Schizophrenia and Substance Abuse Co-Morbidity

Abstract

Objectives: To examine the evidence for a causal association between substance abuse and schizophrenia, and to discuss possible underlying mechanisms.

Methods: The search strategy included a keyword search using the following sources: Medline, Embase and Psychlit. Articles were selected on the basis of key words and hand search of the reference lists within these papers.

Results: There is an undeniable association between abuse of certain drugs and schizophrenia. More particularly, studies indicate that use of psychostimulants such as amphetamines and cocaine, as well as canna-bis, increase the likelihood of developing schizophrenia. Animal and human research indicates that repeated exposure to these drugs can lead to a sensitization of dopamine transmission similar to that observed in patients with schizophrenia.

Conclusion: The use of drugs which can cause dopamine sensitization appears to increase risk of schizophrenia, particularly in those with genetic or personality vulnerability.

Key Words:

• Schizophrenia
• psychosis
• addiction
• dual-diagnosis
• comorbidity
• BDNF
• psychostimulants
• cannabis
• sensitization
• vulnerability hypothesis