[Posted on 18 April, 2017 by Geir Øgrim]
A hairdresser served a large number of customers each day. He was asked; what is the reason for your success? He explained that all customers put their head into a machine that completes the hair cutting fast. But their heads are different sizes, how can they all be treated the same way? After the treatment, there are no differences, he answered.
Although medications are the most widely used treatments in psychiatry, they are (luckily) not as efficient as the hairdresser’s machine. Antidepressants, antipsychotics and psychostimulants are widely used. The clinical gains are continuously debated however. Within each diagnostic category, such as schizophrenia, depression, bipolar disorder, OCD, ADHD etc., there seem to be responders (REs) and non-responders (non-REs), patients suffering from side effects (SEs) and patients who do not (no SEs); probably because the diagnostic categories are heterogeneous. The neurobiological mechanisms behind observed behaviour may not be the same in all cases. My experience is first of all in ADHD, and I will limit my examples to this diagnosis.
Inattention is a core problem in ADHD, but a language disorder or a hearing problem may also result in similar symptoms, as will mental compulsions in OCD, and autistic preoccupations.
The brain areas involved are probably not the same in all these cases, and there is no reason to believe that a medication with a positive impact on inattention in one condition also will be the treatment of choice in another condition.
In my research I have worked with measures from quantitative EEG (QEEG), Event Related Potentials (ERPs) and a neuropsychological test (a cued visual go/no-go task) to find predictors of clinical gains and risk of side effects when ADHD is treated with psychostimulants. By combining variables that significantly discriminate between REs and non-REs, SEs and no SEs, we find that these indexes are powerful and clinically useful. The question of best options for non-REs remains unanswered so far.
There is a more general point in this: If the choice of psychotropic medication in the future is based more on brain related measures than on behaviourally defined categories, the number of cases helped by medication should increase. Based on test results, stimulants, SSRIs, antipsychotics etc., may also be used for untraditional indications.
We all prefer a personalised hairdresser, and not a one-size-fits-all machine, and similarly personalised medicine should be the future in (neuro)psychiatry.