The association between antihypertensive medications and depression has been recognised for over 40 years. More recently, our understanding of the role of neurotransmitters in the aetiology of depression has helped us understand how antihypertensive drugs cause depression. Biogenic amine depletion is now believed to underlie the organic nature of depression, and many of the drugs used to treat hypertension interfere with this system.There is now compelling evidence that both reserpine and &agr;-methyldopa can induce or worsen depression through their actions on the central nervous system. &bgr;-Blockers have also been implicated, but the data supporting the link between these drugs and depression are not as certain. Guanethidine, clonidine, hydralazine, and prazosin appear to pose little risk in causing depression, although rare occurrences have been reported. Diuretics, calcium channel blockers, and angiotensin converting enzyme (ACE) inhibitors appear to have the lowest association with depression and are therefore the drugs of choice when depression is a risk.Physicians should know which drugs introduce the risk of causing or worsening depression. The wide array of medications now available to treat hypertension offers alternatives that pose low risk. All patients receiving medication to treat hypertension should be evaluated periodically for depression, and if depression occurs, medication should be suspected as playing a role in its aetiology.