What happens to someone missing teenage years of development? Hypothetically, let's say a person were to fall into a coma as an adolescent for several years, until they were a physical adult.

Would that person, assuming the brain was still fully functional upon awakening, still maintain the immaturity and impulsiveness of a teenager, and if so, could it be corrected by just trying to emulate adult life (effectively skipping teenage years of development), or are the experiences of a teenager still necessary to progress to an adult state of mind (aka, they would still need to have those experiences now in order to mature emotionally/mentally/etc.)?
Whilst typing this answer I upvoted this question as it points to very interesting theories of drive, motivation, and personal development.

Short Answer

If you take on board the theories surrounding life-span human development, there is an element of truth in your hypothesis.  Elements of immaturity and impulsiveness can still linger for various reasons and supposing there are no physical reasons for development delays, the reasons for the stagnation in cognitive development would need to be addressed through therapy in order for the person to be able to successfully move forward in life.

Long Answer

Although there is an element of opinion expressed in the underlying theories I am about to outline, the theories can easily be demonstrated in many different ways.

When looking at developmental issues, there are 5 spectrum models of development which theorists – and people in general – often disagree. (Miller, 2010; Sigelman &amp; Rider, 2012):


Goodness vs Badness of Human Nature
Humans are innately good, bad or neither
Nature vs Nurture
Genes, biology, and maturation vs experiences, learning and social influences
Activity vs Passivity
Humans shape their environments vs environmental forces shape humans
Continuity vs Discontinuity
Changes are gradual vs dramatically through life
Universality vs Context Specificity
Development is similar between people and cultures vs considerable differences between people and cultures


First of all we need to look at how the theory has been developed.

The prime theories of development which play a part in answering this question lay in Psychodynamic theories initially developed by Sigmund Freud and developed further with adjustments to his theories by Erik Erikson.

Sigmund Freud's Drive Theory and Stages of Development

Drive Theory

Sigmund Freud argued on the debate of Nature vs Nurture and Good vs Bad, especially when he wrote his 2 essays Thoughts for the Times on War and Death around 6 months after the outbreak of World War 1.  I am not sure where Freud stood on the other spectrums, although I would say that he stood on the universality side of Universality vs Context Specificity, as I believe he saw everyone had the same motivational drives and therefore everyone would react to situations in the same way.

With Sigmund Freud, lot of people get hung up on the sexual elements of his theories when really, Freud’s theories centres on his motivation and drive theory and they centre on all sorts of pleasure.  We are motivated towards whatever brings pleasure and are motivated away from pain, difficulty, destruction, confusion, etc.

With drive theory centring on Eros and Thanatos along with the elements of the self (id, ego and super-ego), he is explaining resistance and why people use avoidance tactics through ego-defence mechanisms such as repression, denial etc. The Freud Museum’s website explains this too, along with topics such as the Oedipus Complex (Freud Museum London, n.d.).

I have seen Freud’s drive theory in play in many different ways.  People who I have been supporting after being assaulted often display these characteristics.  Although not always, they will avoid at all costs, anything they feel will put them in the same situation again, even if that means sacrificing personal and social interactions.

Some will also seek other forms of pleasure, either just for the pleasure they gain from it, or for the purposes of blocking out bad feelings, memories and emotions they are suffering from due to the past experiences haunting them through flashbacks etc.

Even those who have not experienced assault display drive theory traits when you look at the effects of commercialism in society.  Everyone looks for the things that will give them pleasure, whether it is the latest mobile phone, laptop or computer; or if it is a future holiday or bigger home.  The increase in readily available loans such as payday loans also make things more accessible and those who find difficulty paying them back avoid looking at the letters of demand, burying their head in the sand in the hope that they can deal with it later or it will just go away.

Stages of Development

The stages of development are a central element of Freud's Drive Theory.  Each of the stages:


Oral (Birth - 1 year approx.)
Anal (1 – 3 years approx.)
Phallic (3 – 6 years approx.)
Latency (6 – puberty approx.)
Genital (Puberty–death approx.)


is associated with a particular conflict that must be resolved before the individual can successfully advance to the next stage.

Erikson’s Life Stages

Erik Erikson’s 8 life stages of man, originally put together in 1950 in his book Childhood and Society, reframes Freud’s life stages and expands them.  Each stage is a dilemma and the resolution of each dilemma results in either a positive or a negative outcome. (Roche, 2009)

In Erikson’s life stages, Freud’s oral stage is the stage of trust vs mistrust, the anal stage is autonomy vs shame and doubt, the phallic stage is initiative vs guilt, the latent period is industry vs inferiority and the genital stage is identity vs role confusion.

Later, Erikson split the genital stage and labelled the puberty period of genital stage as identity vs role confusion and the later part of genital stage is intimacy vs isolation (Erikson &amp; Erikson, 1998).

There were 2 other stages – Generativity vs Stagnation (or Fertility vs Sterility (Roche, 2009)) and Ego integrity vs despair – whilst a 9th stage was added in 1998 as the Eriksons came to believe that, “the role of old age needs to be reobserved, rethought” (Erikson &amp; Erikson, 1998: p. 62).

In the ninth stage (around the 80s/90s), all first eight stages go in reverse quotient order. For example, intimacy vs isolation becomes isolation vs intimacy – years of intimacy and love often give way to isolation and deprivation.  Relationships become “overshadowed by new incapacities and dependencies”.

Looking at how issues have affected people I have spoken to, the first 8 life stages are to me more like stages of assimilation of fact which can advance and recede at different times in life.  Different facts will be at different stages of assimilation.

Take for example identity vs role confusion.  You can feel very secure in your identity within society but then something can happen which can shake that sense of identity to the point where you start to question it again.  Using this “life-stage” as an example, if you speak to a man who has been raped, for many different reasons he may have questions surrounding his sexual identity which he didn’t have before.

He could then misinterpret the situations he was in and re-evaluate and re-introject his sexual identity in the wrong way, which when revisiting the past in therapy can then cause more pain and anguish having to yet again re-evaluate his sexual identity.

When looking at this theory in the context of life stages and not stages of assimilation, the Eriksons’ revisiting of the life stages in 1998 highlights how you also need to look at these stages in the context of time-frame in which it was written.  They were originally put together in the late 40s and put into a book in 1950.  Expectations of children and adults were different then and so the timeframes of each stage may need to be adjusted and re-evaluated, however the stages still hold as being valid.



References

Erikson, E. H. &amp; Erikson, J. M., 1998. The Life Cycle Completed. New York: W.W. Norton.

Miller, P. H., 2010. Theories of developmental psychology. New York: Worth.

Roche, D., 2009. Mapping the Human Phenome. [Online] 
Available at: http://thewayitis.info/thewayitis/inhumandev/epigenetics/mapphenome/p71.html
[Accessed 16 March 2017].

Sigelman, C. K. &amp; Rider, E. A., 2012. Life-Span Human Development. 7th ed. Belmont, CA: Wadsworth.

Freud Museum London, n.d. Are Freud's Theories All About Sex?. [Online] 
Available at: https://www.freud.org.uk/education/topic/10567/subtopic/10571/
[Accessed 16 March 2017]