Adolescent Cannabis Use Linked to Earlier Onset and More Hospitalizations in Schizophrenia

Among 160 patients with validated schizophrenia, the 32 with a cannabis history had earlier age at onset, higher number of hospital admissions, and higher total hospital days compared to the 128 without. There was no significant difference in type of onset or clinical symptom profiles between the groups.

Longitudinal follow-up of Swedish military conscripts with data on adolescent cannabis use and subsequent schizophrenia incidence. 160 patients with validated schizophrenia diagnoses assessed using the OPCRIT protocol. Compared disease characteristics between 32 with cannabis history and 128 without.

This study goes beyond asking whether cannabis causes psychosis to examine whether it makes the disease worse when it does occur. The finding that cannabis-associated schizophrenia involves more hospitalizations suggests a heavier disease burden with significant healthcare costs.

If adolescent cannabis use leads to not just higher risk of schizophrenia but also a more severe course, the public health implications extend beyond prevention of onset to the management and cost of treatment for those who develop the disorder.

Only 32 patients with cannabis history limits statistical power. Cannabis use measured at conscription may not capture full use history. Cannot separate the effects of pre-illness cannabis use from continued post-illness use. Male military conscripts may not represent the broader population.