Subclinical hallucinations in adolescent outpatients: an outcome study.

Objective: We assessed the continued prevalence at one year and association with clinical variables of subclinical hallucinations ascertained at baseline in a cohort of adolescent outpatients referred to a specialized early psychosis service. We further assessed the prevalence of psychiatric disorders in adolescents presenting subclinical hallucinations.

Method: 84 adolescent patients were sampled from a longitudinal, prospective study that assesses the course of clinical and neuropsychological measures in patients identified as at high clinical risk for psychosis. Subclinical hallucinations were measured using the Scale of Prodromal Symptoms (SOPS) with its companion interview manual (Structured Interview for Prodromal Symptoms, SIPS) [Miller, T.J., McGlashan, T.H., Woods, S.W., Stein, K., Driesen, N., Corcoran, C.M., Hoffman, R., Davidson, L., 1999. Symptom assessment in schizophrenic prodromal states. Psychiatr. Q. 70, 273-287; McGlashan, T.H., Miller, T.J., Woods, S.W., Rosen, J.L., Hoffman, R.E., Davidson, L., 2001. Structured Interview for Prodromal Syndromes (Version 3.0, unpublished manuscript). PRIME Research Clinic, Yale School of Medicine New Haven, Connecticut. ], and the Schizophrenia Proneness Instrument -Adult Version (SPI-A) [Schultze-Lutter, F., Addington, J., Ruhrmann, S., Klosterkötter, J., 2007. Schizophrenia Proneness Instrument (SPI-A). Giovanni Fioriti, Rome, Italy]. At one-year follow-up, only patients reporting subclinical hallucinations at initial assessment were studied.

Results: Full remission of subclinical hallucinations occurred in over half and at least partial remission in two thirds of these patients at one-year follow-up. Mood disorders were present in 62.5% of adolescents with subclinical hallucinations at initial assessment. SOPS measures for depression, deficient attention and for unusual/delusional thought were significantly associated with subclinical hallucinations at baseline. However, sustained experience of subclinical hallucinations at one-year follow-up was only predicted by the global level of functioning at baseline, while cannabis abuse, psychiatric and psychopharmacological treatment were not predictors.

Conclusions: Subclinical hallucinations occur across a wide range of mental states in adolescents and show high rates of remission. Our results warrant that the clinical meaning of such phenomena needs to be carefully weighed against the specific developmental phenomena in this particular age range.