From hallucinations to synaesthesia: a circular inference account of unimodal and multimodal erroneous percepts in clinical and drug-induced psychosis

Psychedelics are known to distort perception and induce visual and multimodal hallucinations as well as synaesthesia. This is in contradiction with the high prevalence of distressing voices in schizophrenia. Here we introduce a unifying account of unimodal and multimodal erroneous percepts based on circular inference. We show that amplification of top-down predictions (descending loops) leads to an excessive reliance on priors and aberrant levels of integration of the sensory representations, resulting in crossmodal percepts and stronger illusions. By contrast, amplification of bottom-up information (ascending loops) results in overinterpretation of unreliable sensory inputs and high levels of segregation between sensory modalities, bringing about unimodal hallucinations and reduced vulnerability to illusions. We delineate a canonical microcircuit in which layer-specific inhibition controls the propagation of information across hierarchical levels: inhibitory interneurons in the deep layers exert control over priors, removing descending loops. Conversely, inhibition in the supragranular layers counterbalances the effects of the ascending loops. Overall, we put forward a multiscale and transnosographic account of psychosis with important theoretical, conceptual and clinical implications.

Methylphenidate-induced psychosis in a young antipsychotic-naïve female patient

Methylphenidate (MPD) is commonly prescribed for patients with Attention Deficit/Hyperactivity Disorder (ADHD). Although used off-label, MPD forms part of complex and multifactorial treatment regimen for narcolepsy and hypersomnia, together with including behavioural interventions. The drug is sometimes also prescribed off-label to subjects with other mental illness or somatic condition to improve intellectual outcome, ease fatigue or enhance the ability to concentrate. Common side effects include headache, insomnia, decreased appetite and hypertension. Concurrently, clinicians should be aware of relatively rare but potentially threatening adverse effects including agitation and psychotic symptoms. Several case reports regarding MPD-induced psychosis have been published, but most of them regard children or teenagers (1) and much less is known about drug-induced psychosis in adults (2). In this article, we present a case report of MPD-induced psychosis in a 31-year-old, antipsychotic-naïve patient. Careful evaluation including clinical examination, medical and family history and possible early signs of psychosis is recommended each time before MPD treatment will be initiated.

Herbal High: Substance-Induced Psychosis after Consumption of Seeds of the Hawaiian Baby Woodrose

Seeds of the Hawaiian Baby Woodrose (HBWR, Argyreia nervosa) are known as “legal or herbal highs” and can be easily purchased online in Germany. They contain various ergot alkaloids, including lysergic acid amide (LSA), which is chemically related to lysergic acid diethylamide (LSD). Pharmacological data are limited but suggest that LSA-concentration in HBWR seeds is highly variable, and that adverse psychiatric and somatic effects are not related to LSA-dosage. Anecdotal, mostly cross-sectional clinical case reports describe spontaneous remission of intoxication-related somatic and psychiatric symptoms as well as intoxication-related death. Treatment recommendations for LSA-induced psychiatric syndromes are not available. We report here on the clinical course and treatment of a drug-induced psychosis after consumption of HBWR seeds. The adolescent had consumed HBWR seeds once before without suffering any negative effects.

Oedipism: An unusual case of auto-enucleation including mechanism of avulsion

Introduction: Self-inflicted enucleation, also known as auto-enucleation (AE) or Oedipism, is an uncommon and severe form of ocular injury which presents as an ophthalmic and psychiatric emergency. Usually known to occur with untreated psychosis, this case is a rare report which demonstrates AE as a result of a subsequently diagnosed drug induced psychosis. We report the clinical presentation, management and for the first time a detailed speculative account about the mechanism of AE, based on our clinicopathologic findings. Case report: A 53-year old Afro-Caribbean patient was arrested following an altercation and was incarcerated awaiting arraignment. The patient had no previous psychiatric history but tested positive for cannabis, opiates and cocaine as well as admitting to illicit drug use in the community. Whilst in custody, the patient self-enucleated his right eye. The patient declined consent to eye examination and was subsequently admitted under section 2 of the Mental Health Act. After full work-up including Goldmann visual fields and magnetic resonance imaging, he underwent right orbital exploration under anesthetic where AE was confirmed whilst the left eye showed evidence of attempted enucleation. The residual tenons and conjunctiva was subsequently repaired without placement of an orbital implant in the right orbit. The globe was sent for histology which revealed clues to the potential mechanism of auto-enucleation. Conclusion: This case is unique as it offers an alternative presentation to those most commonly reported in the current literature, highlights the sparsity of literature detailing the mechanism of AE and stimulates discussion around various potential systemic etiological differential diagnoses, management strategies and complications of AE.

A Case of Ciprofloxacin-induced Acute Psychosis After Aortic Dissection Surgery

Ciprofloxacin is widely used in general infected population, including patients with aortic dissection. Ciprofloxacin-mediated neurotoxicity has been observed in few reports, and some studies found ciprofloxacin may increase the incidence of aortic dissection or aortic aneurysm rupture. We report here a case of ciprofloxacin-induced acute psychosis after Sun’s total arch replacement and cardiopulmonary resuscitation. Based on the published literature and FDA hypothesis, we suggest that ciprofloxacin should be used cautiously in patients after aortic dissection surgery in the risk of drug-induced psychosis and residual dilated aortic rupture.

Isoniazid Induced Psychosis: A Case Report

Psychosis is a state of altered behaviour and mentation and it is not common in children. Isoniazid is a commonly used drug in the treatment and prophylaxis of tuberculosis. It may cause psychosis if overdosed but rarely with usual recommended doses. We report a case of drug induced psychosis secondary to isoniazid intake in a seven years old boy, who exhibited psychotic features about 10 days after the commencement of anti-TB combination drugs (Directly Observed Treatment Shortcourse) containing Isoniazid. This patient had no past medical or family history of mental illness. Drug induced psychosis was a possibility, and the responsible drug (isoniazid) was stopped. He improved following the withdrawal of isoniazid. Isoniazid psychosis is a major complication as iatrogenic psychiatric complications can greatly impact the patients’ quality of life, which if recognised early can be effectively treated.

Transition of Substance-Induced, Brief, and Atypical Psychoses to Schizophrenia: A Systematic Review and Meta-analysis

Some people who experience substance-induced psychosis later develop an enduring psychotic disorder such as schizophrenia. This study examines the proportion of people with substance-induced psychoses who transition to schizophrenia, compares this to other brief and atypical psychoses, and examines moderators of this risk. A search of MEDLINE, PsychINFO, and Embase identified 50 eligible studies, providing 79 estimates of transition to schizophrenia among 40 783 people, including 25 studies providing 43 substance-specific estimates in 34 244 people. The pooled proportion of transition from substance-induced psychosis to schizophrenia was 25% (95% CI 18%–35%), compared with 36% (95% CI 30%–43%) for brief, atypical and not otherwise specified psychoses. Type of substance was the primary predictor of transition from drug-induced psychosis to schizophrenia, with highest rates associated with cannabis (6 studies, 34%, CI 25%–46%), hallucinogens (3 studies, 26%, CI 14%–43%) and amphetamines (5 studies, 22%, CI 14%–34%). Lower rates were reported for opioid (12%), alcohol (10%) and sedative (9%) induced psychoses. Transition rates were slightly lower in older cohorts but were not affected by sex, country of the study, hospital or community location, urban or rural setting, diagnostic methods, or duration of follow-up. Substance-induced psychoses associated with cannabis, hallucinogens, and amphetamines have a substantial risk of transition to schizophrenia and should be a focus for assertive psychiatric intervention.