerance model of the long-term effects of the severe emotional trauma associated with childhood abuse, a model which can also be applied to adult trauma of sufficient severity to cause post-traumatic stress disorder, chronic dysthymic disorders and chronic anxiety disorders. Dysfunctional behaviours such as deliberate self-harm and substance abuse are seen as efforts to regulate an autonomic nervous system which is readily triggered into extreme states by reminders of the original traumatic events. While midbrain areas such as the periaqueductal gray mediate instant defence responses to traumatic events and their memory triggers it is proposed that ascending monoaminergic tracts are implicated in longer-term changes in mood and arousal. An imbalance of ascending dopaminergic tracts may drive rapid fluctuations in level of arousal and in the associated mood, drive and motivation. Animal models of depression frequently use traumatic experiences of pain, isolation or social defeat to induce changes in mesolimbic and mesocortical dopamine systems which may alter prefrontal cortical control of midbrain defence responses. A focus on the pharmacology of the Window of Tolerance could provide advances in drug treatments for promoting emotional regulation in those who are suffering from the chronic sequelae of traumatic experiences.

The role of central noradrenergic dysregulation in anxiety disorders: evidence from clinical studies

The nature of the noradrenergic dysregulation in clinical anxiety disorders remains unclear. In panic disorder, the predominant view has been that central noradrenergic neuronal networks and/or the sympathetic nervous system was normal in patients at rest, but hyper-reactive to specific stimuli, for example carbon dioxide. These ideas have been extended to other anxiety disorders, which share with panic disorder characteristic subjective anxiety and physiological symptoms of excess sympathetic activity. For example, Generalized Anxiety Disorder is characterized by chronic free-floating anxiety, muscle tension, palpitation and insomnia. It has been proposed that there is chronic central hypersecretion of noradrenaline in Generalized Anxiety Disorder, with consequent hyporesponsiveness of central post-synaptic receptors. With regards to other disorders, it has been suggested that there is noradrenergic involvement or derangement, but a more specific hypothesis has not been enunciated. This paper reviews the evidence for noradrenergic dysfunction in anxiety disorders, derived from indirect measures of noradrenergic function in clinical populations.

Noradrenergic function in generalized anxiety disorder: impact of treatment with venlafaxine on the physiological and psychological responses to clonidine challenge

Serotonin and noradrenaline reuptake inhibitor (SNRI) antidepressants have evidence of efficacy in the treatment of generalized anxiety disorder (GAD); however, it is not clear whether there is an advantage over selective serotonin reuptake inhibitor (SSRI) medicines and there is limited evidence for noradrenergic dysfunction in GAD. We tested whether a dysfunctional alpha-2 adrenoceptor system is present in patients with GAD and the effects of SNRI treatment on this system. The method used was an infusion of clonidine (a selective alpha-2 adrenergic receptor agonist) on psychological and physiological outcomes in three subject groups: 10 untreated GAD patients, five SNRI-treated GAD patients and seven normal controls. The clonidine challenge elicited sedation, a rise in growth hormone, decrease in blood pressure, decline in saccadic eye movement (SEM) variables, and improvement in verbal fluency as anticipated in the 22 subjects examined. Lower cortisol levels were found in controls and higher blood pressure readings in GAD-treated subjects, as well as evidence that GAD-treated subjects had SEMs that were intermediate between control and GAD subjects' scores and have less clonidine-induced sedation. The implications of these findings with reference to the study hypothesis in this small study are discussed.

A psychopharmacological treatment algorithm for generalised anxiety disorder (GAD)

Generalised anxiety disorder (GAD) is defined as excessive and uncontrollable worry and anxiety about everyday life situations. It is a chronic disorder, and is associated with substantial somatisation, high rates of comorbid depression and other anxiety disorders, and significant disability. The evidence base for pharmacotherapy and psychotherapy has continued to grow, and a wide range of drug choices for GAD now exists. Current guidelines for GAD generally restrict themselves to presentation of the evidence for various treatments, which, as a result, generally do not offer detailed discussion or recommendation of strategies beyond the first level of treatment, or take into account the individual circumstances of the patient. Thus, there is a lack of algorithm-based treatment guidelines for GAD. Our aim is, therefore, to present an algorithm for the psychopharmacologic management of GAD, intended for all clinicians who treat patients with GAD, where issues of pharmacotherapy are under consideration. We also hope that these GAD algorithms and other guidelines can help to identify high-priority areas that need further study. In this algorithm, we provide a sequenced approach to the pharmacotherapy of GAD, taking into account salient symptomatology and comorbidity, levels of evidence and extent of response. Special issues, including comorbidity, insomnia, suicidality, substance abuse, treatment adherence, pregnancy and lactation, cross-cultural issues, use of medication in the elderly, psychosocial treatment and dosing issues are also addressed.

British Association for Psychopharmacology consensus statement on evidence-based treatment of insomnia, parasomnias and circadian rhythm disorders

Sleep disorders are common in the general population and even more so in clinical practice, yet are relatively poorly understood by doctors and other health care practitioners. These British Association for Psychopharmacology guidelines are designed to address this problem by providing an accessible up-to-date and evidence-based outline of the major issues, especially those relating to reliable diagnosis and appropriate treatment. A consensus meeting was held in London in May 2009. Those invited to attend included BAP members, representative clinicians with a strong interest in sleep disorders and recognized experts and advocates in the field, including a representative from mainland Europe and the USA. Presenters were asked to provide a review of the literature and identification of the standard of evidence in their area, with an emphasis on meta-analyses, systematic reviews and randomized controlled trials where available, plus updates on current clinical practice. Each presentation was followed by discussion, aimed to reach consensus where the evidence and/or clinical experience was considered adequate or otherwise to flag the area as a direction for future research. A draft of the proceedings was then circulated to all participants for comment. Key subsequent publications were added by the writer and speakers at draft stage. All comments were incorporated as far as possible in the final document, which represents the views of all participants although the authors take final responsibility for the document.

The effects of single dose anxiolytic medication on the CO2 models of anxiety: differentiation of subjective and objective measures

This was a double blind, placebo-controlled, 4-way cross-over study in 12 healthy volunteer subjects of the acute effects of three drugs each of which are used in the clinic to treat some forms of anxiety: propranolol 40 mg, hydroxyzine 25 mg, flupentixol 0.5 mg and placebo. Each test session consisted of inhalation of air for 20 min, 10-min rest, inhalation of CO2 7.5% for 20 min, 10-min rest, followed by a single vital capacity inhalation of 35% CO2. The CO2 7.5% was administered at peak drug effect. Subjective effects were measured using Visual Analogue Scales (VAS), the Panic Symptom Inventory and the Generalised Anxiety Disorder Assessment inventory. Twelve subjects participated (eight men), with a mean age of 25.9 years. The expected subjective effects of CO2 were seen and these were significantly different from effects of peak air. However, there were no statistically significant differences between the drugs or between drugs and placebo, indeed there was a trend for some VAS anxiety scores to be higher than placebo in the drug groups. There were some significant differences in cardiovascular responses to CO2, with propranolol significantly decreasing heart rate and flupentixol increasing blood pressure when compared with placebo. The lack of subjective anxiolytic actions of the three drugs contrasts with our previous findings with acute benzodiazepines and chronic selective serotonin reuptake inhibitor administration. It may be that prolonged treatment with these agents would be required to show anxiolytic effects, although it may also be that their efficacy is insufficient to be demonstrated in this model. The lack of anxiolytic actions of propranolol, despite a significant reduction in heart rate, is a further support for a central action of CO2 to produce anxiety.

Voluntary exercise alters GABA(A) receptor subunit and glutamic acid decarboxylase-67 gene expression in the rat forebrain

Voluntary exercise improves stress coping and lowers anxiety. Because of the role of GABA in these processes, we investigated changes in the central GABAergic system in rats with free access to a running wheel for 4 weeks. The control animals had no access to a running wheel. Using insitu hybridisation histochemistry, we studied changes in gene expression of various GABA(A) receptor subunits as well as the GABA-synthesising enzyme glutamic acid decarboxylase-67 (GAD67) in the forebrain. There were region-specific decreases in alpha2, beta3 and gamma2 subunit mRNA expression and region-specific increases in beta1 subunit expression. The alpha5 and delta subunits, in the forebrain specifically associated with extrasynaptic GABA(A) receptors in the hippocampus, showed differential increases in expression levels. Expression of GAD67 mRNA was increased in many forebrain regions including all hippocampal cell layers, peri-paraventricular nucleus, bed nucleus stria terminalis, nucleus accumbens core and motor cortex, suggesting that long-term voluntary exercise enhances forebrain GABA synthesis capacity but in a region-specific manner. Thus, regular performance of exercise results in extensive changes in the forebrain GABAergic system that may be implicated in the changes in stress sensitivity and emotionality observed in exercising subjects.

Anxiety--bridging the heart/mind divide

Although the complimentary roles of heart and brain in anxiety have been recognised for centuries, the precise contribution of each and more importantly perhaps their interplay has proved difficult to describe. Recent data from human brain imaging and cardiovascular physiology studies are beginning to delineate the mechanistic pathways of anxiety disorders in general and panic in particular. Evidence for a dysfunction of brain gamma-amino butyric acid-A and serotonin (5HT) systems in both panic and cardiovascular regulation is reviewed along with new evidence for altered sympathetic nervous system activity in the heart and periphery. Testable hypotheses and research ideas are suggested.

Dopaminergic challenges in social anxiety disorder: evidence for dopamine D3 desensitisation following successful treatment with serotonergic antidepressants

Serotonergic antidepressants (SSRIs) are first-line treatments for social anxiety disorder [SAnD], though there is evidence of dopaminergic system dysfunction. Twenty subjects with DSM-IV SAnD, untreated (n = 10) and SSRI-remitted DSM-IV SAnD (n = 10), were administered a single dose of 1) a dopamine agonist (pramipexole 0.5 mg) and 2) a dopamine antagonist (sulpiride 400 mg), followed by anxiogenic challenges (verbal tasks and autobiographical scripts) in a double-blind crossover design, the two test days being one week apart. Anxiety symptoms were measured by self-reported changes in Visual Analogue Scales, specific SAnD scales and anxiety questionnaires. Plasma levels of prolactin were obtained. Untreated SAnD subjects experienced significant increases in anxiety symptoms following behavioural challenges after either sulpiride or pramipexole. Following remission with SSRIs, the socially anxiogenic effect of behavioural provocation was significantly attenuated under pramipexole, whereas under sulpiride effects remained significantly elevated. There appears to be instability of the dopamine system under behavioural stress in social anxiety subjects that is only partly rectified by successful treatment with an SSRI, which may induce a desensitisation of postsynaptic dopamine D(3) receptors.

Hypothermic responses to infection are inhibited by alpha2-adrenoceptor agonists with possible clinical implications

BACKGROUND

alpha(2)-Adrenoceptor agonists are currently used as primary sedative agents in high dependency patients who are at high risk of sepsis. Clinical surveillance of such patients relies in part on their ability to mount appropriate responses to infection, in particular thermal responses. Thermoregulatory responses to infection are well studied in the rat and in this species, and humans, infection can induce febrile, hypothermic, or mixed hypothermic and febrile responses. The involvement of noradrenergic systems in thermal responses to infection prompted the hypothesis that ligands that act on adrenoceptors may interfere with the normal thermal responses to infection.

METHODS

In this study on rats, the effect of infusion of the selective alpha(2)-agonist, mivazerol, on hypothermic and plasma corticosterone responses induced by bacterial lipopolysaccharide (LPS) was investigated.

RESULTS

Clinically effective doses of mivazerol (4.8 and 10 microg kg(-1) h(-1)) had no effect on body temperature alone. However, mivazerol significantly inhibited the typical thermoregulatory response to bacterial LPS in a dose-dependent manner. This effect was mimicked by the selective alpha(2)-agonist, UK14304-18 (6 microg kg(-1) h(-1)), and antagonized by the alpha(2)-antagonist, RX811059A (7 microg kg(-1) h(-1)). The alpha(2)-ligands had no effect on basal or LPS-induced corticosterone levels.

CONCLUSIONS

These data suggest that early thermoregulatory responses to infection can be selectively antagonized by ligands that activate alpha(2)-adrenoreceptors. High dependency patients receiving alpha(2)-adrenoceptor agonists may not be capable of mounting a normal thermal response to infecting organisms and clinical monitoring using core temperature to detect infection may therefore be unreliable in these vulnerable patients.

Characterisation of the effects of caffeine on sleep in the rat: a potential model of sleep disruption

Caffeine is known to disrupt sleep and its administration to human subjects has been used to model sleep disruption. We previously showed that its effects on sleep onset latency are comparable between rats and humans. This study evaluated the potential use of caffeine as a model of sleep disruption in the rat, by assessing its effects on sleep architecture and electroencephalogram (EEG) frequency spectrum, and using sleep-promoting drugs to reverse these effects. Rats were implanted with radiotelemetry devices for body temperature, EEG, electromyogram and locomotor activity. Following recovery, animals were dosed with caffeine (10 mg/kg) alone or in combination with zolpidem (10 mg/kg) or trazodone (20 mg/kg). Sleep was scored for the subsequent 12 h using automated analysis software. Caffeine dose-dependently disrupted sleep: it increased WAKE time, decreased NREM (non-REM) sleep time and NREM bout duration (but not bout number), and decreased delta activity in NREM sleep. It also dose-dependently increased locomotor activity and body temperature. When given alone, zolpidem suppressed REM whilst trazodone increased NREM sleep time at the expense of WAKE, increased NREM bout duration, increased delta activity in NREM sleep and reduced body temperature. In combination, zolpidem attenuated caffeine's effects on WAKE, whilst trazodone attenuated its effects on NREM sleep, NREM bout duration, delta activity, body temperature and locomotor activity. Caffeine administration produced many of the signs of insomnia that were improved by two of its most successful current treatments. This model may therefore be useful in the study of new drugs for the treatment of sleep disturbance.

Effects on sleep stages and microarchitecture of caffeine and its combination with zolpidem or trazodone in healthy volunteers

Caffeine is the world's most popular stimulant and is known to disrupt sleep. Administration of caffeine can therefore be used in healthy volunteers to mimic the effects of insomnia and thus to test the hypnotic effects of medication. This study assessed the effects of caffeine on sleep architecture and electroencephalography (EEG) spectrum alone and in combination with two different sleep-promoting medications. Home polysomnography was performed in 12 healthy male volunteers in a double-blind study whereby subjects received placebo, caffeine (150 mg), caffeine plus zolpidem (10 mg) and caffeine plus trazodone (100 mg) at bedtime in a randomised crossover design. In addition to delaying sleep onset, caffeine decreased total sleep time (TST), sleep efficiency (SE) and stage 2 sleep without significantly altering wake after sleep onset or the number of awakenings. Zolpidem attenuated the caffeine-induced decrease in SE and increased spindle density in the caffeine plus zolpidem combination compared with placebo. Trazodone attenuated the decrease in SE and TST, and it also increased stage 3 sleep, decreased the number of awakenings and decreased the spindle density. No significant changes in rapid eye movement (REM) sleep were observed, neither was any significant alteration in slow wave activity nor other EEG spectral measures, although the direction of change was similar to that previously reported for caffeine and appeared to 'normalise' after trazodone. These data suggest that caffeine mimics some, but not all of the sleep disruption seen in insomnia and that its disruptive effects are differentially attenuated by the actions of sleep-promoting compounds with distinct mechanisms of action.

That warm fuzzy feeling: brain serotonergic neurons and the regulation of emotion

Whether lying on the beach in the midday sun on a Caribbean island, grabbing a few minutes in the sauna or spa after work, or sitting in a hot bath or Jacuzzi in the evening, we often associate feeling warm with a sense of relaxation and well-being. Even 'working up a good sweat', exercising or performing manual labour in the garden can have its rewards. Although we take these feelings for granted, convergent lines of evidence suggest that sensations of 'warmth' may alter neural circuits controlling cognitive function and mood, including serotonergic circuits, in addition to those directly involved in thermoregulatory cooling. One mechanism through which sensations of warmth may modulate neural circuits controlling cognitive function and mood is the activation of temperature-activated transient receptor potential (TRP) ion channels, including TRPv3 and TRPv4 which are active in the non-noxious thermal range, 27-42 degrees C, and subsequent activation of a subpopulation of brainstem serotonergic neurons. In this article, we explore the hypothesis that a subpopulation of serotonergic neurons are thermosensitive and form part of a thermoafferent pathway regulating physiology and behaviour. We also propose the novel hypothesis that dysregulation of this thermosensitive population of serotonergic neurons plays an important role in stress-related neuropsychiatric disorders, including anxiety and affective disorders.

Current and former ecstasy users report different sleep to matched controls: a web-based questionnaire study

This study sought to test the association between ecstasy-use and abnormal sleep. An anonymous web-based questionnaire containing questions on drug use and sleep was completed by 1035 individuals. From this large sample, a group of 89 ecstasy users were found who reported very little use of other drugs. This "ecstasy-only" group was further divided into two groups of 31 current users and 58 abstinent users. The subjective sleep of current and former ecstasy-only users was compared with that of matched controls. Patients were asked to rate their sleep according to: 1) sleep quality, 2) sleep latency, 3) night time awakenings and 4) total sleep time. Current ecstasy-only users reported significantly worse sleep quality (P < 0.05) and a greater total sleep time (P < 0.001) than controls. It was inferred that these differences might be due to recovery from the acute effects of the drug. Abstinent ecstasy-only users reported significantly more nighttime awakenings than controls (P < 0.01). These subjective findings are in agreement with the objective findings of previous studies showing persistent sleep abnormalities in ecstasy users.

A comparison of the effects of a subtype selective and non-selective benzodiazepine receptor agonist in two CO(2) models of experimental human anxiety

Studies in human volunteers that can demonstrate proof of concept are attractive in that possible mechanisms and potential new drug treatments can be examined. We have been developing models of anxiety disorders using the inhalation of 7.5% CO(2) for 20 min to model generalised anxiety disorder, as well as using the previously reported 35% CO(2) as a model for panic anxiety. In a double-blind, placebo-controlled, three-way crossover study in 12 healthy volunteer subjects, we compared a full agonist at the benzodiazepine receptor that binds to four alpha-subtypes of the receptor (alpha-1,-2,-3,-5) (alprazolam 1 mg), with zolpidem (5 mg), an agonist selective for the alpha-1 subtype of the gamma amino butyric acid-receptor subtype A (GABA-A) receptor, which is a widely used hypnotic drug. Compared with placebo, both drugs significantly attenuated peak CO(2)-induced changes in subjective feelings after the inhalation of 7.5% CO(2) for 20 min. However, there were fewer significant differences after a single vital capacity inhalation of 35% CO(2), where zolpidem was less efficacious than alprazolam at reducing CO(2)-induced symptoms. In conclusion, our results show that zolpidem shows some anxiolytic efficacy in the 7.5% CO(2) model, similar to alprazolam, and this is the first report of such an effect of zolpidem in a model of anxiety. These and other studies of benzodiazepines in clinical and volunteer studies suggest a definite role of the GABA-A receptor in CO(2)-induced anxiety, and it would be of interest to examine other GABA-A receptor subtype selective drugs, which are now in early phase clinical studies and are showing selective efficacy in pharmacodynamic studies.