There are higher rates of mental illness in groups with lower socioeconomic status (SES), but there is no clear consensus on the exact causative factors.
[2] The excess stress that people with low SES experience could be inadequate health care,[3] job insecurity,[4] and poverty,[5] which can bring about many other psycho-social and physical stressors like crowding, discrimination, crime, etc.
[further explanation needed] The Faris and Dunham (1939), Hollingshead and Redlich (1958), and Midtown Manhattan (1962) studies are three of the most influential[2] in the debate between social causation and downward drift.
Issues that are not experienced in high SES, such as lack of housing, hunger, unemployment, etc., contribute to the psychological stress levels that can lead to the onset of mental illness.
Additionally, while experiencing greater stress levels, there are fewer societal rewards and resources for those at the bottom of the socioeconomic ladder.
[2] The main focus of the research was to "uncover [the] unknown portion of mental illness which is submerged in the community and thus hidden from sociological and psychiatric investigators alike".
The Weich and Lewis study was conducted in the United Kingdom where researchers looked at 7,725 adults who had developed mental illnesses.
[12] In the Isohanni et al. longitudinal study in Finland, the researchers looked at patients treated in hospitals for mental disorders and who were aged between 16 and 29.
They found that individuals who were hospitalized at 22 years or younger (early onset) were more likely to only complete a basic level of education and remain stagnant.
[14] The researchers in the Wiersma, Giel, De Jong and Slooff study looked at both educational and occupational attainment of patients with psychosis compared to their fathers.
Although both models can be existing, they do not need to be mutually exclusive, researchers tend to agree that downward drift has more relevance to someone diagnosed with schizophrenia.
[18] Although social causation can explain some forms of mental illnesses, downward drift "has the greatest empirical support and is one of the cardinal features of schizophrenia".
Another reason why the downward drift theory is preferred is that, unlike other mental illnesses such as depression, once someone is diagnosed with schizophrenia they have the diagnosis for life.
Even with the help of antipsychotic medication and psycho-social support, most patients will still experience some symptoms[21] making moving up out of a lower SES nearly impossible.
As Livingston explains, "stigma can produce a negative spiraling effect on the life course of people with mental illnesses, which tends to create...a decline in social class".
While it can be hard to maintain status once the schizophrenia appears, some individuals are able to resist a downward drift, particularly if they start out at a higher SES.