Maternal behavior environmental factors

Figure 2 Anxiety pathways and their interactions. Two fundamentally different mechanisms involved in anxiety and anxiety-like behavior are proposed. The first mechanism is developmental, and its consequences are manifested later in life. Both genetic and environmental factors linked to anxiety can have a deveiopmental origin, as illustrated by the example of the s allele of the 5-HTT, the deficiency in the SHT receptor, and variability in maternal care. The second possible mechanism is not developmental but based on "acute" or current molecular abnormalities that result in anxiety or anxiety-like behavior. Examples include deficiencies in GABAergic neurotransmission and abnormalities in the central CRH system, which have the direct behavioral output of anxiety. It is also proposed that the developmental mechanisms lead to anxiety by converging on the "acute" mechanisms.

Beyond the genetic factors, the causes of ADHD are unknown and very few studies have examined the relationship between ADHD and exposures to environmental chemicals. It is known, however, that maternal prenatal exposures to lead, alcohol, tobacco smoke, and marijuana are known to result in the birth of children with high incidences of ADHDJ14-17 ft has also been established that exposure to excessive quantities of phenylalanine either prenatally in utero, as a result of the mother having phenylketonuria (PKU) and fetus not having PKU, or postnatally where the child has PKU, results in the development of ADHD hyperactive and behavioral... 

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