Heritability of psychiatric conditions – traditional versus current views
The traditional way of thinking about the heritability of psychiatric conditions is changing; no longer is it believed that the set of genes you were born with remain constant throughout life, as genes are constantly being changed and modified. The field of epigenetics studies the changes in an organism that occur by modification of gene expression, rather than the alteration of the genetic code itself. Epigenetic mechanisms are affected by in utero development, early childhood development, environmental chemicals, drugs and pharmaceuticals, ageing and diet.
Brain Derived Neurotrophic Factor – the importance of this gene, the meaning of low levels and subsequently, how to increase it.
As a person ages, their DNA naturally becomes more methylated, however, it has been found that there is accelerated epigenetic aging in patients with depression, which results in premature aging of anywhere between 1.5 and 5 years. The number of days spent depressed, or partially depressed, increases the methylation of DNA in the brain. Ongoing depression also causes decreased cell density of up to 48%, which results in impaired neural connectivity. This is important as it predicts disability. ‘You wouldn’t stop your heart medicine for fear of having small heart attacks and damaging the heart - don’t stop your medicine for depression either, as it can damage your brain!’ Epigenetic modulation of Brain Derived Neurotrophic Factor (BDNF) promoter gene results in lower levels of BDNF and a subsequent increase in depression and suicidality. Chronic stress also decreases BDNF and neural connectivity. Positive life events result in ‘small puffs of BDNF’, and when experienced on a regular basis, decreases the risk of depression. Positive life events are not necessarily limited to life-altering events, but can be small things that bring happiness, such as enjoying a great cup of coffee in the morning, laughing with colleagues or watching a sunset.
The importance of measurement based care was highlighted, and several tools which can be used in clinical practice were mentioned.
Prof Mattingly also emphasised the importance of measurement-based care, using rating scales that fulfilled three criteria – they must be free of charge, they should not be associated with a pharmaceutical company, and they should be easy for the patient to complete beforehand. He specifically cited the Patient Health Questionnaire (PHQ) – 9, as research has shown that ‘knowing the number’ is important to make appropriate adjustments to medication. Depressive symptoms should be measured before the patient sees a doctor – just as blood pressure (BP), cholesterol levels or glucose is monitored in patients with these conditions. Medication adjustments would not be made in patients whose BP had not been measured first and the same should apply to patients with depression.
Click here for part 2 of this report