Background: Despite strong research interest in psychosis risk identification and the potential for early intervention, few papers have sought to document the implementation and evaluation of specialised psychosis related services. Assessment of Ultra High Risk (UHR) has been given priority, but it is equally as important to identify appropriate comparison groups and other baseline differences. This largely descriptive service evaluation paper focuses on the ‘baseline characteristics’ of referred clients (i.e., previously assessed characteristics or those identified within the first two months following service presentation). Methods: Data are reported from a 10-year layered service audit of all presentations to a ‘Psychological Assistance Service’ for young people (PAS, Newcastle, Australia). Baseline socio-demographic and clinical characteristics (N =1,997) are described (including clients’ psychosis and UHR status, previous service contacts, hospitalisation rates, and diagnostic and comorbidity profiles). Key groups are identified and comparisons made between clients who received ongoing treatment and those who were primarily assessed and referred elsewhere. Results: Clients averaged 19.2 (SD =4.5) years of age and 59% were male. One-tenth of clients (9.6%) were categorised as UHR, among whom there were relatively high rates of attenuated psychotic symptoms (69.1%), comorbid depression (62.3%), anxiety (42.9%), and attentional and related problems (67.5%). Overall, one-fifth (19.8%) experienced a recent psychotic episode, while a further 14.5% were categorised as having an existing psychosis (46.7% with a schizophrenia diagnosis), amongst whom there were relatively high rates of comorbid substance misuse (52.9%), psychosocial (70.2%) and physical health (37.7%) problems. The largest group presenting to PAS were those with non-psychotic disorders (43.7%), who provide a valuable comparison group against which to contrast the health trajectories of those with UHR and recent psychosis. Ongoing treatment by PAS was preferentially given to those experiencing or at risk for psychosis and those reporting greater current distress or dysfunction. Conclusions: Whether or not UHR clients transition to psychosis, they displayed high rates of comorbid depression and anxiety at service presentation, with half receiving ongoing treatment from PAS. Although international comparisons with similar services are difficult, the socio-demographic and comorbidity patterns observed here were viewed as largely consistent with those reported elsewhere.