Mood and anxiety disorders are prevalent in all countries and cultures, which becomes obvious when standardized diagnostic and evaluation techniques are utilized. It is estimated that ~450 million people worldwide suffer from psychiatric illness. In the United States alone, epidemiologic research has identified that tens of millions of Americans suffer from major depressive disorder (MDD) annually, with many of them being in the prime of their adult lives. In addition to medical, personal, and social costs, depression is also believed to have a significant impact on work productivity. Further epidemiologic research indicates that nearly half of all individuals meeting lifetime criteria for MDD also have met criteria for a comorbid anxiety disorder. With an average age of 16 years for the onset of any lifetime anxiety disorder, anxiety disorders appear to predispose affected individuals to a substantial lifetime risk for MDD. In order to improve outcomes in depression and anxiety disorders, clinicians must enhance the entire process of recognition, diagnosis, and treatment.

Accurate comparisons of the prevalence of psychiatric disorders across Eastern and Western cultures are difficult and limited by methodological problems. Nevertheless, using standardized diagnostic and evaluation techniques, recent surveys have suggested that depression and anxiety disorders exist in all countries and cultures examined thus far, although variations in the prevalence rates and symptomatology may exist. This article discusses the influence and impact that culture can have on recognizing and treating mood and anxiety disorders, with a particular focus on Japan. Over the last 20 years, studies have consistently reported an increase in mental illness in Japan, especially symptoms of depression and anxiety. While such symptoms have had an adaptive cultural role in the past, current social and economic changes in Japan have turned any adaptive advantage into a potentially significant disadvantage, with a major impact on the capacity of individuals to function adequately. The situation is compounded by the fact that Japanese patients are reluctant to openly discuss disturbances of mood, since these are considered to be indicative of personal weakness rather than treatable medical conditions. Reluctance to discuss personal mental health hinders timely recognition and appropriate treatment.

Mood and anxiety disorders are among the most prevalent psychiatric illnesses and are associated with considerable morbidity and mortality. Selective serotonin reuptake inhibitors (SSRIs) are safe and effective treatments for major depression and anxiety disorders, and have become the most widely prescribed antidepressants worldwide. However, several issues limit SSRI treatment outcomes. Although SSRIs have a wider therapeutic margin and a milder side-effect profile compared to earlier antidepressants, even minor SSRI side effects can have a major impact on treatment outcomes by interfering with patient compliance. Nausea is one of the most common early SSRI side effects, and advances in SSRI delivery systems can diminish this. A controlled-release formulation of paroxetine targets the site of absorption for a more distal region of the small intestine, thereby avoiding the stimulation of upper gastrointestinal serotonin receptors that mediate nausea. The sustained-release characteristics also reduce the amplitude in blood level peaks and troughs, which may lead to diminished side effects and enhanced efficacy. Sexual side effects and weight gain are important sustained SSRI side effects, which affect compliance during continuation and maintenance phases of treatment. Several strategies address SSRI sexual side effects, including the use of adjunctive medication and/or manipulations in the scheduling of drug administration. Depression negatively impacts the management of many medical illnesses, including cardiovascular disease, cancer, and infectious diseases. The recognition and treatment of depression leads to improved outcomes in the management of breast cancer. Prophylactic SSRI treatment significantly reduces the incidence of interferon-associated depression and enhances completion rates in malignant melanoma.

Depression is a widespread and serious disorder that afflicts an estimated 13.1 to 14.2 million adults in the United States each year. Even more compellingly, the lifetime prevalence rate of depression in the US has recently been estimated to include 16.2% of adults (21% women, 13% men), or >32.6 million people. There are multiple putative “causes” of depression, with approximately one-third of an individual's propensity for unipolar depression due to genetic vulnerability, while the remaining two-thirds is due to environmental factors. Although the selective serotonin reuptake inhibitor (SSRI) antidepressants are believed to mainly act by selectively binding to the serotonin (5-HT) transporter to block reuptake of 5-HT from the synapse into the presynaptic nerve terminal, thereby increasing synaptic serotonin concentrations, some of the SSRIs also exhibit other neuropharmacologic effects. One such example is the high affinity for paroxetine in blocking norepinephrine reuptake. Another is the inhibition of dopamine reuptake by sertraline. In depression, hyperactivity of corticotropin-releasing factor (CRF)-producing neurons contribute to the well-characterized hypothalamic-pituitary-adrenal axis hyperactivity of depression. Increased activity of extrahypothalamic CRF circuits are believed to contribute to several depressive symptoms. Treatment and certain SSRIs have been shown to reduce the activity of CRF neurons and may contribute to their therapeutic action. Each SSRI apparently has its own unique pharmacologic properties that likely underlie their observed differences in clinical use.