Patients with a certain genetic variant have been found to both be more pre-disposed to anxiety and depression and have lower susceptibility to the usual medication.

Although anxiety and depression can be developed due to distressing events or stressful periods in a person’s life, there is increasing evidence that some people are more predisposed to these disorders than others.

One pre-deposition factor is the serotonin transporter gene. Serotonin is an important neurotransmitter and has been shown to impact emotion, memory and learning. The serotonin transporter gene controls the uptake of serotonin and can therefore regulate its many effects.

Genetic variants in the serotonin transporter gene in humans have been associated with increased pre-disposition to anxiety and depression. In primate studies, those with the gene variant were more likely to judge a set stimulus as a higher threat that those without it. This effect is known as ‘Trait Anxiety,’ which is a strong risk factor for depression and anxiety in humans. However, a new study has indicated that as well as increasing the risk of getting anxiety or depression, having the genetic variant could mean that the normally prescribed anti-depressants are less effective.

Primates carrying the variant of the serotonin transporter gene, associated with higher anxiety, had a lower number of the type 2A serotonin receptors. As many medications for anxiety and depression target the 2A receptors, these results could explain why these drugs are not effective for approximately 1 in 3 people.

Patients that do not respond to the 2A targeting anti-depressants, known as SSRIs, may have more success with cognitive behavioural therapy. Testing patients for this variant could ensure that the right patients receive the medication, whilst those with the genetic variant are directed to alternative treatments.

1 in 4 people in the UK will experience a mental health issue every year. The NHS is therefore investing in more resources to help people manage these conditions. This study represents a major step forward in considering personalised medicine for mental illness and could improve management of mental health conditions in the future.  

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