New challenges for outpatient care: trends from twenty years of monitoring treatment demand in the city of Hamburg

Background: Since 1997, Hamburg, the second-largest city in Germany with a population of approximately 1.9 million, has been implementing a comprehensive monitoring system (BADO) to evaluate outpatient addiction treatment across all publicly funded facilities. This system plays a pivotal role in systematically tracking and analyzing service utilization, treatment processes, and patient outcomes.

Methods: The employed monitoring system, BADO, extends well beyond the parameters of Germany's core data set and the EMCDDA’s Treatment Demand Indicator (TDI). It encompasses additional domains such as biographical burdens, criminal prosecution, and the mental and physical dimensions of well-being. This comprehensive register has accumulated over 430 000 data sets from 1997 to 2023, corresponding to 320 000 treatment episodes across 180 000 distinct individuals.
In our analysis, we examined trends over the last 20 years, focusing on the main drug, sex, and age in relation to biographical burdens, criminal prosecution, and mental and physical well-being.

Results: We observe a notable decline in opioid users, approximately halving, alongside an increase in the age at both first and last treatment initiation. While the age of addiction onset shows a marginal increase, the sex distribution remains unchanged. 

In the case of alcohol-only users, there is a 25% decrease over the past 20 years. This group is characterized by an increasing average age and an upward trend in the age at both first and last treatment initiation. The proportion of female users in this category is rising.

Conversely, cannabis as the primary drug of use has seen a 60% increase in users, with a slight rise in the proportion of female users and the average age within this group. 

Regarding users with cocaine as their main drug, excluding those using opioids, there is a doubling in numbers. This group exhibits a slight increase in age at both first and last treatment initiation, with a stable gender distribution.

We also observe an increase in the use of amphetamines and MDMA during this period. However, there is no interpretable increase in the use of methamphetamine, cathinone, or new psychoactive substances over the last 20 years.

Conclusions: Over the past twenty years, BADO has documented a significant shift in the demographic and drug-use patterns among individuals seeking help, presenting new challenges to the outpatient addiction service system. Notably, there is a marked scarcity of evidence-based treatment options for users of cocaine and amphetamines.

Two decades ago, Hamburg's authorities prioritized early intervention strategies to target individuals at risk of developing substance use dependencies. However, our data suggests that these objectives have not been fully achieved. The anticipated outcomes, particularly in terms of reaching potential users at an earlier age, have not materialized, indicating a gap in effective early intervention measures.