%dCDT Case Example
The patient is a 53 year old Caucasian male who was referred to the substance abuse clinic after he was sentenced by the court to drug and alcohol counseling for a driving while intoxicated (DWI) conviction. The patient reported that he considered himself an alcoholic “in recovery” but admitted that on the night of the arrest he had been drinking for the first time in three years. He estimated that he had about six drinks that night. He denied drinking since that episode, but did acknowledge a past history of heavy drinking (averaging 10 drinks a night for almost 3 years) that began in his forties after a divorce. At that time he began attending Alcoholics Anonymous (AA) and he was then abstinent for the three years prior to his reported “one-night relapse” that led to his DWI.
At the time of his current intake assessment in the substance abuse clinic, the patient did not want intensive alcoholism treatment since he was “not drinking” and was attending AA. He complained of worsening depressive symptoms and felt that his current dose of 40mg of fluoxetine (prescribed by his primary care provider) was not effectively treating these symptoms. A diagnosis of major depressive disorder (MDD), recurrent, was verified and it was recommended that he be followed on a regular basis in our dual diagnosis clinic for monitoring while we treated his depression. His fluoxetine was increased to 60mg and he agreed to laboratory testing. Liver transaminases (AST and ALT) and GGT were within normal limits, as was MCV. An initial %dCDT was 1.2%, corroborating the patient’s self-reports that he was not currently drinking.
At his next appointment he reported a substantial improvement in his depressive symptoms and endorsed continued abstinence from alcohol. Laboratory testing was repeated and while his GGT remained within normal limits his %dCDT increased to 1.6%. While this value was below the standard %dCDT cut-off of 1.7%, this result raised suspicion of heavy drinking since his value had increased by >30% since his last test (10). Two weeks later his GGT was still within normal limits and his %dCDT had increased to 2.0%. We discussed this with him at length and believed this value to be an indication of current heavy drinking.
He continued to deny alcohol use in spite of the fact that his %dCDT remained elevated at his next appointment (2.2%). He was asked to bring his significant other to an appointment later that week for corroborative information and while he agreed to this at first he eventually relented and admitted that he “had indeed been drinking regularly for the past 2 months”. Interestingly, as we were outlining a new and more intensive treatment plan, including outpatient detoxification, he added that he did not realize that lab tests for detecting alcohol use were so “accurate” since “my tests never showed that I was drinking before.” A review of this medical records indicated that his MCV, transaminases, and past GGT values from primary care had always been within normal limits, even during periods of heavy alcohol use.
The patient successfully completed our outpatient substance abuse program and has been abstinent from alcohol for several months. His depression continues to be in remission on fluoxetine therapy.
Jeffrey S. Cluver, MD
Director, Substance Abuse Treatment Clinic
Assistant Professor of Psychiatry
Associate Director of Residency Training
Medical University of South Carolina
Clinical Neurobiology Laboratory
67 President St. PH144
Charleston, SC 29425