The SDIP patient is usually less ill than the schizophrenic one. Without first developing a substance dependency, the large majority of persons with a SDIP would likely never have developed any type of psychosis. Persons with a SDIP respond to antipsychotic medication very much the same as do schizophrenics. Like SDIP, schizophrenia is a functional psychosis. This means that problems of living and emotional traumas can act as precipitating factors for a psychosis.
Functional psychoses have genetic factors of various importance in their origin.
The functional element being involved in no way alters their status as true disease states. This means that in half of cases, only one twin will be schizophrenic. Functional psychoses are in contrast to organic psychoses- caused by temporary acute toxic states, permanent brain damage of various etiologies, and cerebral diseases such as Huntington s and Alzheimer s. Treatment of the dependency represents an opportunity for a specific type of therapy- that obviously isn't available for the true schizophrenic person. For the latter, essentially only the symptomatic, but still useful therapy of antipsychotic medication is available .