Dimensions of positive symptoms in late versus early onset psychosis

Casenote studies have characterized late onset schizophrenia (LOS) and related psychoses as somewhat different symptomatically from patients with an early onset schizophrenia (EOS). This study examined a range of phenomenological aspects of delusions and hallucinations as well as traditional symptom measures in both groups.

34 LOS and 235 EOS completed the Positive and Negative Syndrome Scale, the Psychotic Symptom Rating Scales, and the Beck Depression and Anxiety inventories. Subgroups experiencing delusions were compared matching for chronological age and gender, and also when matched for chronicity and gender.

Delusions were very common at over 80% in both groups. LOS participants with delusions exhibited greater suspiciousness/paranoia, greater belief-conviction, and reduced insight when compared with the EOS group. These findings remained when matching for chronicity of illness, but disappeared when matching for chronological age. Hallucinations were surprisingly rarer in LOS (35%) than EOS (57%), with half the LOS group reporting whispers rather than clearly audible sounds. In general, anxiety, depression, and distress were as marked in LOS and EOS.

Similarities between EOS and LOS far outweighed the differences across a range of symptoms and measures. Greater delusional conviction, paranoia, and poorer insight in LOS were associated with the later age of onset rather than relating to chronicity of illness. As belief-conviction in LOS was not associated with increased grandiosity, disorientation, or unusualness of thought content, as it was in EOS, delusional conviction may be determined somewhat differently later in life.