Underestimation of substance abuse in psychiatric patients by conventional hospital screening

Psychiatric diagnosis mainly relies on behavioral signs and symptoms. Substance abuse can mimic the clinical presentation of primary psychiatric disorders and can also complicate the management of psychiatric patients. The reliability and accuracy of urine toxicology is a vital tool in the optimal treatment of these patients. Current demographics of substance abuse suggest that in addition to the most conventional drugs of abuse (e.g. cocaine, cannabis) that are of concern to treating physicians, prescription medications and new designer drugs also should be when evaluating patients who present with symptoms of psychosis/drug addiction or altered mental status.

Urine samples from 220 psychiatric inpatients admitted to either an acute drug and alcohol unit or acute psychiatric unit were analyzed for drugs by the standard hospital assay (KIMS) and by a more sensitive ELISA and GC-MS basic drug screening protocol.

The standard hospital toxicology (KIMS) was inferior to the ELISA and GC-MS methods in terms of both assay sensitivity and in detecting a broader number of drugs. The KIMS tests failed to identify opiates and amphetamine/methamphetamine in 50% of the patients. The KIMS screen did not identify zolpidem, buprenorphine and a number of synthetic drugs of abuse including cathinone and tryptamines.

In order to reliably identify substance abuse in patients with altered mental status in inpatient settings, analytical methodologies with adequate assay sensitivity and range to detect the vast majority of commonly abused illicit drugs and prescription medications are required for optimal clinical assessment and treatment.