Depression and anxiety are ubiquitous symptoms that are experienced by many patients in medical, surgical and primary care settings as well as in psychiatric practice. This chapter describes the range of options for drug and other physical treatments for depressive disorders, with an emphasis on unipolar depression. Monoamine oxidase inhibitors (MAOIs) were the first effective antidepressants and were discovered by accident when isoniazid used in the treatment of tuberculosis was shown to inhibit monoamine oxidase and was observed to elevate mood. The chapter discusses the drug treatments used in anxiety disorders. Selective serotonin reuptake inhibitors (SSRIs) are preferred to benzodiazepines as the first line of drug treatment for generalised anxiety disorder (GAD). A meta-analysis found that SSRIs and clomipramine was both superior to placebo in reducing the symptoms of obsessive-compulsive disorder (OCD) but found no evidence of greater efficacy of clomipramine over the SSRIs.