From one-third to one-half of those seeking treatment for a substance-use disorder (SUD) can also have posttraumatic stress disorder (PTSD). The first multi-center study of PTSD among individuals seeking treatment for an SUD has found a greater prevalence of PTSD among those who were drug- rather than alcohol-dependent, and that having PTSD was associated with a more severe course and worse outcome for an SUD.
"We already knew that there is a quite relevant association between PTSD and SUDs," said Martin Driessen, professor of psychiatry at Ev. Hospital Bielefeld in Germany, and corresponding author for the study. "More specifically, PTSD is a risk factor for the development of an SUD, particularly a drug dependence. However, it was unclear whether this is true for both abusers and dependent subjects, or only one of these groups, which is why we studied clearly dependent subjects."
"Drug dependence has frequently been observed in war veterans who also suffer from PTSD," added Andreas Heinz, director and chair of the department of psychiatry at Charitι -- University Medical Center Berlin. "Both men and women often increase drug abuse and develop dependence following war and other trauma."
For this study, Driessen and his colleagues interviewed 459 subjects (274 males, 185 females) seeking help in 14 German addiction-treatment centers: 39.7 percent had alcohol dependence; 33.6 percent had drug dependence; and 26.8 percent had both. Interviewers used the International Diagnostic Checklists, Posttraumatic Diagnostic Scale, Addiction Severity Index, and Brief Psychiatric Rating Scale to assess all participants. Individual characteristics and treatment outcomes were later analyzed.
Results showed the prevalence of PTSD was greater among those with drug rather than alcohol dependence. "We found a prevalence of PTSD that was roughly double, around 30 percent, in drug-dependent subjects than that found in alcohol-dependent subjects, at about 15 percent," said Driessen. "Although we expected this, based on previous research, we were somewhat surprised to find such a high difference between drug and alcohol dependence."
Having a PTSD was also associated with worse outcomes for an SUD, Driessen said, such as more family problems, less employment, and more severe psychological symptoms.
"The subjects suffering from PTSD had higher hospitalization rates, shorter periods of abstinence, and higher drug craving," added Heinz. "However, the study did not show whether PTSD was a cause or consequence of drug dependence in individual subjects."
In addition, said Driessen, the associations between an SUD and PTSD were stronger when the PTSD diagnosis was definitive -- that is, based on the interview as well as the questionnaire -- compared to those patients with a probable or subsyndromal PTSD. A mere trauma exposure without PTSD was not associated with an SUD, he noted.
Both Driessen and Heinz recommended that clinicians examine patients with an SUD in order to determine if PTSD is an underlying factor, and that researchers continue investigating specific treatment options.
"Women in this study showed higher PTSD rates, which is in accordance with the literature," said Heinz. "Women also more often show clinical depression, which often precedes alcohol dependence, while in men, depression seems to follow alcohol dependence in most cases. Further research on psychotrauma and its sequelae such as PTSD, anxiety and depression may point to gender differences in the course and consequences of drug and alcohol addiction. In addition, neurobiological correlates such as monoamine and stress hormone dysfunction and alterations in central processing of affective and reward-indicating stimuli should be assessed. They may predict treatment response and indicate whether specific treatment options with psychotherapy or addictive pharmacological therapy are helpful."
Results are published in the March issue of Alcoholism: Clinical & Experimental Research.
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