Testing a hypothesis arising from the epidemiology of schizophrenia in New Zealand

A selective literature review exploring the role of the nicotinic system in schizophrenia

Nicotine use is more prevalent in patients with psychiatric disorders, especially those diagnosed with psychotic illnesses. Previously, this higher prevalence has been partially attributed to the potential ameliorative effects of nicotine on symptom severity and cognitive impairment. Some healthcare professionals and patients perceive there is a beneficial effect of nicotine on mental health. Emerging data show that the harm associated with nicotine in the population of patients with mental health conditions outweighs any potential benefit. This paper will review the evidence surrounding the nicotinic system and schizophrenia, with a focus on any causality between nicotine and psychosis.

Mental health service users' progression from illicit drug use to schizophrenia in New Zealand

BACKGROUND

Recently, publications have hypothesised that the demonstrated increase in the incidence of schizophrenia in New Zealand is a side effect of the increased strength of available cannabis derivatives over the last 25+ years and the much more recent increase in the population's use of methamphetamine.

AIM

To compare the rates of later schizophrenia between age-matched mental health service users with initial diagnoses as alcohol abusers or illicit drug users.

METHOD

From the PRIMHD comprehensive national database, all users of the mental health services over a 5-year period who received an ICD-10 presenting diagnosis of alcohol or substance use/abuse were identified. For each person identified, the database was examined for the following 3 years to determine the numbers later diagnosed with schizophrenia.

RESULTS

For the initial alcohol problem people in their twenties, 1.7% were diagnosed as suffering from schizophrenia in the subsequent 3 years. For the initial drug problem people, the rate was 10.9%. Within that drug-using population, the indigenous Maori developed schizophrenia at a higher rate than did the remainder of the population.

CONCLUSION

These findings in New Zealand require further research into their generalisability, context and explanation.

A Comprehensive Review of Computational Methods for Automatic Prediction of Schizophrenia With Insight Into Indigenous Populations

Psychiatrists rely on language and speech behavior as one of the main clues in psychiatric diagnosis. Descriptive psychopathology and phenomenology form the basis of a common language used by psychiatrists to describe abnormal mental states. This conventional technique of clinical observation informed early studies on disturbances of thought form, speech, and language observed in psychosis and schizophrenia. These findings resulted in language models that were used as tools in psychosis research that concerned itself with the links between formal thought disorder and language disturbances observed in schizophrenia. The end result was the development of clinical rating scales measuring severity of disturbances in speech, language, and thought form. However, these linguistic measures do not fully capture the richness of human discourse and are time-consuming and subjective when measured against psychometric rating scales. These linguistic measures have not considered the influence of culture on psychopathology. With recent advances in computational sciences, we have seen a re-emergence of novel research using computing methods to analyze free speech for improving prediction and diagnosis of psychosis. Current studies on automated speech analysis examining for semantic incoherence are carried out based on natural language processing and acoustic analysis, which, in some studies, have been combined with machine learning approaches for classification and prediction purposes.