[Clinical prognosis of schizophrenic patients with cannabis addiction. Between nihilism and hope]

Inhibition of return (IOR) in patients with schizophrenia and cannabis use

Research concerning the spatial orientation in patients with schizophrenia has demonstrated a state independent deficit in inhibition of return (IOR), which has been discussed as a vulnerability marker for schizophrenia. Other recent investigations on brain structure and cognitive processing have revealed less deficits in schizophrenia patients with comorbid cannabis use (SCH + CUD) compared to abstinent schizophrenia patients (SCH). It was hypothesized that these results may reflect a premorbid lower vulnerability in at least a subgroup of comorbid patients. The aim of the present study is to extend previous work by investigating IOR functioning in patients with schizophrenia and cannabis use. This in turn should supplement the existing studies on the vulnerability of this patient group. Therefore, we compared IOR functioning in four groups: 62 patients with schizophrenia and 46 healthy controls, both with and without cannabis use. Participants underwent a covert orienting of attention task (COVAT) with peripheral cues and three stimulus onset asynchronies (SOAs: 200 ms, 400 ms and 800 ms). Both schizophrenia groups displayed delayed IOR with a more pronounced IOR effect in SCH + CUD compared to SCH. In healthy controls, IOR did not seem to be significantly affected by cannabis use. Significant IOR-differences between groups were only seen between SCH patients without cannabis use and both healthy groups at SOA 400 ms. Patterns of cannabis use as well as clinical parameters of psychoses did not affect IOR. Our results may support the hypothesis of IOR as a vulnerability marker for schizophrenia and of a lower biological vulnerability in at least a subgroup of SCH + CUD.

Trans-Sector Integrated Treatment in Psychosis and Addiction

BACKGROUND

Patients with psychosis often develop comorbid addiction, with a lifetime prevalence of ca. 50%. Dual diagnoses are considered hard to treat. Long-term integrated treatment programs might improve such patients' outcomes, at least to a moderate extent, but they have not yet been adequately studied or implemented in Germany to date.

METHODS

100 dual diagnosis patients participated in a single-center, randomized, controlled trial under standard hospital treatment conditions. They were randomly allotted to two groups. Patients in the intervention group were admitted to a specialized open hospital ward, where they were given integrated treatment, including disorder-specific group therapy. Their treatment was continued with further disorder-specific group therapy in the outpatient setting. Patients in the control group were admitted to an open general psychiatric ward and received treatment as usual, but no disorder-specific treatment either during their hospitalization or in the subsequent outpatient phase. Follow-up examinations were performed three, six, and twelve months after inclusion. The primary outcome was defined as the changes in substance use and abstinence motivation. The secondary outcome consisted of the patients' satisfaction with treatment and with life in general, retention rate, psychopathology, rehospitalizations, and global level of functioning.

RESULTS

The patients in the intervention group developed higher abstinence motivation than those in the control group (p = 0.009) and transiently reduced their substance use to a greater extent (p = 0.039 at three months). They were also more satisfied with their treatment (group effect: p = 0.011). Their global level of functioning and their retention rate were also higher, but these differences did not reach statistical significance.

CONCLUSION

Low-threshold, motivational, integrated treatment programs with psycho-educative and behavioral therapeutic elements may be helpful in the treatment of dual diagnosis patients and should be more extensively implemented as part of standard hospital treatment. Larger-scale, methodologically more complex studies will be needed to identify subgroups of patients that respond to such treatments in different ways.