MDD affects roughly 300 million people worldwide, which translates to approximately 4.5% of the global population.42 In 2010, it caused more DALY burden than diabetes.42 MDD diagnostic criteria include two or more weeks of decreased mood or markedly diminished interest or pleasure in most activities combined with one or more of the following criteria: severe change in appetite and sleeping habits, psychomotor agitation or retardation, excessive guilt, diminished concentration, or recurrent thoughts of death. First-line treatment currently includes selective serotonin reuptake inhibitors (SSRIs) and serotonin–norepinephrine reuptake inhibitors (SNRIs). Given the assumed mechanism of these medications, research has focused on finding genetic variants in the synthesis and signal conduction pathways of monoamines. Anxiety disorders follow closely behind MDD and affect about 4% of the global population.42 Anxiety disorders include panic, generalized anxiety, obsessive compulsive, posttraumatic stress and phobic disorders. They are all characterized by the presence of a persistent and severe anxiety, sense of dread or foreboding thoughts. First-line treatment includes a combination of psychotherapy with pharmacological agents, such as SSRIs.
