Stressful events predict mood disorders

[David Baxter PhD]

Stressful events predict mood disorders in children of bipolar parents
Sept. 1, 2004
Psychiatry Matters

Stressful lifetime events appear to increase the risk of mood disorders developing in adolescents born to parents with bipolar disorder, suggest study findings that highlight the effect is independent of genetic vulnerability.

Manon Hillegers (Altrecht Institute for Mental Health Care, Utrecht, The Netherlands) and colleagues studied the effect of life events on the development of mood disorders in 140 Dutch adolescents who had parents with bipolar disorder.

In all, 38 (27%) of the children developed a mood disorder during follow-up, at a median age of 14 years.

The results, published in the British Journal of Psychiatry, showed that adolescents who developed mood disorders had experienced higher levels of stressful life events than those that did not develop such conditions.

Indeed, the life event load was significantly associated with approximately a 10% increase in the risk of mood disorder per unit life event load.

Moreover, although familial vulnerability was itself strongly associated with the development of mood disorders, adjustment for this variable had little effect on the relationship between stressful life events and mood disorder development.

"Both [factors] had independent effects on risk of mood disorders," the researchers write.

They also found that the impact of stressful life events principally accumulates, but at the same time gradually decays, as time goes by, at a rate of 25% per year.

"This suggests that the effects of stressful life events do not simply add up or rapidly extinguish but, in a gradually fading fashion carry over into the future risk of an episode of mood disorder," Hillegers and team comment.

"What drives the decay is not known, it might result from coping strategies or the effect of neutralizing life events."

Br J Psychiatry 2004; 185: 97-101

 

[Ash]

That is MOST interesting. Thank you, David!

Do you think that it's possible then to have family members who could have Bipolar and yet don't present symptoms?

 

[David Baxter PhD]

Do you think that it's possible then to have family members who could have Bipolar and yet don't present symptoms?

Yes, but I think it goes beyond that -- family members may never display symptoms...

What is inherited is a vulnerability or susceptibility which is probably a combination of biological (neurochemical-hormonal) factors and personality factors. Whether any of those genetic tendencies will be "expressed" (a geneticists' term) in the individual depends on life events, etc. -- the old "nature-nurture" interaction.

For example, individuals with a relative who suffers from schizophrenia may:
1. develop schizophrenia themselves
2. develop a mood disorder or anxiety disorder
3. develop a personality disorder
4. display some form of "neurotic" behavior (an archaic term)
5. not display any symptoms at all

For the case of schizophrenia, actually the most likely outcome is probably #2. However, it is still possible that this is the result of growing up with an unstable parent (nurture) rather than genetics (nature).

For bipolar disorder, the most likely outcome is probably #4 or #5.

I know of one family where the father is probably bipolar, a paternal uncle may be schizophrenic or suffer from recurrent depression, and 4 children are "normal" or asymptomatic, although one or two seem to have tendencies toward worrying or mild depression. Remember, that each of us gets our genetic makeup from two parents...

 

[Ash]

That is very, very interesting! I suppose I never really thought about it in those terms.

I've often wondered where I got the BP from! I wouldn't say any of my parents or grandparents are. Course, my mother is definitely what I would call "neurotic".

 

[David Baxter PhD]

It may have been developmental rather than "inherited" per se.

For example, there are some recent research findings that suggest there may be a link between the pregnant mom having 'flu and her child developing schizophrenia. Others very recently have suggested that there may be a link between early childhood diseases like rheumatic fever (I think that was one of them) and bipolar disorder.

We need to remember that even without a direct genetic "transmission" the developing human brain is quite fragile at a number of points -- fortunately, it is also highly resilient.

One suggestion as to why males are statistically more likely to exhibit symptoms of ADHD and other problems/disorders is that there are extra stages in fetal development for males compared to females, and therefore more opportunities for something to "go wrong".

All of this is still quite speculative but it does serve I think to remind us that there can be multiple causes of any of these disorders or disabilities.

 

[Ash]

All of this is still quite speculative but it does serve I think to remind us that there can be multiple causes of any of these disorders or disabilities.

True enough. That makes it all the more frustrating, though. <wink>