Changes in plasma noradrenaline and serotonin levels and craving during alcohol withdrawal

Despite substantial preclinical evidence that supports the involvement of noradrenergic (NA) and serotonergic (5-HT) mechanisms in alcohol withdrawal, human data remain inconsistent. We examined whether plasma levels of NA and 5-HT were altered during alcohol withdrawal and whether these measures were related to craving. We also explored whether alterations in NA and 5-HT activity differ between type I and type II alcohol-dependent patients during withdrawal.

Plasma measurements of NA and 5-HT and assessments of craving were performed longitudinally in 26 Caucasian alcohol-dependent men who were hospitalized for detoxification, at baseline (day 0), and on the 1st, 7th and 14th days of withdrawal. These measures were compared with NA and 5-HT levels obtained in 28 controls.

During withdrawal, NA levels declined significantly from day 1 through day 14, whereas 5-HT levels and craving declined significantly from day 0 through day 14. The NA levels on days 0 and 1 of withdrawal were significantly higher than those in controls; however, by day 7 the NA levels were similar to the control values. In contrast, the 5-HT levels on day 0 of withdrawal resembled control values; however, the 5-HT concentrations on days 1, 7 and 14 were significantly lower than those in controls. There were no significant correlations between NA and 5-HT levels or between craving and the biological measures during withdrawal. Type I and type II patients did not differ in NA or 5-HT levels during withdrawal.

These findings indicate that both plasma NA and 5-HT levels change during withdrawal; however, the pattern of change is different for the two measures. Also, while alterations in NA activity appear to normalize by late withdrawal, 5-HT changes seem to be more persistent. Neither craving nor subtypes of alcoholism seem to be related to alterations in NA or 5-HT during withdrawal.