Detecting psychotic spectrum dimension in unipolar "non psychotic" depression

Sub-clinical psychotic symptoms in the context of Major Depressive Disorder (MDD) may be detectable even before the full blown psychotic phenomenology Previous research has failed to systematically explore psychotic symptoms other than the presence/absence of delusions and hallucinations in MDD. In this study we assessed psychoticism dimension by means of the 6-items “psychotic features factor” of the MOODS-SR self-reported questionnaire (1) in a population of patients with non-psychotic MDD. Items content ranged from interpersonal sensitivity (“I felt very vulnerable”) to frank psychotic symptoms (“You heard voices”, “You felt surrounded by hostility as if everybody was against you” or “everybody was talking about you”). The Panic-Agoraphobic Spectrum (PAS-SR); the Social Anxiety Spectrum (SHY-SR), the Obsessive-Compulsive Spectrum (OBS-SR) and Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q) were also administered. Severity of depression was rated using Hamilton Rating Scale for Depression (HDRS-17) The study included 291 subjects diagnosed with non-psychotic MDD by means of the SCID-I, personality disorders were assessed using SCID-II interview. Chi-square test or T-test were used, as appropriate, to compare the two groups on clinical variables and ANCOVA, controlling for HDRS-17, was performed to compare the mean scores of the self-report spectrum instruments at two time points: baseline lifetime and beginning of the continuation phase Mean lifetime scores on psychotic features were 2.8±1.5. Using the cut-off score of 4, derived from ROC analysis, Low Psychoticism (LP) subjects were 182 (63,6%) and High Psychoticism (HP) were 104 (36.3%). HP subjects have an earlier onset of depressive illness and a lower quality of life. Age of onset was also significantly lower in HP patients with high mania/hypomania (measured using the cut-off of 22 of the MOODS-SR manic/hypomanic component) (22.2±9.9 vs 29.1±13.3, p<0.001). Depressive mood (p=0.045) and suicidality (p<0.001) factors mean scores of the MOODS-SR depressive component were significantly higher in HP subjects. HP patients had higher spirituality/mysticism (p=0.013) and mixed irritability (p=0.046) factors of the MOODS-SR manic/hypomanic component. All PAS-SR factors were significantly higher in HP patients with the exception of the medical reassurance, rescue object and loss sensitivity factors. Lifetime SHY-SR total score (p=0.038) was significantly higher in HP patients, but no differences were found in OBS-SR total score. Patients with higher lifetime psychoticism showed more residual symptoms in all spectrum instruments, regardless of severity of depression at the beginning of the continuation phase Paranoid and avoidant personality disorders were overrepresented in the HP group (10.9% vs 3.3% p=0.011; 28.7% vs 11.1%, p<0.001 respectively). Depressive patients with high psychoticism dimension represent a subgroup with earlier age of onset, lower quality of life, high manic/hypomanic features and more residual symptoms, possibly indicating a proximity to the bipolar spectrum. We suggest that clinicians should carefully consider subclinical lifetime psychotic experiences in the treatment of unipolar depression as expressions of proneness to psychosis.