Hi all
OPCRIT is a reliable diagnostic algorithm known to produce valid ICD-10 (and other) diagnoses of psychotic disorders, based on standardised case note review of 90 symptom items.
Using OPCRIT to produce ICD-10 diagnoses is useful for the major psychotic disorders including schizophrenia (F20), schizoaffective disorders (F25) and bipolar disorder (F30-31) and psychotic depression (F32-33). However, substance-induced psychotic disorders are not assigned their own category under the algorithm used to produce ICD-10 diagnoses, instead being lumped with other psychotic disorders, nos (i.e. F21-29 + F1X.5, excluding F25).
How would you go about teasing out people with a substance induced psychosis? Is this even possible? Various papers have noted this limitation, but I have not seen a workaround. Within the 90 OPCRIT items there is a section on lifetime dependence to alcohol, cannabis and other drugs (with or without affecting psychopathology), and I also have separate clinical ratings of ICD-10 diagnoses, so I could combine these with OPCRIT to code anyone who receives an OPCRIT non-affective diagnosis NOS AND a clinical diagnosis of F1X.5 to indicate a SIP. Would I be on safe ground here?
Thanks to the community,
James
Hello James,
First, let me apologize if I cover some basic ground that you are aware of. My understanding of a Substance-induced Psychotic Disorder is that is occurs primarily while the person is under the influence of the substance and may last at most a week after use. Based on this, I would have a drug test done to see if the person has substances in their system.
If the episode of psychosis had a quick onset and quick termination it might indicate a chemical cause.
Here is an old article on the subject. I hope it is helpful!
http://schizophreniabulletin.oxfordjournals.org/content/23/2/187.full.pdf+html
Hi James,
In my opinion it all depends if what you feed into OPCRIT are data for a single episode or lifetime. If there's a single episode (either the most recent or the most severe or, if you're working with FEP, the only one) I think what you suggest is the right solution (however be aware that in the ICD there's also affective psychoses substance induced - codes F1x.5; I don't know if for the OPCRIT they're there or in the Affective disorders NOS) Also you probably want to have some measure of the reliability of the clinical diagnoses before using them (e.g. how often they agree with the OPCRIT or, at least, as this is what you are looking for, are all clinical SIP diagnoses in the NOS category of the OPCRIT?) The duration of the episode is not a criterion on which I would base my ICD diagnosis (in the ICD text it is mentioned that SIP "usually remit in 6 months" ...)
If you're diagnosis is lifetime it's a tricky question. Mainly, I think, because the OPCRIT does this (i.e. lifetime diagnosis) but the ICD is essentially about episode diagnoses. So you could very well have [from the ICD point of view], for the same subject, an episode of SIP and several (non SI) affective episodes, some of them with psychotic symptoms For the same subject the OPCRIT will possibly end up with the "lump" of NOS psychoses.
Hope that helps!
Dear John and Andrei
Thank you both for your responses.
John, I agree that taking a more detail substance misuse battery, perhaps including a biological test, would be one way of getting at this problem. Unfortunately, I only have access to case notes and clinical diagnoses, and cannot return to the original participants (indeed, even if I could your idea would need to be administered prospectively).
Andrei - I'm thinking about FEP rather than lifetime, so that makes things a bit easier. Your point about checking the agreement between clinical and research based diagnoses is an important one in this regard.
Other views still welcomed
Thanks
James
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