So are mental illnesses a big benefit for capitalism as Mark Fisher said?
I would say no, and I think this misunderstands the nature of the claim.
The vested interests under capitalism benefit from exploitation, and because they benefit from exploitation they also benefit from the conditions that facilitate that exploitation.
The "social causation" model of mental illness, at the nexus with a critique of capitalism, suggests that it is either capitalist exploitation itself, or the conditions that are engineered to facilitate exploitation, that cause mental illness.
An example of this is the engineered "reserve army of labour" of unemployed that capitalist liberals always create when possible - either by artificially suppressing the economy at the margins until there is enough unemployment, or by flooding the market with surplus workers (often foreign labour). The purpose of this reserve army is to apply greater competitive pressure to workers, so as to force them to accept lower wages. Attacks on social security are also the norm for liberals.
In general, the poverty and insecurity that ensues from this model is prone to cause or exacerbate mental illness, which erodes the productivity of those workers who are victim to it, and reduces their effectiveness of reserve workers in applying competitive pressure.
Now, the mental illness itself is hardly beneficial to capitalist interests on any analysis. Rather, it is an undesirable byproduct of a strategy whose costs they weigh against its benefits.
It is true that certain vested interests - like big pharmaceuticals - may benefit from the treatment or management of mental illness so caused. But these interests are not necessarily synonymous with the interests of the whole system. This would be the "broken windows" fallacy.
And it is true that the capitalist system generally may benefit from the successful treatment or suppression of mental illness which arises as a byproduct of political policy, against the counterfactual where mental illness is caused but is left unmanaged. But it does not benefit against the counterfactual where mental illness simply does not exist. All other things being equal, the capitalists would prefer to intensify exploitation without inducing mental illness or having to deal with induced mental illness.
The real benefit of the "individual chemico-biological" view of mental illness, is not just because it maintains focus on managing the symptoms of political policy rather than altering it, but also because it provides an alternative explanation for mental illness under which the cause of mental illness is held to be something other than political policy.
If we accept that mental illness is caused by political policy, the issue is not just that it might generate impetus to change political policy, but that such impetus would encounter resistance from capitalist liberals who benefit from policies that facilitate exploitation, and such resistance would then make clear the existence of malicious forces in society that consider causing mental illness a reasonable price to pay for the profits they earn.
The recognition that such malicious governance exists and causes mental illness knowingly in the population in order to sweat the working class, would have a far more radicalising political effect than merely the acknowledgement that mental illness had social causes.
So in effect, there is a propaganda effect to consider, and the need to avoid people recognising that liberals already know the relationship between mental illness and political policy, but consider it an acceptable trade-off in a way that the masses would not (since the consequences for the masses, are both higher rates of capitalist exploitation and lower wages, and higher rates of mental illness).
I would also suggest that a lot of what is deemed "mental illness" is actually the early stages of a collective psychological re-adaptation to revolutionary action against oppressive political conditions.
@Obie2.0 has already mentioned the excellent example of "drapetomania", the characterisation of slaves running away from their masters in the American South as being mentally ill. The suggested medical remedy to this "illness" at the time, incidentally, was to "whip the devil out of them".
So-called counter-terrorism experts also increasingly wrestle with the problem that the distinction between mental illness and political radicalisation blurs, and that the more they are successful at disrupting organised plots which would create political change, the more it seems as though they are facing "self-radicalised" individuals and random attacks.
This is contrary to a theory in which terrorism primarily originates with a minority of ringleaders who spread an ideology like cancer. Instead it shows that organised plots form from individuals with a pre-existing propensity caused by their circumstances, who will coalesce and organise leadership if they can, but do not require coalescence and will act individually upon their circumstances if necessary.
And the more the politicians deploy resources to effectively manage such unorganised individuals at great expense - either treating them as criminals or as the mentally ill - the more they are undermining the profits that were to be made by the policies which are creating these by-product problems in the first place.
So in summary I would reiterate, capitalism does not benefit from mental illness. It benefits from political policies that create "mental illness" as a byproduct, and where there is also a long history of liberals casting even behaviour that is blatantly rational but politically undesirable to them - like slaves fleeing masters - as "mental illness".
