Until now, no reliable biological markers of risk and relapse in substance-dependent patients have been identified. The yawn-inducing test with apomorphine has been proposed as a marker of the functional status of the dopaminergic system and therefore a predictor of suffering an addiction or predisposition to relapse.

Studying the safety and efficacy of apomorphine test as a predictor of relapse in intranasal cocaine dependent, diagnosed according to DSM-IV-TR.

We performed the test of apomorphine at the beginning (day 1) and end (day 11/12) of a detoxification program in 33 patients (29 men). The majority of patients relapsed after 22 weeks of follow up (87% relapse). The average yawns in the sample were 10.9 ± 9.3 in the initial test (Apo 1) and 10.2 ± 10.2 in the final test (Apo 2). The 42% of patients relapsed early (before 4 weeks) and 45% late (afther 4 weeks). 58% of the sample (N = 19), which did not fall belatedly filled an average of 8.0 yawns in Apo1 and 8.1 on Apo2 and 42% who did so early (N = 14), 14,8 in Apo1 and 14.6 in Apo2. Therefore there are an increased number of yawns in patients with early relapse. No important side effects were reported.

Patients with early relapse have a higher number of yawns that those falling late or abstainers The apomorphine test is a safe test and it is a readily applicable tool in clinical practice and may be a biological marker of risk.