Depression and anxiety disorders are under-recognised in clinical practice. They are relatively common psychiatric disorders, affecting 2 to 5% of the population per year.Symptoms of depression and anxiety frequently co-exist in a given patient. Recent diagnostic criteria allow a differential diagnosis to be made based on the history of the symptomatology in the current psychiatric episode. The Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R), although not the only diagnostic scheme available, has become widely used, particularly for the diagnosis of anxiety states. Despite the relatively clear-cut diagnostic criteria of the DSM-III-R, the problem of comorbidity of diagnoses remains.Pragmatically, the differentiation of major depression and anxiety may not be very important, since pharmacological treatment of both disorders is heavily reliant on the use of antidepressant drugs.Tricyclic antidepressants, monoamine oxidase inhibitors (MAOIs) and selective serotonin (5-hydroxytryptamine, 5-HT) reuptake inhibitors (SSRIs) are all effective in the treatment of major depression and panic disorder. SSRIs and the tricyclic antidepressant clomipramine are effective in the treatment of obsessivecompulsive disorder, while MAOIs are effective in social phobia.Although their use has declined in recent years, due to concerns about tolerance and dependence, benzodiazepines have proven efficacy in the treatment of generalised anxiety disorder. At higher dosages, these agents are also effective in panic disorder.Some general guidelines on drug treatment for these disorders is presented.