Is Dopamine Behind Teenage ‘Rebelling’?

Adolescence: the memorable period where an individual transitions from puberty to adulthood. The vital biological changes that occur contribute to a teenager’s physical, psychological, and social development. As a result many experience characteristic behaviours, such as impulsive decision-making; quick loss of temper; experimentation with drugs and alcohol; and unprotected sex. Whilst these behaviours eventually allow transition into society, many mental illnesses, such as schizophrenia, can also emerge. Interestingly dopamine, a chemical that contributes to addiction; love; lust; and pleasure, has also been linked to these joys of adolescence.

Dopamine (Figure 1) modulates neural pathways that connect the frontal lobe with the striatum; thus motor, cognitive and behavioural functions of the brain. It does so via binding to excitatory (D1- like) and inhibitory (D2- like) receptors, influencing neurone activity. For instance D1 receptor stimulation stabilises active neuron states in the direct pathway (excitation of GABAergic neurons in the striatum), whereas D2 receptors inhibit these neurons in the indirect pathway. Studies have found that both receptor densities are amplified during adolescence, thus may excite the brain and lead to increased dopamine associated behaviours.

Figure 1: Dopamine Molecular Structure

 

Adult studies from the 1970’s found that administering dopamine increases “feel good” emotions, whilst agonists halt them. Using these findings, a hypothesized model of adolescent dopamine function depicts that increased signalling amplifies motivation via activating the direct, and inhibiting the indirect, pathway. Another mechanism behind teen behaviours is the significant changes the dopamine system undergoes, such as the increased plasticity of neurons.

Furthermore, abnormalities in signalling are implicated in the pathophysiology of mental disorders that often emerge in teenagers. This is supported by animal research, where adolescent rodents exhibited reinforcing effects to drugs, like amphetamines, that cause dopamine release. Teenagers also present reduced adverse responses to substances of abuse, such as milder withdrawal, and increased sensitivity to antagonists.

Nevertheless, despite an overall peak in signalling, many studies have also highlighted individual variability. This reminds us that genetic and environmental factors also come into play. Recent research now focuses on the effect of dopamine-related protein gene alleles. Read more below…

 

References:
Feature Photo from UK-Rehab

Dopamine Molecular Structure from Open Study

Padmanabhan, A., Luna, B. (2014) ‘Developmental imaging genetics: Linking dopamine function to adolescent behavior’ Brain and Cognition [online] 89, 27-38.

 

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Pritpal Kaur Klear

A enthusiastic Biological and Forensic Sciences graduate, with an interest in scientific writing.

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