Substance-induced psychoses (SIP) are associated with greater conjugal ties, greater substance dependence, homelessness, parental substance abuse, poorer family support and visual hallucinations, while primary psychotic disorders (PP) have greater symptom severity.

To describe differential characteristics between PP and SIP in a dual diagnosis unit.

We collected sociodemographic, employment data, admission reasons, family substance abuse and main drug of abuse.

• • 23 patients were admitted with psychosis (87% males; mean age 35,6±10,1). Two groups were performed: PP (N=12) and SIP (N=11).

• • Mean length of admission was 17,78±13,17 days. Most prevalent co-occurrent diagnoses were psychotic disorders-cocaine use disorders (43,5%).

• • The only significant difference between PP and SIP was shorter length of admission in SIP (days: mean [s.d]) (26,6±14,9 vs. 13,8±7,5; p< 0.05). Other variables studied were: (1) main reasons for admission: hallucinations/delusions (33,3% vs. 90,9%), suicide ideation (33,3% vs. 0%); (2) main drug of abuse: cocaine (50% vs. 45,5%), alcohol (33,3% vs. 0%), psychoestimulants (0% vs. 27,3%), cannabis (8,3% vs. 18,2%); (3) marital status: married/cohabiting (25% vs. 36,4%), divorced (16,7% vs. 0%), single (58,3% vs. 63,6%); (4) employment: employed (33,3% vs. 50%) and unemployed (66,7% vs. 50%); (5) age, years: mean (s.d): 37,8 (10,6) vs 33,2 (9,5); (6) parental substance abuse (65,7% vs. 83,3%).

• • No significant differences were found between both groups (PP vs. SIP) except for shorter length of admission in SIP.

• • The most frequent co-ocurrent diagnosis was psychotic disorder+cocaine use disorder.