That is, either the spectral sensitivity of the L cone shifts towards the M cone (blue shift), or that of the M cone shifts towards the L cone (red shift). These are then called anomalous cones and denoted by an asterisk (L* or M*). Since the mutated OPN1LW and OPN1MW genes are on the X chromosome, they are sex-linked, and therefore affected males and females disproportionately. Because the colorblind alleles are recessive, colorblindness follows X-linked recessive inheritance. Males have only one X chromosome (XY), and females have two (XX); Because the male only has one allele of each gene, if it is mutated, the male will be colorblind. Because a female has two alleles of each gene (one on each chromosome), if only one allele is mutated, the dominant normal alleles will "override" the mutated, recessive allele and the female will have normal color vision. However, if the female has two mutated alleles, she will still be colorblind. This is why there is a disproportionate prevalence of colorblindness, with ~8% of males exhibiting colorblindness and ~0.5% of females (0.08² = 0.0064 = 0.64%). The following table shows the possible allele/chromosome combinations and how their interactions will manifest in an individual. The exact phenotype of some of the combinations depend on whether the mutation yields an anomalous or non-functioning opsin. Blue cone monochromacy also follows these inheritance patterns, since it essentially a superposition of protanopia and deuteranopia. Y
male-only chromosome, no affect on colorblindness. X
X chromosome. M
(as subscript), normal M opsin. L
(as subscript), normal L opsin.
Research suggests that the prevalence of children with Major Depressive Disorder in Western cultures ranges from 1.9% to 3.4% among primary school children. Amongst teenagers, up to 9% meet criteria for depression in a given moment and approximately 20% experience depression sometime during adolescence. Studies have also found that among children diagnosed with a depressive episode, there is a 70% rate of recurrence within five years. Furthermore, 50% of children with depression will have a recurrence at least once during their adulthood. While there is no gender difference in depression rates up until age 15, after that age the rate among women doubles compared to men. However, in terms of recurrence rates and symptom severity there is no gender difference. In an attempt to explain these findings, one theory asserts that preadolescent women on average have more risk factors for depression when compared to men. These risk factors then combine with the typical stresses and challenges of adolescent development to trigger the onset of depression. Depression in youth and adolescence is associated with a wide array of outcomes that can come later in life for the affected individual. Some of these outcomes include poor physical and mental health, trouble functioning socially, and suicide. Suicidal intent
Like their adult counterparts, children and adolescent depression sufferers are at an increased risk of attempting or committing suicide. Suicide is the third leading cause of death among 15-to-19-year-olds. Adolescent males may be at an even higher risk of suicidal behavior when also presenting with a conduct disorder.