Schizophrenia is associated with increased risk of subsequent substance abuse diagnosis: A nation-wide population-based register study

AIMS

We aimed to investigate whether or not a diagnosis of schizophrenia increases the risk of a substance abuse diagnosis.

DESIGN

Prospective cohort study using a longitudinal study design.

SETTING AND PARTICIPANTS

Individuals born in Denmark from 1955 to 1999 and registered in the Danish registers between 1 January 1968 and 1 July 2013.

MEASUREMENTS

We investigated the associations between schizophrenia and ICD diagnoses of substance abuse, both established through various Danish registers. The Cox regression model was used and adjusted for calendar year, gender, urbanicity, co-abuse, other psychiatric diagnoses, parents' substance abuse and psychiatric history, parents' immigration and parents' socio-economic position. Individuals diagnosed with substance abuse less than a year after diagnosis of schizophrenia were classified as not diagnosed with schizophrenia.

FINDINGS

The cohort consisted of 3 133 968 individuals. During follow-up (103 212 328 person-years at risk), a total of 14 007 individuals developed schizophrenia, with 2885 subsequently diagnosed with substance abuse. A diagnosis of schizophrenia was positively associated with the risk of developing substance abuse [hazard ratio (HR) = 3.69, 95% confidence interval (CI) = 3.56-3.83]. Additionally, adjusting for a co-abuse markedly affected the associations, making schizophrenia primarily associated with an increased risk of abuse of cannabis, alcohol, stimulants and other substances (adjusted HR = 2.48, 95% CI = 2.34-2.64 for cannabis; HR = 1.94, 95% CI = 1.87-2.02 for alcohol; HR = 1.77, 95% CI = 1.61-1.95 for stimulants; HR = 1.36, 95% CI = 1.20-1.54 for other substances). The association was still significant 10-15 years subsequent a diagnosis of schizophrenia (HR = 2.50, 95% CI = 2.26-2.76).

CONCLUSIONS

In Denmark a diagnosis of schizophrenia is significantly associated with increased risk of subsequent diagnosis of substance abuse.

Major clinical research advances in gynecologic cancer in 2018

Nineteen topics were selected as major clinical research advances in gynecologic oncology in 2018. For cervical cancer, the importance of human papillomavirus (HPV) testing alone as primary cervical cancer screening method and negative survival impact of minimally invasive surgery in early-stage cervical cancer were addressed. For ovarian cancer, cost-effectiveness of genetic testing to prevent cancer, use of analgesics and oral pill to reduce cancer risk, efficacy of secondary cytoreductive surgery and hyperthermic intraperitoneal chemotherapy, update in the use of poly (ADP-ribose) polymerase inhibitor, and efficacy of anti-angiogenic targeted treatments, including bevacizumab and tyrosine kinase inhibitors, were reviewed. For corpus cancer, sentinel lymph node mapping technique, adjuvant therapy in high-risk endometrial cancer (PORTEC-3), and targeted therapy in recurrent disease were covered. For the field of radiation oncology, survival outcomes of chemoradiation compared with chemotherapy alone in metastatic cervical cancer and new findings regarding the use of neoadjuvant chemotherapy in locally advanced cervical cancer were introduced. Lastly, for breast cancer, the use of talazoparib in patients with germline BRCA1/2 mutation, ovarian suppression for premenopausal patients, adjuvant chemotherapy guided by 21-gene assay, and combination therapy of atezolizumab and nab-paclitaxel for triple-negative cancer as well as promising overall survival results of palbociclib and fulvestrant in advanced breast cancer were briefly mentioned.

Association between alcohol, cannabis, and other illicit substance abuse and risk of developing schizophrenia: a nationwide population based register study

BACKGROUND

Several studies have examined whether use of substances can cause schizophrenia. However, due to methodological limitations in the existing literature (e.g. selection bias and lack of adjustment of co-abuse) uncertainties still remain. We aimed to investigate whether substance abuse increases the risk of developing schizophrenia, addressing some of these limitations.

METHOD

The longitudinal, nationwide Danish registers were linked to establish a cohort of 3 133 968 individuals (105 178 673 person-years at risk), identifying 204 505 individuals diagnosed with substance abuse and 21 305 diagnosed with schizophrenia. Information regarding substance abuse was extracted from several registers and did not include psychotic symptoms caused by substance abuse in the definition. This resulted in a large, generalizable sample of exposed individuals. The data was analysed using Cox regression analyses, and adjusted for calendar year, gender, urbanicity, co-abuse, other psychiatric diagnosis, parental substance abuse, psychiatric history, immigration and socioeconomic status.

RESULTS

A diagnosis of substance abuse increased the overall risk of developing schizophrenia [hazard ratio (HR) 6.04, 95% confidence interval (CI) 5.84-6.26]. Cannabis (HR 5.20, 95% CI 4.86-5.57) and alcohol (HR 3.38, 95% CI 3.24-3.53) presented the strongest associations. Abuse of hallucinogens (HR 1.86, 95% CI 1.43-2.41), sedatives (HR 1.68, 95% CI 1.49-1.90), and other substances (HR 2.85, 95% CI 2.58-3.15) also increased the risk significantly. The risk was found to be significant even 10-15 years subsequent to a diagnosis of substance abuse.

CONCLUSION

Our results illustrate robust associations between almost any type of substance abuse and an increased risk of developing schizophrenia later in life.

The Effect of Changes in Cannabis Exposure on Psychotic Symptoms in Patients With Comorbid Cannabis Use Disorder

OBJECTIVE

It remains unclear whether there is an association between severity of cannabis use and psychotic symptom severity over time. Shedding light on this under-researched matter could have clinical implications for this patient group.

METHODS

This was a secondary analysis of a randomized, parallel-group, superiority, assessor-blinded trial. We followed 60 patients with dually diagnosed psychosis and cannabis use disorders from the Danish CapOpus trial, which included assessments at baseline, post-treatment (6 months) and 10 months. Cannabis use was registered by self-report assisted by timeline follow-back. Psychotic symptoms were measured using the Positive and Negative Syndrome Scale (PANSS) positive, negative, and general symptoms scores. Analyses were adjusted for potential confounders.

RESULTS

Patients were classified into four categories: minor use (0-30 joints at baseline and 0-9 joints at follow-up; n = 19), moderate use (0-30 joints at baseline and 10-196 joints at follow-up; n = 11), high (reducing) use (31-240 joints at baseline and 0-9 joints at follow-up; n = 9), and severe use (31-240 joints at baseline and 10-196 joints at follow-up; n = 21). Those with severe and persistent cannabis use (severe use group) had significantly higher scores, as compared to those with minor use, on the positive symptom (17.0, 95% CI [4.7-19.2] vs. 12.7, 95% CI [10.4-15.0], respectively, adjusted p < .009) and general symptom (37.4, 95% CI [34.0-40.8] vs. 29.8, 95% CI [26.3-33.3], respectively, adjusted p < .003) scales at follow-up. The severe use group had significantly higher scores, as compared to the moderate use group, on the negative symptom scale at follow-up (17.4, 95% CI [15.1-19.7] vs. 12.5, 95% CI [9.3-15.6], respectively, adjusted p < .02). On the other hand, patients in the high (reducing) use group demonstrated the greatest improvement in psychotic symptoms on all three measures.

CONCLUSIONS

These findings are preliminary and more research must be done to elucidate the relationship between cannabis use and psychosis. Treatment of psychosis and comorbid cannabis use disorder could in the future incorporate treatment strategies emphasising encouragement to reduce cannabis use. CapOpus is registered at clinicaltrials.gov (NCT00484302).

The 4th Schizophrenia International Research Society Conference, 5-9 April 2014, Florence, Italy: a summary of topics and trends

The 4th Schizophrenia International Research Society Conference was held in Florence, Italy, April 5-9, 2014 and this year had as its emphasis, "Fostering Collaboration in Schizophrenia Research". Student travel awardees served as rapporteurs for each oral session, summarized the important contributions of each session and then each report was integrated into a final summary of data discussed at the entire conference by topic. It is hoped that by combining data from different presentations, patterns of interest will emerge and thus lead to new progress for the future. In addition, the following report provides an overview of the conference for those who were present, but could not participate in all sessions, and those who did not have the opportunity to attend, but who would be interested in an update on current investigations ongoing in the field of schizophrenia research.