Spectrums of health

Many conditions in psychiatry cannot be separated from normality/healthy states (e.g. depression) but even these broad diagnostic constructs may include syndromes like melancholia. There is still a debate as to whether psychotic-like experiences in the community are on a continuum with psychotic symptoms in those meeting diagnostic criteria for psychosis diagnostic constructs. Schizophrenia may exist on a continuum with related conditions (e.g. schizotypal personality disorder). There are differences between people meeting criteria for schizophrenia and healthy controls but none that can be used as a diagnostic test to separate the two, with the possible exception of anomalous self-experiences differentiating schizophrenia spectrum conditions from healthy controls and other diagnostic constructs. Several general medical conditions also exist on a continuum with health with no zones of rarity (e.g. hypertension and type 2 diabetes). Thresholds to meet criteria for these diagnostic constructs are chosen by expert committees often based on risk of developing complications (e.g. myocardial infarctions) and/or whether medical intervention may be beneficial. Even reasonably objective investigations can give abnormal results in healthy people. Concerns about whether thresholds are too low, leading to over-diagnosis, unnecessary treatment, and iatrogenic harm, also exist in general medicine. Other classifications in mental health will need to use thresholds in order to fulfil functions such as administration, research, or access to services. Dimensional classifications are good at representing the many spectrums of mental health.